If the current interglacial is going to naturally cause sea levels to rise 6.6 meters (21.6 feet) would you favor unnatural measures to stop it? Or would you prefer to lose south Florida as long as the cause isn't humans? In the last interglacial a lot more ice melted. At least that's the claim of a recent paper in Nature.
We find a 95% probability that global sea level peaked at least 6.6 m higher than today during the last interglacial; it is likely (67% probability) to have exceeded 8.0 m but is unlikely (33% probability) to have exceeded 9.4 m. When global sea level was close to its current level (≥-10 m), the millennial average rate of global sea level rise is very likely to have exceeded 5.6 m kyr-1 but is unlikely to have exceeded 9.2 m kyr-1.
A few readers might be trying to decide whether this latest paper supports whatever position they hold on catastrophic anthropogenic global warming (add the acronym CAGW to your memory banks if it is not already there) so they'll know whether to praise or scoff at this report. To those readers I say: give it a break.
So would you want to stop natural melting?
I'm curious to know whether interglacials ever reach a long stage where the ice melting and freezing balances for thousands of years? Or is it pretty much the case of net melting for thousands of years until net freezing begins? Anyone know?
Writing in Technology Review Duke University prof Franklin Hadley Cocks says even if a worst case scenario for global warming happens in a couple thousand years we'll be headed into the next Ice Age.
Even if the rate of growth could be moderated enough to stabilize levels at about 550 ppmv, average temperatures might well rise by about 5 oC--with devastating effects for us earthlings, such as rising sea levels and dramatic changes in weather patterns.
But even that warming will not stave off the eventual return of huge glaciers, because ice ages last for millennia and fossil fuels will not.In about 300 years, all available fossil fuels may well have been consumed.Over the following centuries, excess carbon dioxide will naturally dissolve into the oceans or get trapped by the formation of carbonate minerals. Such processes won't be offset by the industrial emissions we see today, and atmospheric carbon dioxide will slowly decline toward preindustrial levels. In about 2,000 years, when the types of planetary motions that can induce polar cooling start to coincide again, the current warming trend will be a distant memory.
For the last couple million years of the Quaternary Period You can see by looking at long term temperature graphs that the interglacial periods have been shorter than the glacial periods. Our civilization is very much a product of the current Holocene/Anthropocene interglacial period. We should try to make this period last.
I would prefer we didn't burn up all the limited supply of fossil fuels now so that we could burn them later when we really need to heat up the planet. But the average human discount rate precludes that sort of restraint and long term planning. We effectively can't even plan for 50 years from now. 2000 years is out of the question.
But I'm thinking 2000 years from now what we (those of us who live long enough to get full body rejuvenation and then avoid accidents and war) can find other ways to heat the planet. For example, we could use nuclear or solar energy to power synthesis of methane. Or we could synthesize and release the much more potent trifluoromethyl sulphur pentafluoride (SF5CF3). Or we could synthesize the most potent greenhouse gas nitrogen trifluoride, NF3. It is 17,000 times more potent than CO2. Surely in a couple thousand years we (or the artificial intelligences that take over the planet) will be able to find many ways to prevent the next ice age. So, absent an extinction event that wipes out intelligent life on the planet I do not expect the next ice age to happen on schedule.
The question of climate sensitivity to atmospheric carbon dioxide levels is unsettled. If we only knew the correct level of temperature sensitivity to CO2 concentration we would have a much more accurate view of what is in store for our climate future. But no. A new paper argues that the climate is far more sensitive to CO2 changes than previously thought.
The climate may be 30–50 percent more sensitive to atmospheric carbon dioxide in the long term than previously thought, according to a study published in Nature Geoscience yesterday.
Projections over the next hundreds of years of climate conditions, including global temperatures, may need to be adjusted to reflect this higher sensitivity.
Is this report correct? I think it illustrates how little we know about the potency of CO2 as a greenhouse warming gas. Here we are in 2009 and some researchers argue that the climate sensitivity to CO2 is much larger than previously thought. Will this turn out to be an underestimate or overestimate?
Sounds like a correlation study. Even assuming that it is possible to accurately measure temperatures millions of years ago the study doesn't prove the direction of causation.
A team of scientists, led by the University of Bristol and including the U.S. Geological Survey, studied global temperatures 3.3 to 3 million years ago, finding that the averages were significantly higher than expected from the atmospheric carbon dioxide levels at the time.
These underestimates occurred because the long-term sensitivity of the Earth system was not accurately taken into account. In these earlier periods, Earth had more time to adjust to some of the slower impacts of climate change. For example, as the climate warms and ice sheets melt, Earth will absorb more sunlight and continue to warm in the future since less ice is present to reflect the sun.
We could change the albedo (reflectivity) of the planet Earth by painting roofs white and cool the planet.
William Patterson of the University of Saskatchewan, says the Younger Dryas mini Ice Age came on in a matter of months.
JUST months - that's how long it took for Europe to be engulfed by an ice age. The scenario, which comes straight out of Hollywood blockbuster The Day After Tomorrow, was revealed by the most precise record of the climate from palaeohistory ever generated.
Around 12,800 years ago the northern hemisphere was hit by the Younger Dryas mini ice age, or "Big Freeze". It was triggered by the slowdown of the Gulf Stream, led to the decline of the Clovis culture in North America, and lasted around 1300 years.
Can our climate suddenly change drastically? Yes. We can't be assured of only slow gradual changes. Most of the time only slower changes happen. But rapid climate change is possible. For this reason I think we should develop the means to alter the climate on a global scale. We might some day need to reverse either a natural or human-made shift in climate.
Around 15,000 years ago, the Earth started warming abruptly after ~ 100,000 years of an "ice age"; this is known as a glacial termination. The large ice sheets, which covered significant parts of North America and Europe, began melting as a result. A climatic optimum known as the "Bölling-Allerød" was reached shortly thereafter, around 14,700 before present. However, starting at about 12,800 BP, the Earth returned very quickly into near glacial conditions (i.e. cold, dry and windy), and stayed there for about 1,200 years: this is known as the Younger Dryas (YD), since it is the most recent interval where a plant characteristic of cold climates, Dryas Octopetala, was found in Scandinavia.
The most spectacular aspect of the YD is that it ended extremely abruptly (around 11,600 years ago), and although the date cannot be known exactly, it is estimated from the annually-banded Greenland ice-core that the annual-mean temperature increased by as much as 10°C in 10 years.
That's an 18 F warming in ten years. Imagine your local climate changing that much that quickly.
Update: Some scientists think the Younger Dryas cooling was brought on by the bursting of the boundaries of a massive fresh water lake whose waters diluted the salt waters of the northern Atlantic Ocean and stopped the Gulf Stream. Therefore some argue we have no comparable plausible condition that can happen today to cause an equally sharp shift in climate. However, a massive upper atmosphere explosion of an asteroid is another possible explanation for the Younger Dryas. Such an asteroid collision with the Earth is certainly within the realm of the possible.
More generally, I think people have been lulled into complacency by a 20th century whose natural disasters were pretty mild. A century more like the 19th century is within the realm of the possible.
California experienced centuries-long droughts in the past 20,000 years that coincided with the thawing of ice caps in the Arctic, according to a new study by UC Davis doctoral student Jessica Oster and geology professor Isabel Montañez.
The finding, which comes from analyzing stalagmites from Moaning Cavern in the central Sierra Nevada, was published online Nov. 5 in the journal Earth and Planetary Science Letters.
Global warming gets a lot of attention due to the prospects of huge low lying areas getting submerged. But big changes in regional climate - whether human caused or not - seem much more interesting to me. Such changes could occur at any time.
Ratios of elements in stalagmites provide some indication of changing levels of precipitation.
The sometimes spectacular mineral formations in caves such as Moaning Cavern and Black Chasm build up over centuries as water drips from the cave roof. Those drops of water pick up trace chemicals in their path through air, soil and rocks, and deposit the chemicals in the stalagmite.
"They're like tree rings made out of rock," Montañez said. "These are the only climate records of this type for California for this period when past global warming was occurring."
Cooling periods make California wetter.
At the end of the last ice age about 15,000 years ago, climate records from Greenland show a warm period called the Bolling-Allerod period. Oster and Montanez's results show that at the same time, California became much drier. Episodes of relative cooling in the Arctic records, including the Younger Dryas period 13,000 years ago, were accompanied by wetter periods in California.
During the Medieval Warm Period what is now the western United States had an epic drought from 900 to 1300 AD. Imagine such a drought started in the 21st century. How to prevent large areas from becoming mostly uninhabitable due to lack of water? Could we build enough nuclear power plants near oceans to desalinate and pump water a thousand miles inland? What would be the cost?
Alternatively, could windmills in oceans upwind of continents be used to pump more moisture into the air before winds blow over continents? Picture a future where nanotechnology makes manufacturing cheap. This could become an affordable way to bring water inland.
OAK RIDGE, Tenn., Oct. 9, 2009 -- For the first time, climate scientists from across the country have successfully incorporated the nitrogen cycle into global simulations for climate change, questioning previous assumptions regarding carbon feedback and potentially helping to refine model forecasts about global warming.
My own reaction: amazement. We are in the year 2009 and only now the nitrogen cycle gets added to climate models? What other important factors are not yet in climate models? Does anyone know? I'm looking for a knowledgeable reply, not a rant. What is the state of climate models? What are the prospects for more accurate models 5, 10, 20 years from now?
These scientists expect more rapid climate change as a result of adding the nitrogen cycle.
The results of the experiment at the Department of Energy's Oak Ridge National Laboratory and at the National Center for Atmospheric Research are published in the current issue of Biogeosciences. They illustrate the complexity of climate modeling by demonstrating how natural processes still have a strong effect on the carbon cycle and climate simulations. In this case, scientists found that the rate of climate change over the next century could be higher than previously anticipated when the requirement of plant nutrients are included in the climate model.
ORNL's Peter Thornton, lead author of the paper, describes the inclusion of these processes as a necessary step to improve the accuracy of climate change assessments.
You might think climate models can be really accurate even without the nitrogen cycle. But recall a recent post I did about biofuels boosting nitrous oxide emissions and thereby causing big warming effects. Where the nitrogen goes and in what form is very important for the climate.
MBL, WOODS HOLE, MA—A report examining the impact of a global biofuels program on greenhouse gas emissions during the 21st century has found that carbon loss stemming from the displacement of food crops and pastures for biofuels crops may be twice as much as the CO2 emissions from land dedicated to biofuels production. The study, led by Marine Biological Laboratory (MBL) senior scientist Jerry Melillo, also predicts that increased fertilizer use for biofuels production will cause nitrous oxide emissions (N2O) to become more important than carbon losses, in terms of warming potential, by the end of the century.
Fertilizer usage is going to rise anyway due to increasing human population and industrialization. So how much will nitrous oxide emissions increase in the 21st century? Also, how much will fertilizer run-off and phytoplankton blooms increase? Will the Antarctic continent become livable as a result? Always look on the bright side of life.
You would have to go back at least 15 million years to find carbon dioxide levels on Earth as high as they are today, a UCLA scientist and colleagues report Oct. 8 in the online edition of the journal Science.
"The last time carbon dioxide levels were apparently as high as they are today — and were sustained at those levels — global temperatures were 5 to 10 degrees Fahrenheit higher than they are today, the sea level was approximately 75 to 120 feet higher than today, there was no permanent sea ice cap in the Arctic and very little ice on Antarctica and Greenland," said the paper's lead author, Aradhna Tripati, a UCLA assistant professor in the department of Earth and space sciences and the department of atmospheric and oceanic sciences.
Note that correlation does not prove causation in this case. The warming of the planet for other reasons would have freed up lots of CO2 from the ocean and permafrost. But it is quite possible a feedback loop drove the atmospheric CO2 up as more CO2 warmed up the planet releasing still more CO2 for still more warming.
I do not know whether the continuing increase in atmospheric CO2 concentrations will cause disastrous warming and shifts in precipitation patterns. But increasing the concentration of a warming gas in the atmosphere to a level last seen 15 million years ago is at very least a big gamble.
We ought to gradually shift away from fossil fuels usage. The key enabling technology for that shift is cheaper high energy density car batteries. In the United States 95% of transportation energy comes from oil. If we could power trains and cars with electricity that would reduce the economic disruption of the approaching post-Peak Oil period as well as reduce emissions of CO2 and more conventional pollutants.
Update:Since we can't be certain that we aren't setting ourselves up for a climate disaster by pushing up atmospheric CO2 to a level not seen in 15 million years you've got to ask yourself one question: Do I feel lucky?
Warming from greenhouse gases has trumped the Arctic's millennia-long natural cooling cycle, suggests new research. Although the Arctic has been receiving less energy from the summer sun for the past 8,000 years, Arctic summer temperatures began climbing in 1900 and accelerated after 1950.
The decade from 1999 to 2008 was the warmest in the Arctic in two millennia, scientists report in the journal Science. Arctic temperatures are now 2.2 F (1.2 C) warmer than in 1900.
To track Arctic temperatures 2,000 years into the past, the research team analyzed natural signals recorded in lake sediments, tree rings and ice cores. The natural archives are so detailed the team was able to reconstruct past Arctic temperatures decade by decade.
As part of a 21,000-year cycle, the Arctic has been getting progressively less summertime energy from the sun for the last 8,000 years. That decline won't reverse for another 4,000 years.
The new research shows the Arctic was cooling from A.D. 1 until 1900, as expected. However, the Arctic began warming around 1900, according to both the natural archives and the instrumental records.
What I want to know: If we wanted to select a temperature at which to stabilize the world's climate (since, after all, it naturally warms and cools) at what temperature would we need to stabilize it at to stop average global ice melting? My guess is that temperature is cooler than it is today. Is that temperature also cooler than it was in 1900?
If I understand this correctly the 1.2 C warming since 1900 reverses the last 6 thousand years of cooling (1.2 C divided by 0.2 C per thousand years).
The analysis shows that summer temperatures in the Arctic, in step with reduced energy from the sun, cooled at an average rate of about 0.36 F (0.2 C) per thousand years -- until the 20th century.
Naturally we should be cooling as we head back into the next ice age. But do you want the natural cycle to continue? Or do you want whatever climate we get as a side effect of continued industrialization? Or do you want to select a climate target and manipulate climate policy to achieve that target?
While satellites provide accurate and expansive coverage of ice in the Arctic Ocean, the records are relatively new. Satellites have only monitored sea ice extent since 1973. NASA's Ice, Cloud, and land Elevation Satellite (ICESat) has been on the task since 2003, allowing researchers to estimate ice thickness as well.
To extend the record, Kwok and Drew Rothrock of the University of Washington, Seattle, recently combined the high spatial coverage from satellites with a longer record from Cold War submarines to piece together a history of ice thickness that spans close to 50 years.
Analysis of the new record shows that since a peak in 1980, sea ice thickness has declined 53 percent. "It's an astonishing number," Kwok said. The study, published online August 6 in Geophysical Research Letters, shows that the current thinning of Arctic sea ice has actually been going on for quite some time.
Average sea ice thickness declined from 3.64 to 1.89 meters. But if 1980 was a peak then what was the ice like in the 1960s and 1970s? Anyone seen the paper?
During the Cold War, the submarines collected upward-looking sonar profiles, for navigation and defense, and converted the information into an estimate of ice thickness. Scientists also gathered profiles during a five-year collaboration between the Navy and academic researchers called the Scientific Ice Expeditions, or "SCICEX," of which Rothrock was a participant. In total, declassified submarine data span nearly five decades—from 1958 to 2000—and cover a study area of more than 1 million square miles, or close to 40 percent of the Arctic Ocean.
Kwok and Rothrock compared the submarine data with the newer ICESat data from the same study area and spanning 2003 to 2007. The combined record shows that ice thickness in winter of 1980 averaged 3.64 meters. By the end of 2007, the average was 1.89 meters.
How good is the instrumentation of the Earth's climate at this point? How many more sensors would be needed to measure heat flows accurately enough to adjust for major influences and create better future projections?
Changes in how large planets such as Jupiter and Saturn pull at the Earth's rotation cause the Earth to go into periodic cooling and warming periods.
CORVALLIS, Ore. – Researchers have largely put to rest a long debate on the underlying mechanism that has caused periodic ice ages on Earth for the past 2.5 million years – they are ultimately linked to slight shifts in solar radiation caused by predictable changes in Earth's rotation and axis.
In a publication to be released Friday in the journal Science, researchers from Oregon State University and other institutions conclude that the known wobbles in Earth's rotation caused global ice levels to reach their peak about 26,000 years ago, stabilize for 7,000 years and then begin melting 19,000 years ago, eventually bringing to an end the last ice age.
The melting was first caused by more solar radiation, not changes in carbon dioxide levels or ocean temperatures, as some scientists have suggested in recent years.
"Solar radiation was the trigger that started the ice melting, that's now pretty certain," said Peter Clark, a professor of geosciences at OSU. "There were also changes in atmospheric carbon dioxide levels and ocean circulation, but those happened later and amplified a process that had already begun."
Solar radiation changes rather than carbon dioxide (CO2) concentration changes initiated recent ice ages and warmings. So then is CO2 causing warming now?
A lot of people hope that carbon dioxide emissions do not cause global warming. I say they are making an error in how they look at the problem. Since changes in the Earth's orientation are driving us toward a cooling period all that coal and oil we burned might be all that is holding off another ice age. So I hope CO2 warms up the planet.
Sometime around now, scientists say, the Earth should be changing from a long interglacial period that has lasted the past 10,000 years and shifting back towards conditions that will ultimately lead to another ice age – unless some other forces stop or slow it. But these are processes that literally move with glacial slowness, and due to greenhouse gas emissions the Earth has already warmed as much in about the past 200 years as it ordinarily might in several thousand years, Clark said.
If CO2 is causing warming we probably ought to stop burning fossil fuels and instead reserve their burning for the future period when the solar radiation drops enough to cause an ice age.
CalTech profs are proposing that over the next couple of billion years as the Sun heats up and expands the life forms on Earth will gradually pull more nitrogen out of the atmosphere, lower atmospheric pressure, and allow more heat to escape, thereby delaying a big heating of the planet.
As the sun has matured over the past 4.5 billion years, it has become both brighter and hotter, increasing the amount of solar radiation received by Earth, along with surface temperatures. Earth has coped by reducing the amount of carbon dioxide in the atmosphere, thus reducing the warming effect. (Despite current concerns about rising carbon dioxide levels triggering detrimental climate change, the pressure of carbon dioxide in the atmosphere has dropped some 2,000-fold over the past 3.5 billion years; modern, man-made increases in atmospheric carbon dioxide offset a fraction of this overall decrease.)
The problem, says Joseph L. Kirschvink, the Nico and Marilyn Van Wingen Professor of Geobiology at Caltech and a coauthor of the PNAS paper, is that "we're nearing the point where there's not enough carbon dioxide left to regulate temperatures following the same procedures."
Kirschvink and his collaborators Yuk L. Yung, a Caltech professor of planetary science, and graduate students King-Fai Li and Kaveh Pahlevan, say that the solution is to reduce substantially the total pressure of the atmosphere itself, by removing massive amounts of molecular nitrogen, the largely nonreactive gas that makes up about 78 percent of the atmosphere. This would regulate the surface temperatures and allow carbon dioxide to remain in the atmosphere, to support life, and could tack an additional 1.3 billion years onto Earth's expected lifespan.
In the "blanket" analogy for greenhouse gases, carbon dioxide would be represented by the cotton fibers making up the blanket. "The cotton weave may have holes, which allow heat to leak out," explains Li, the lead author of the paper.
"The size of the holes is controlled by pressure," Yung says. "Squeeze the blanket," by increasing the atmospheric pressure, "and the holes become smaller, so less heat can escape. With less pressure, the holes become larger, and more heat can escape," he says, helping the planet to shed the extra heat generated by a more luminous sun.
Strikingly, no external influence would be necessary to take nitrogen out of the air, the scientists say. Instead, the biosphere itself would accomplish this, because nitrogen is incorporated into the cells of organisms as they grow, and is buried with them when they die.
In fact, "This reduction of nitrogen is something that may already be happening," says Pahlevan, and that has occurred over the course of Earth's history. This suggests that Earth's atmospheric pressure may be lower now than it was earlier in the planet's history.
Well, suppose the nitrogen doesn't naturally get removed from the atmosphere. Or suppose we (at least those of us who live long enough to get rejuvenated and live for extremely long periods of time) decide to prevent the atmospheric nitrogen depletion. What to do? The answer is obvious: increase the radius of Earth's orbit around the Sun. But how to do that? Any suggestions? It has to be done gravitationally I suspect. How to keep another body slightly tugging the Earth into a slowly increasing orbital radius?
Several of the rivers channeling less water serve large populations, including the Yellow River in northern China, the Ganges in India, the Niger in West Africa, and the Colorado in the southwestern United States. In contrast, the scientists reported greater stream flow over sparsely populated areas near the Arctic Ocean, where snow and ice are rapidly melting.
Dai and his co-authors analyzed the flows of 925 of the planet's largest rivers, combining actual measurements with computer-based stream flow models to fill in data gaps. The rivers in the study drain water from every major landmass except Antarctica and Greenland and account for 73 percent of the world's total stream flow.
Overall, the study found that, from 1948 to 2004, annual freshwater discharge into the Pacific Ocean fell by about 6 percent, or 526 cubic kilometers--approximately the same volume of water that flows out of the Mississippi River each year. The annual flow into the Indian Ocean dropped by about 3 percent, or 140 cubic kilometers. In contrast, annual river discharge into the Arctic Ocean rose about 10 percent, or 460 cubic kilometers.
In the United States, the Columbia River's flow declined by about 14 percent during the 1948-2004 study period, largely because of reduced precipitation and higher water usage in the West. The Mississippi River, however, has increased by 22 percent over the same period because of greater precipitation across the Midwest since 1948.
If the world heats up due to rising atmospheric carbon dioxide one of the most problematic effects will be shifts in precipitation patterns. The dry zones will likely expand. The American Southwest could be especially hard hit by drought. Note that very large scale droughts also occur naturally.
Here is the original paper (PDF).
Andrew Revkin of the New York Times reports on a recent study that found part of Africa went thru a drought that started in the 1400s and lasted over 3 centuries until 1750.
For at least 3,000 years, a drumbeat of potent droughts, far longer and more severe than any experienced recently, have seared a belt of sub-Saharan Africa that is now home to tens of millions of the world’s poorest people, climate researchers report in a new study.
The last really long drought in Africa occurred while Europe was going thru its Little Ice Age cold period.
The last such drought, persisting more than three centuries, ended around 1750, the research team writes in the April 17 issue of the journal Science.
Future big long-lasting droughts in Africa are inevitable (assuming no climate engineering). They are a natural occurrence. But human pollutants might make them occur more often and more severely.
Humans have inadvertently caused severe climate change in the past. The diseases brought from Europe to the Americas by Spanish and Portuguese explorers caused the collapse of the Aztec and Inca empires. The empire collapses caused abandoned farmland to revert to forests, sucking CO2 out of the atmosphere and probably helping to trigger the Little Ice Age. That cooling caused a big increase in food prices in Europe and lots of disease and starvation. Perhaps that cooling also caused (or at least contributed to) the multi-century dry spell in Africa.
The Western hemisphere is not immune from big climatic shifts. North America has also experienced century-long droughts over the last 7000 years.
Climate changes naturally. Climate is not naturally stable. Since humans harness a very substantial and increasing portion of all the world's biomass our margin for handling severe natural changes is shrinking by some measures. We would have a harder time tapping into a larger portion of the world's biomass if the total biomass shrunk for some (man-made or natural) reason. On the other hand, we do have more technology to use to buffer the effects of climate change on us - at least those of us who live in industrialized countries.
Some day when climate changes due to natural long term processes, human pollutants, volcanic eruptions, or a massive asteroid strike if you are still around don't be shocked. We've been living through a period of relatively less severe climate change. Unless we develop the ability and willingness to control long term climate trends this period of relative stability will end some day.
Update: An excellent February 2008 National Geographic article "Drying of the West" explores past, present, and future dry spells in the US West.
Stine found drowned stumps in many other places in the Sierra Nevada. They all fell into two distinct generations, corresponding to two distinct droughts. The first had begun sometime before 900 and lasted over two centuries. There followed several extremely wet decades, not unlike those of the early 20th century. Then the next epic drought kicked in for 150 years, ending around 1350. Stine estimates that the runoff into Sierran lakes during the droughts must have been less than 60 percent of the modern average, and it may have been as low as 25 percent, for decades at a time. "What we have come to consider normal is profoundly wet," Stine said. "We're kidding ourselves if we think that's going to continue, with or without global warming."
Human-caused sulfur aerosols cause cooling. Human-caused black carbon emissions absorb more sunlight and cause heating. Picture the carbon settling on ice and absorbing sunlight rather than letting the ice reflect sunlight back into space. Well, regulations in Western countries reduced sulfur aerosol emissions and therefore reduced the amount of human-caused cooling. Sulfur aerosols emissions and carbon particulate emissions play big roles in temperature changes. Global warming isn't just about carbon dioxide.
Though greenhouse gases are invariably at the center of discussions about global climate change, new NASA research suggests that much of the atmospheric warming observed in the Arctic since 1976 may be due to changes in tiny airborne particles called aerosols.
It matters where the pollution occurs since the particulates do not stay airborne for long.
Emitted by natural and human sources, aerosols can directly influence climate by reflecting or absorbing the sun's radiation. The small particles also affect climate indirectly by seeding clouds and changing cloud properties, such as reflectivity.
A new study, led by climate scientist Drew Shindell of the NASA Goddard Institute for Space Studies, New York, used a coupled ocean-atmosphere model to investigate how sensitive different regional climates are to changes in levels of carbon dioxide, ozone, and aerosols.
The researchers found that the mid and high latitudes are especially responsive to changes in the level of aerosols. Indeed, the model suggests aerosols likely account for 45 percent or more of the warming that has occurred in the Arctic during the last three decades. The results were published in the April issue of Nature Geoscience.
Carbon particulates cause cancer, respiratory disease, and heart disease. So efforts to cut carbon particulates pollution from coal electric plants, diesel engines, and other industrial activity would improve our health as well as keep more water bound up as ice.
Though there are several varieties of aerosols, previous research has shown that two types -- sulfates and black carbon -- play an especially critical role in regulating climate change. Both are products of human activity.
Sulfates, which come primarily from the burning of coal and oil, scatter incoming solar radiation and have a net cooling effect on climate. Over the past three decades, the United States and European countries have passed a series of laws that have reduced sulfate emissions by 50 percent. While improving air quality and aiding public health, the result has been less atmospheric cooling from sulfates.
One problem is that much of the carbon particulate pollution is coming from countries (most notably China) which place little importance on improving air quality. Parenthetically, Western countries have fed this process by exporting a lot of their manufacturing to a China that allows far more pollution from the same amount of manufacturing activity.
Increased black carbon particulate emissions from Asia have increased absorption of solar radiation while decreased sulfur aerosols from Western countries has cut the cooling effect of Western pollution.
At the same time, black carbon emissions have steadily risen, largely because of increasing emissions from Asia. Black carbon -- small, soot-like particles produced by industrial processes and the combustion of diesel and biofuels -- absorb incoming solar radiation and have a strong warming influence on the atmosphere.
The Northern Hemisphere has far more industrial activity. So the Arctic's temperature has risen more than the Antarctic's temperature.
The regions of Earth that showed the strongest responses to aerosols in the model are the same regions that have witnessed the greatest real-world temperature increases since 1976. The Arctic region has seen its surface air temperatures increase by 1.5 C (2.7 F) since the mid-1970s. In the Antarctic, where aerosols play less of a role, the surface air temperature has increased about 0.35 C (0.6 F).
China's pollution is on a massive scale. I see little chance we can convince the Chinese to cut their particulate pollution any time soon. But Western countries could at least cut their own particulate pollution and gain health advantages in the process.
Gregory Benford suggests we could cool the planet with silicon dioxide rather than sulfur as the cooling aerosol. Combine the silicon dioxide with a huge reduction in carbon particulates and we could stop the ice melt plus improve our health.
The Sun is at a 11 year low of a sunspot activity cycle. This cycle bottom is lower than typical for most of the last 100 years. Last time the Sun had fewer sunspots was 1913.
April 1, 2009: The sunspot cycle is behaving a little like the stock market. Just when you think it has hit bottom, it goes even lower.
2008 was a bear. There were no sunspots observed on 266 of the year's 366 days (73%). To find a year with more blank suns, you have to go all the way back to 1913, which had 311 spotless days: plot. Prompted by these numbers, some observers suggested that the solar cycle had hit bottom in 2008.
Maybe not. Sunspot counts for 2009 have dropped even lower. As of March 31st, there were no sunspots on 78 of the year's 90 days (87%).
It adds up to one inescapable conclusion: "We're experiencing a very deep solar minimum," says solar physicist Dean Pesnell of the Goddard Space Flight Center.
"This is the quietest sun we've seen in almost a century," agrees sunspot expert David Hathaway of the Marshall Space Flight Center.
Sometimes the Sun hits a minimum and stays there for an extended period of time. The Dalton Minimum from 1790 to 1830 and the Maunder Minimum from 1645 to 1715 each lasted for decades. The Maunder Minimum coincided with the coldest part of the Little Ice Age. Scientists have no way to predict when the Sun will go thru another extended period of low sun spots or whether we will suffer much colder weather as a consequence. So far we have no way to make accurate long term Sun weather forecasts.
COLLEGE PARK, Md -- A University of Maryland-led team has compiled the first decades-long database of aerosol measurements over land, making possible new research into how air pollution changes affect climate change.
Using this new database, the researchers show that clear sky visibility over land has decreased globally over the past 30 years, indicative of increases in aerosols, or airborne pollution. Their findings are published in the March 13 issue of Science.
"Creation of this database is a big step forward for researching long-term changes in air pollution and correlating these with climate change," said Kaicun Wang, assistant research scientist in the University of Maryland's department of geography and lead author of the paper. "And it is the first time we have gotten global long-term aerosol information over land to go with information already available on aerosol measurements over the world's oceans."
Different aerosols have different effects on temperatures. Black soot aerosols will absorb more sunlight and reduce the amount of light that reflects back into space. Therefore they should cause warming. Whereas sulfur aerosols will cause cooling. The effects of these aerosols are troubling because they have much shorter half-lives than CO2. Once Asian countries become advanced enough to want to clean up their air they'll cut back on aerosols emissions and very quickly the effect these aerosols have on climate will end. Maybe the aerosols are canceling out some of the effects of CO2. We'll find out eventually.
But the sun is shining brighter in Europe.
According to the authors, a preliminary analysis of the database measurements shows a steady increase in aerosols over the period from 1973 to 2007. Increased aerosols in the atmosphere block solar radiation from the earth's surface, and have thus caused a net "global dimming." The only region that does not show an increase in aerosols is Europe, which has actually experienced a "global brightening," the authors say.
The largest known source of increased aerosols is increased burning of fossil fuels. And a major product of fossil fuel combustion is sulfur dioxide. Thus, the team notes, that their finding of a steady increase in aerosols in recent decades, also suggests an increase in sulfate aerosols. This differs from studies recently cited by the Intergovernmental Panel Climate Change showing global emissions of sulfate aerosol decreased between 1980 and 2000.
I am surprised that in this database the US doesn't show a decline in aerosols given US emissions regulations. The shift toward use of Western US coal was driven in large part by emissions regulations to cut sulfur emissions. The Western coal is lower in sulfur than Eastern coal.
Recent data shows that waters have been rising by 3 millimetres a year since 1993.
Church says this is above any of the rates forecast by the IPCC models. By 2100, sea levels could be 1 metre or more above current levels, he says. And it looks increasingly unlikely that the rise will be much less than 50 centimetres.
Imagine the ocean about 3 feet higher. Got ocean-front property?
Professor Konrad Steffen from the University of Colorado, speaking at a press conference on Tuesday, highlighted new studies into ice loss in Greenland, showing it has accelerated over the last decade.
Professor Steffen, who has studied the Arctic ice for the past 35 years, told me: "I would predict sea level rise by 2100 in the order of one metre; it could be 1.2m or 0.9m.
Dr John Church of the Centre for Australian Weather and Climate Research, Hobart, Tasmania, Australia and the lead speaker in the sea level session, told the conference, "The most recent satellite and ground based observations show that sea-level rise is continuing to rise at 3 mm/yr or more since 1993, a rate well above the 20th century average. The oceans are continuing to warm and expand, the melting of mountain glacier has increased and the ice sheets of Greenland and Antarctica are also contributing to sea level rise."
New insights reported include the loss of ice from the Antarctic and Greenland Ice Sheets. "The ice loss in Greenland has accelerated over the last decade. The upper range of sea level rise by 2100 might be above 1m or more on a global average, with large regional differences depending where the source of ice loss occurs", says Konrad Steffen, Director of the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado, Boulder and co-chair of the congress session on sea level rise.
I expect oil burning to decline dramatically due to Peak Oil. But I'm less clear on the future of coal burning. Will it go up even faster in response to declining oil production? Or will it go down due to declining reserves of coal? The future CO2 levels depend on the size of economically extractable coal reserves.
A group of 3,146 earth scientists surveyed around the world overwhelmingly agree that in the past 200-plus years, mean global temperatures have been rising, and that human activity is a significant contributing factor in changing mean global temperatures.
Peter Doran, University of Illinois at Chicago associate professor of earth and environmental sciences, along with former graduate student Maggie Kendall Zimmerman, conducted the survey late last year.
The findings appear today in the publication Eos, Transactions, American Geophysical Union.
In trying to overcome criticism of earlier attempts to gauge the view of earth scientists on global warming and the human impact factor, Doran and Kendall Zimmerman sought the opinion of the most complete list of earth scientists they could find, contacting more than 10,200 experts around the world listed in the 2007 edition of the American Geological Institute's Directory of Geoscience Departments.
The climatologists are most certain that humans play a role in the planet's warming.
Two questions were key: have mean global temperatures risen compared to pre-1800s levels, and has human activity been a significant factor in changing mean global temperatures.
About 90 percent of the scientists agreed with the first question and 82 percent the second.
In analyzing responses by sub-groups, Doran found that climatologists who are active in research showed the strongest consensus on the causes of global warming, with 97 percent agreeing humans play a role. Petroleum geologists and meteorologists were among the biggest doubters, with only 47 and 64 percent respectively believing in human involvement. Doran compared their responses to a recent poll showing only 58 percent of the public thinks human activity contributes to global warming.
We are dumping a large amount of carbon dioxide into the atmosphere. It must be doing something. I do not think our ability to model climate is anywhere near good enough to predict how much the planet will heat up. Climate is an extremely complex system. We must make decisions about climate and CO2 emissions based on very partial information.
Our incomplete understanding of climate is not a rationale for does not mean
What I'd like to get out of the propagation of these beliefs: less conventional pollution from coal plants. Less particulates, less mercury, less oxides of sulfur. Use fear of global warming to overpower the coal and oil lobbies (nothing else has been strong enough to do this). If we have to cut back on coal to reduce CO2 emissions I'm happy since that'll cut back on pollutants that do more immediate harm. While we will pay a price for this I do not expect the price to be high. We can shift to nuclear for baseload electric power generation. Granted, there's a substantial lead time in making such a switch. But even with Obama in office a reduction in US coal usage doesn't look like a sure thing.
Despite a well-funded ad campaign by environmentalists attacking the industry, and a huge coal-ash spill in Tennessee that has led to calls for more regulation, the industry has received positive assurances this week from President-elect Barack Obama's nominees that the new administration is committed to keeping coal a big part of the nation's energy source.
Then there's China. Only a recession will slow China's coal consumption growth (and the Chinese coal electric plants are subject to far less environmental regulation). The US is going to drop far behind China in coal usage even without new political constraints on coal burning in the US. My guess is that the rate of growth of coal usage in the US will slow and perhaps stop as some industrial interests organize in favor of alternatives. GE can make money selling wind turbines and nuclear reactors.
The most detailed proposal yet by industry and environmentalists to reduce U.S. greenhouse-gas emissions will call for raising the costs of new coal plants and rewarding nations for protecting forests.
Rio Tinto Group, General Electric Co. and U.S. electricity producers will present the proposal tomorrow to a congressional committee and recommend “urgent” action, according to a copy of the report by the 32-member coalition obtained by Bloomberg News.
US coal mines can ramp up exports though.
NASA scientist James Hansen thinks quick action is needed to prevent eco-disaster. But we've got some things we can do if the climate warming becomes seriously bad. For example, we can paint roofs white, dump iron in the southern seas, or launch reflector satellites for $500 billion. But if you are looking for a frugal approach Gregory Benford proposes a way to cool the Earth for $100 million per year.
A big shift toward nukes, wind, geothermal, and solar power will cushion economies from the coming effects of declining oil production. It will also reduce conventional pollutants. It will probably end up helping reduce undesirable levels of global warming too.
MADISON — The decline of the Roman and Byzantine Empires in the Eastern Mediterranean more than 1,400 years ago may have been driven by unfavorable climate changes.
Based on chemical signatures in a piece of calcite from a cave near Jerusalem, a team of American and Israeli geologists pieced together a detailed record of the area's climate from roughly 200 B.C. to 1100 A.D. Their analysis, to be reported in an upcoming issue of the journal Quaternary Research, reveals increasingly dry weather from 100 A.D. to 700 A.D. that coincided with the fall of both Roman and Byzantine rule in the region.
The researchers, led by University of Wisconsin-Madison geology graduate student Ian Orland and professor John Valley, reconstructed the high-resolution climate record based on geochemical analysis of a stalagmite from Soreq Cave, located in the Stalactite Cave Nature Reserve near Jerusalem.
They didn't have diesel fuel to power irrigation pumps. They didn't have diesel bulldozers, trucks, steel, and concrete to construct massive water reservoirs and dams. They didn't have weather satellites or drought resistant crop strains. We have all those things and more. So we are more insulated (though not entirely so) from climate changes.
Regardless of whether humans are causing huge climate changes the climate will change. Look back over the last five hundred years and we see pretty big changes in climate. We will see more big changes. The Roman Empire and the Byzantine Empire went through big climate changes.
Their detailed climate record shows that the Eastern Mediterranean became drier between 100 A.D. and 700 A.D., a time when Roman and Byzantine power in the region waned, including steep drops in precipitation around 100 A.D. and 400 A.D. "Whether this is what weakened the Byzantines or not isn't known, but it is an interesting correlation," Valley says. "These things were certainly going on at the time that those historic changes occurred."
Today we are less dependent on the weather. Our biggest vulnerability is in energy supply. With enough energy we can desalinate and pump water long distances. If (or, rather, when) we develop the technologies needed to produce non-fossil fuels energy sources at low cost then I think we will be able to insulate ourselves (at least in most developed countries) from most climate changes.
Granted, a new ice age would require evacuation of some regions and countries. The melting of the polar ice caps would require other evacuations. But the richer we get the more easily we can adapt to climate changes. Given sufficient capital and energy we can handle anything short of a severe ice age and still maintain an industrial civilization.
Melting ice caps are avoidable with climate engineering. But food production could be maintained with sufficiently large amounts of cheap energy. We can desalinate water and pump it great distances. We can genetically engineer crops to handle different climates.
If we build enough nuclear reactors we can stop using coal for baseline electric power and also have plenty of energy to use to keep food production up in case of climate change. Also, if we go into a cooling period some day we could add coal electric to supplement the nuclear for heating and for crop production.
Andrew Revkin of the New York Times reports on a new paper that argues from a climate model that the Earth's climate will shift toward a colder world.
A new analysis of the dramatic cycles of ice ages and warm intervals over the past million years, published in Nature, concludes that the climatic swings are the gyrations of a system poised to settle into a quasi-permanent colder state — with expanded ice sheets at both poles.In essence, says one of the two authors, Thomas J. Crowley of the University of Edinburgh, the ice age cycles over the past million years are a super-slow-motion variant of the dramatic jostlings recorded by a seismograph in an earthquake before the ground settles into a new quiet state. He and William T. Hyde of the University of Toronto used climate models and other techniques to assess the chances that the world is witnessing the final stages of a 50-million-year transition from a planet with a persistent warm climate and scant polar ice to one with greatly expanded ice sheets at both poles.
This isn't expected to happen in the next 100 years. At this point the result probably doesn't have any policy implications. But for those of us who live long enough to receive rejuvenation therapies if the robots or nanobots do not wipe us out at some point we'll need to argue about whether to engineer the climate to prevent another ice age.
Revkin posted a series of responses to this paper. Here's part of a response from NASA climate scientist James Hansen arguing that humans could easily prevent a deeper freezing by producing chloro flouro carbons. I agree. But CFCs are a bad choice due to their effects on the ozone hole.
Another ice age cannot occur unless humans go extinct. It would take only one CFC factory to avert any natural cooling tendency. Our problem is the opposite: we cannot seem to find a way to keep our GHG forcing at a level that assures a climate resembling that of the past 10,000 years.
Introduction of greenhouse gases isn't the only way to prevent a new ice age. We also could make all our buildings black on the outside and our roads too. That'd make the planet absorb more light.
This model does not prove the future. Carl Wunsch of MIT complains this model isn't science because the model is too simple and unproven.
Surely this isn’t science in any conventional sense. Taking a toy model and using it to make a “prediction” about something nearly a million years in the future, is a form of science fiction—maybe interesting in the same way a novel is, but it isn’t science. The prediction itself is untestable—except a million years from now, and the model “tests” that quoted are carefully chosen to be those things that the model has been tuned to get “right,” with no mention of the huge number of things it gets wrong. How many times do “if”, and “may” get used in the paper?
While this is simpler than the average climate model all climate models are simple (at least compared to the system they attempt to model) and unproven. A planetary scientist of my acquaintance tells me that all climate models have large errors in them and aren't really science because they can't predict. But they are the best available and we need to make decisions based on incomplete understanding.
Update: Lest anyone miss the point: The reason this model has no present day policy implications is that the time line for this projected cooling is not in this century. Whereas models that project global warming due to carbon dioxide emissions do project warming in this century. I do not know whether the latter models are correct. I'm told they have large sources of error in them. But they might be correct. We deal with large uncertainties with regard climate. We need to make decisions based on incomplete and partially erroneous information.
Once we have rejuvenation therapies some of us might some day need to consider policy changes in response to some future more refined model that will project cooling changes at some point some of us might just live to see.
ATHENS, Ohio (Aug. 19, 2008) – A stalagmite in a West Virginia cave has yielded the most detailed geological record to date on climate cycles in eastern North America over the past 7,000 years. The new study confirms that during periods when Earth received less solar radiation, the Atlantic Ocean cooled, icebergs increased and precipitation fell, creating a series of century-long droughts.
A research team led by Ohio University geologist Gregory Springer examined the trace metal strontium and carbon and oxygen isotopes in the stalagmite, which preserved climate conditions averaged over periods as brief as a few years. The scientists found evidence of at least seven major drought periods during the Holocene era, according to an article published online in the journal Geophysical Research Letters.
“This really nails down the idea of solar influence on continental drought,” said Springer, an assistant professor of geological sciences.
The sun is not a reliable supplier of light radiation. You can't trust the sun. It gets all bent out of shape by magnetic field fluctuations.
Geologist Gerald Bond suggested that every 1,500 years, weak solar activity caused by fluctuations in the sun’s magnetic fields cools the North Atlantic Ocean and creates more icebergs and ice rafting, or the movement of sediment to ocean floors. Other scientists have sought more evidence of these so-called “Bond events” and have studied their possible impact on droughts and precipitation. But studies to date have been hampered by incomplete, less detailed records, Springer said.
But we hopefully have hundreds of years to prepare for the next megadrought.
The climate record suggests that North America could face a major drought event again in 500 to 1,000 years, though Springer said that manmade global warming could offset the cycle.
If humans survive for the next 500 years and I'm still alive in a rejuvenated body I'm looking forward to the opportunity to do climate engineering to prevent a massive drought.
BOZEMAN -- The sun has been laying low for the past couple of years, producing no sunspots and giving a break to satellites.
That's good news for people who scramble when space weather interferes with their technology, but it became a point of discussion for the scientists who attended an international solar conference at Montana State University. Approximately 100 scientists from Europe, Asia, Latin America, Africa and North America gathered June 1-6 to talk about "Solar Variability, Earth's Climate and the Space Environment."
The scientists said periods of inactivity are normal for the sun, but this period has gone on longer than usual.
The climate always changes. Natural forces will cause big climate changes even if humans do not interfere.
The 11 year sun spot cycle reminds me of women who fear pregnancy and wait for their late menstrual cycle. We are late on the warming part of the solar cycle. Have you started to worry yet?
The last cycle reached its peak in 2001 and is believed to be just ending now, Longcope said. The next cycle is just beginning and is expected to reach its peak sometime around 2012. Today's sun, however, is as inactive as it was two years ago, and scientists aren't sure why.
"It's a dead face," Tsuneta said of the sun's appearance.
Tsuneta said solar physicists aren't like weather forecasters; They can't predict the future. They do have the ability to observe, however, and they have observed a longer-than-normal period of solar inactivity. In the past, they observed that the sun once went 50 years without producing sunspots. That period coincided with a little ice age on Earth that lasted from 1650 to 1700.
Cold weather would shorten growing seasons and therefore reduce crop yields. Cold weather would also raise heating costs and other costs associated with winter such as plowing. All this would happen while the world oil production declines.
But I'm not talking about the late start of the next sun cycle to alarm you. Oh no. Why get alarmed about something that would make for an exciting science fiction adventure movie?
The bleak truth is that, under normal conditions, most of North America and Europe are buried under about 1.5km of ice. This bitterly frigid climate is interrupted occasionally by brief warm interglacials, typically lasting less than 10,000 years.
The interglacial we have enjoyed throughout recorded human history, called the Holocene, began 11,000 years ago, so the ice is overdue. We also know that glaciation can occur quickly: the required decline in global temperature is about 12C and it can happen in 20 years.
The next descent into an ice age is inevitable but may not happen for another 1,000 years. On the other hand, it must be noted that the cooling in 2007 was even faster than in typical glacial transitions. If it continued for 20 years, the temperature would be 14C cooler in 2027.
By then, most of the advanced nations would have ceased to exist, vanishing under the ice, and the rest of the world would be faced with a catastrophe beyond imagining.
Suppose another ice age started. Think about all the massive desperate large scale engineering efforts that would be undertaken in order to prevent the enormous disaster that would befall us.
But how to heat the planet? Cooling it is a lot easier. How to prevent a new ice age? Anyone come across some good proposals on this? A massive release of methane into the atmosphere perhaps?
What, me worry? Anthony Watts summarizes the latest data on planetary cooling.
Confirming what many of us have already noted from the anecdotal evidence coming in of a much cooler than normal May, such as late spring snows as far south as Arizona, extended skiing in Colorado, and delays in snow cover melting, (here and here), the University of Alabama, Huntsville (UAH) published their satellite derived Advanced Microwave Sounder Unit data set of the Lower Troposphere for May 2008.
It is significantly colder globally, colder even than the significant drop to -0.046°C seen in January 2008.
The global ∆T from April to May 2008 was -.195°C
2008 1 -0.046
2008 2 0.020
2008 3 0.094
2008 4 0.015
2008 5 -0.180
Compared to the May 2007 value of 0.199°C we find a 12 month ∆T is -.379°C.
I like being able to walk to work in June without working up a major sweat. So far it doesn't seem like a problem to me.
Many climate models show a steadily hotter century because of atmospheric carbon dioxide build-up. But Dr. Noel S. Keenlyside and colleagues at the Leibniz Institute of Marine Sciences in Kiel, Germany and at the Max Planck Institute for Meteorology in Hamburg predict in a paper in Nature that global temperatures might stay flat or decline in the next decade.
One of the first attempts to look ahead a decade, using computer simulations and measurements of ocean temperatures, predicts a slight cooling of Europe and North America, probably related to shifting currents and patterns in the oceans.
The team that generated the forecast, whose members come from two German ocean and climate research centers, acknowledged that it was a preliminary effort. But in a short paper published in the May 1 issue of the journal Nature, they said their modeling method was able to reasonably replicate climate patterns in those regions in recent decades, providing some confidence in their prediction for the next one.
This model might not be correct. But suppose this model is correct. Then the climate models which predict warming due to CO2 emissions are inaccurate at least for the next decade. These models might be accurate in their longer term predictions. But we might not know that based on what happens in the next decade.
It may partly explain why temperatures rose in the early years of the last century before beginning to cool in the 1940s.
"One message from our study is that in the short term, you can see changes in the global mean temperature that you might not expect given the reports of the Intergovernmental Panel on Climate Change (IPCC)," said Noel Keenlyside from the Leibniz Institute of Marine Sciences at Kiel University.
His group's projection diverges from other computer models only for about 15-20 years; after that, the curves come back together and temperatures rise.
On the bright side, in 15 to 20 years we'll have much better climate models and also better climate engineering technology.
Roger Pielke Jr. points to the basic unfalsifiability of current climate models. If a lack of warming doesn't falsify predictions then what does that say about how we should treat the predictions?
I am sure that this is an excellent paper by world class scientists. But when I look at the broader significance of the paper what I see is that there is in fact nothing that can be observed in the climate system that would be inconsistent with climate model predictions. If global cooling over the next few decades is consistent with model predictions, then so too is pretty much anything and everything under the sun.
This means that from a practical standpoint climate models are of no practical use beyond providing some intellectual authority in the promotional battle over global climate policy. I am sure that some model somewhere has foretold how the next 20 years will evolve (and please ask me in 20 years which one!). And if none get it right, it won't mean that any were actually wrong. If there is no future over the next few decades that models rule out, then anything is possible. And of course, no one needed a model to know that.
Global warming might well be a big real problem coming up on us. But science is about predicting behavior. If we can understand a system well enough in theory our model of that system ought to allow us to make accurate predictions about it. Well, climate models can't do that.
The development of climate models is a very worthwhile human endeavor. But we can't use climate models to decide what to do about global warming because those models are highly inaccurate and unverifiable.
Update: A Some months back a highly accomplished planetary scientist of my acquaintance (whose aversion to politicized science debates is strong enough that he doesn't want to be quoted by name unfortunately) explained to me that he sees science as the ability to predict. He thinks the sources of error remaining in existing climate models are so large that these models aren't predictive.
The models are going to get better. But unless you happen to have a Ph.D. in atmospheric physics (or, far better, a time machine) it is going to be hard to know when the models cross over into high accuracy. Even once the models get really good we won't know until some time has gone by so that we can see that they really predict. Even then their results will still need to be stated with qualifiers such as "assuming total solar radiation doesn't change much" unless we develop the ability to accurately forecast future output of the sun.
I see the climate change models as having problems similar to the Reagan era Star Wars (Strategic Defense Initiative or SDI) program when computer scientist David Parnas opined that there was no way to verify the correctness of the software that would control the anti-missile defense system. How to prove the correctness of the models? This is a very serious question. Verification and validation of software is hard. For climate models it is especially hard because the systems that the models seek to simulate are not sufficiently well understood, the systems have chaotic effects, and our computers do not have enough capacity. Plus, we can't know what correct outputs look like without using a time machine.
We end up needing to just decide that since CO2 causes more heat to be retained that higher CO2 means a substantial probability of warming which melts Antartica and Greenland ice and floods lots of land. We ought to do something to be on the safe side not because we can prove a future disaster but rather because it is just some unknown but probably substantial probability. That's a harder sell than the absolute certainty that you'll hear from the likes of Al Gore.
In a way the debate between elites in Europe and the United States on global warming is irrelevant. China has sailed past the United States in CO2 emissions and that gap is only going to grow larger in future years. The Chinese aren't going to restrain their CO2 emissions. They want economic growth. Even in Western Europe the voting publics have shown an aversion to severe sacrifice to cut back on CO2 emissions. 50 coal electric plants are coming on line in Europe in the next 5 years even as Germany maintains its commitment to phase out nuclear electric power.
Over the next five years, Italy will increase its reliance on coal to 33 percent from 14 percent. Power generated by Enel from coal will rise to 50 percent.
And Italy is not alone in its return to coal. Driven by rising demand, record high oil and natural gas prices, concerns over energy security and an aversion to nuclear energy, European countries are expected to put into operation about 50 coal-fired plants over the next five years, plants that will be in use for the next five decades.
In the United States, fewer new coal plants are likely to begin operations, in part because it is becoming harder to get regulatory permits and in part because nuclear power remains an alternative.
Before you cry out that Euroes do far more than ugly polluting Americans (who are more opposed to coal pollution than are Europeans probably because Americans have higher living standards) keep in mind that European nations have still done far less than needed if we accept some of the more pessimistic IPCC forecasts and arguments about the resulting deleterious effects. Also, looks to me that they've reached the political limits of how much they'll sacrifice.
In a nutshell, people aren't going to sacrifice very much and the number of people who are consuming fossil fuels goes up every year and the average amount of fossil fuels consumed per person goes up every year. Asian industrialization swamps all other effects.
Since a lack of willingness to sacrifice and the difficulty in proving what CO2 build-up will do to temperatures I think we need to approach the problem differently. Admit there is a risk of warming and resulting risks of flooding, crop failures, and other problems. But also admit that humans aren't going to inflict major sacrifices on themselves to do much about it. The big surge in Prius sales is coming mostly from high oil prices, not due to concern about the Greenland ice mass. Though you can expect many Prius buyers to try to claim higher status due to their supposed environmental consciousness.
So what to do? Accelerate the development of technologies for getting energy from non-fossil fuels sources. Also, develop technologies for climate engineering.
Former BBC science journalist and astrophysicist Dr. David Whitehouse says in spite of rising atmospheric CO2 the average temperate on planet Earth is not rising.
With only few days remaining in 2007, the indications are the global temperature for this year is the same as that for 2006 – there has been no warming over the 12 months.
But is this just a blip in the ever upward trend you may ask? No.
The fact is that the global temperature of 2007 is statistically the same as 2006 as well as every year since 2001. Global warming has, temporarily or permanently, ceased. Temperatures across the world are not increasing as they should according to the fundamental theory behind global warming – the greenhouse effect. Something else is happening and it is vital that we find out what or else we may spend hundreds of billions of pounds needlessly.
Whitehouse is not making a radical claim. He's just not putting the same spin on the facts that you'll find in most media reports about temperature trends. A recent BBC report (not by Whitehouse) has a chart showing 1998 was warmer than any year since and 6 years in that period were slightly warmer than 2007. Their spin is that the 2007 temperature shows that global warming is a confirmed trend. Um, well, on one hand 2007 didn't return the world to cooler temperature levels from earlier decades. But on the other hand the amount of carbon dioxide in the atmosphere has gone up a lot since 1998. So why hasn't the average global temperature for 2007 easily beat the 1998 number? (not trying to imply an answer btw - I'm just full of questions)
Something is happening to our Sun. It has to do with sunspots, or rather the activity cycle their coming and going signifies. After a period of exceptionally high activity in the 20th century, our Sun has suddenly gone exceptionally quiet. Months have passed with no spots visible on its disc. We are at the end of one cycle of activity and astronomers are waiting for the sunspots to return and mark the start of the next, the so-called cycle 24. They have been waiting for a while now with no sign it's on its way any time soon.
So maybe atmospheric carbon dioxide (CO2) buildup really has a warming effect. But that warming effect is getting offset by a cooling effect caused by less solar radiation.
But recently the Sun's internal circulation has been failing. In May 2006 this conveyor belt had slowed to a crawl – a record low. Nasa scientist David Hathaway said: "It's off the bottom of the charts... this has important repercussions for future solar activity." What's more, it's not the only indicator that the Sun is up to something.
Back during the Little Ice Age era (starting perhaps as early as the 13th century and ending in the 19th century) the Earth experienced periods of reduced sunspot activity including during the Sporer Minimum (1450–1540) and Maunder Minimum (1645-1715). That period featured a Thames River that froze over in winters and lots of hunger and death from food shortages in Europe. Another Little Ice Age would cause problems on a scale rivaling or exceeding some of the problems predicted from global warming.
Reduced sunspot activity isn't necessarily a reason for complaisance about atmospheric CO2 buildup. Even if our pollution is buffering the effects of reduced solar output at some point the sun will probably kick back up again and the CO2 will still be there. Though if the Sun causes huge climate changes (and that appears to be the case) then we need to develop the means to rapidly dial up and down the greenhouse effect in order to reduce the size of climate swings caused by solar output fluctuations.
Another possibility: Maybe increased sulfur aerosol pollution from China burning more coal is generating a cooling effect that is partially canceling the warming effect of CO2 buildup. This seems plausible at least. China's rate of expansion has caused a huge increase in a wide range of emissions and not just CO2 emissions.
Along with aluminum and cement, steel is the biggest reason China added 90 gigawatts of power generation capacity this year, the third year in a row in which it will increase its power output by more than the total capacity of Britain. About 85 percent of those new power plants burn coal.
The International Energy Agency, an energy policy and research group in Paris, had predicted as recently as a few years ago that China's carbon emissions would not reach those of the United States until 2020. But industrial production and coal use have grown so much faster than estimated that the agency now thinks China took the lead this year.
Production which has been shifted from the West to China (many economists call this "free trade") is cheaper in China in part because China tolerates far more pollution per unit of production.
A study by researchers at Carnegie Mellon University found that if all the goods that the United States imported between 1997 and 2004 had been produced domestically, America's carbon emissions would have been 30 percent higher.
A separate study for the European Parliament examined the transfer of steel production to China from Germany. It found that China's less efficient steel mills, and its greater reliance on coal, meant that it emitted three times as much carbon dioxide per ton of steel as German steel producers.
Pollution has not only shifted to China, in other words, but intensified even faster than the country's rapidly expanding output.
So types of pollutants that reflect away the sun's energy are another possible explanation for the seeming end of the warming trend in Earth average temperature. Aside: Britain is also in the ranks of countries that have basically exported a lot of their pollution to China.
Update: What I want to know: How noisy is the data for measuring the average temperature of the Earth's atmosphere? Could noise in the data make a real warming trend seem to stop? Given that temperature over a period of centuries varies a great deal naturally one should expect natural trends to sometimes work with and work against human-caused trends and therefore make human-caused trends harder to detect and confirm. There are real limits on our ability to know what is going on.
Update II: See the comments section for a comment about how volcanic eruptions make the temperature data noisy. Also, Peak Coal might end the whole fossil fuels emissions debate in a couple of decades. Peak Oil and Peak Natural Gas will probably happen sooner. For more on Peak Coal see here and here and here and here.
It now appears that the estimates will never get much better. The reason lies with feedbacks in the climate system. For example, as the temperature increases, less snow will be present at the poles. Less snow means less sunlight reflected back into space, which means more warming.
Lucky (or unlucky) for us, I think we are going to run out of oil before we can melt the polar ice caps. The (not very accurate) models that assume big atmospheric carbon dioxide increases in the 21st century are making an unrealistic assumption. The big run-up in oil prices is signalling the coming end of the oil era. We should move past the oil era debates and start focusing on how to move more easily into the post-fossil fuels era.
“About 1/3 of the CO2 from fossil-fuel burning is absorbed by the world’s oceans,” explained lead author Ken Caldeira from the Carnegie Institution Department of Global Ecology. “When CO2 gas dissolves in the ocean it makes carbonic acid which can damage coral reefs and also hurt other calcifying organisms, such as phytoplankton and zooplankton, some of the most critical players at the bottom of the world’s food chain. In sufficient concentration, the acidity can corrode shellfish shells, disrupt coral formation, and interfere with oxygen supply. ”
Most of the research today points to a future where, in the absence of a major effort to curtail carbon dioxide emissions, there will be double the atmospheric concentrations of CO2 (760 parts per million, or ppm) by century’s end. Atmospheric carbon dioxide concentrations could reach 500 ppm by mid-century. Pre-industrial concentrations, by comparison, were 280 ppm and today's concentration is about 380 ppm.
The acidity from CO2 dissolved in ocean water is measured by the pH scale (potential of Hydrogen). Declines in pH indicate that a solution is more acidic. The U.S. Environmental Protection Agency  Quality Criteria for Water state: “For open ocean waters where the depth is substantially greater than the euphotic zone, the pH should not be changed more than 0.2 units outside the range of naturally occurring variation …” The euphotic zone goes to a depth of about 650 feet (200 meters), where light can still reach and photosynthesis can occur.
“Atmospheric CO2 concentrations need to remain at less than 500 ppm for the ocean pH decrease to stay within the 0.2 limit set forth by the U.S. Environmental Protection Agency ,” remarked Caldeira. “If atmospheric CO2 goes above 500 ppm, the surface of the entire ocean will be out of compliance with EPA pH guidelines for the open ocean. We need to start thinking about carbon dioxide as an ocean pollutant. That is, when we release carbon dioxide to the atmosphere, we are dumping industrial waste in the ocean.”
I have previously argued that since we can easily cool the Earth (even cause an Ice Age for less than $1 billion per year) using either silicon dioxide or dimethyl sulfide (DMS) that the main problem with atmospheric CO2 build-up the dissolving of atmospheric CO2 into the oceans making them too acidic. I've yet to come across any proposed methods for preventing ocean acidification. Also, it is not clear how much harm to marine life will come from a shift of pH down by 0.2.
Atmospheric CO2 might never reach 500 ppm. The rising cost of oil extraction will combine with future declines in the costs of nuclear and solar power to cause a shift away from fossil fuels and toward energy sources which are not net producers of carbon dioxide emissions.
The rabbit-proof fence — or bunny fence — in Western Australia was completed in 1907 and stretches about 2,000 miles. It acts as a boundary separating native vegetation from farmland. Within the fence area, scientists have observed a strange phenomenon: above the native vegetation, the sky is rich in rain-producing clouds. But the sky on the farmland side is clear.
Within the last few decades, about 32 million acres of native vegetation have been converted to croplands west of the bunny fence. On the agricultural side of the fence, rainfall has been reduced by 20 percent since the 1970s.
The article lists a few hypotheses for why this has happened. But the real interesting thing about this is what it portends for the future. As population growth and rising affluence increase the demand for food more land will get worked by farmers. Will this cause droughts? Will increased farming of land reduce rain enough to cause a reduction in total production in areas which become the most heavily farmed?
The human footprint on the Earth grows larger every year. Think about it.
Space scientist James Hansen, head of NASA's Goddard Institute for Space Studies, fears a runaway glacier melting scenario where sea levels will rise 5 meters.
The current rate of sea level change is not without consequences. However, the primary issue is whether global warming will reach a level such that ice sheets begin to disintegrate in a rapid, non-linear fashion on West Antarctica, Greenland or both. Once well under way, such a collapse might be impossible to stop, because there are multiple positive feedbacks. In that event, a sea level rise of several metres at least would be expected.
As an example, let us say that ice sheet melting adds 1 centimetre to sea level for the decade 2005 to 2015, and that this doubles each decade until the West Antarctic ice sheet is largely depleted. This would yield a rise in sea level of more than 5 metres by 2095.
Of course, I cannot prove that my choice of a 10-year doubling time is accurate but I'd bet $1000 to a doughnut that it provides a far better estimate of the ice sheet's contribution to sea level rise than a linear response. In my opinion, if the world warms by 2 °C to 3 °C, such massive sea level rise is inevitable, and a substantial fraction of the rise would occur within a century. Business-as-usual global warming would almost surely send the planet beyond a tipping point, guaranteeing a disastrous degree of sea level rise.
I see this outcome as unlikely for a few reasons:
I'm not worried about global warming. I am worried about Peak Oil. Our future must be driven by electric power (and we can generate that electric with nukes, solar panels or wind turbines). But we aren't far enough along in the development of the batteries we need to replace most liquid fuel used in transportation. The transition period off of fossil fuels could therefore feature some really deep wrenching global recessions as economies reorder to deal with declining oil production. At the risk of boring long time readers, batteries are the key technology of our energy future.
A team of international researchers has collected the oldest ever recovered DNA samples and used them to show that Greenland was much warmer at some point during the last Ice Age than most people have believed.
The ancient DNA was discovered at the bottom of a two kilometer thick ice sheet and came from the trees, plants and insects of a boreal forest estimated to be between 450,000 and 900,000 years-old. Previously, the youngest evidence of a boreal forest in Greenland was from 2.4 million years ago.
Natural trends will some day make Greenland much warmer than it is today.
Southern Greenland used to really be green.
The DNA samples suggest the temperature of the southern Greenland boreal forests 450,000 to 900,000 years-ago was probably between 10C in summer and -17C in winter. Also, the reduced glacier cover in that region means the global ocean was probably between one and two metres higher during that time compared to current levels.
Researchers analysed ice cores from a number of locations in Greenland, including Dye 3 in the south of the country. From the base of the 2km deep Dye 3 core, they were able to extract what they believe is likely to be the oldest authenticated DNA obtained to date.
By analysing these DNA samples, the researchers identified a surprising variety of plant and insect life, including species of trees such as alder, spruce, pine and members of the yew family, as well as invertebrates related to beetles, flies, spiders, butterflies and moths. The researchers believe that the samples date back to between 450,000 and 800,000 years ago.
Suppose humanity still exists the next time natural trends cause a major warming of the planet. Should humans seek to prevent the natural warming? Suppose the natural warming will be greater than the human-caused warming that some climate models predict as a result of human burning of fossil fuels. Should we intervene to stop a natural trend that will cause rising ocean levels and expansion and contraction of many ecological niches? Should we seek to save the polar bear from extinction due to natural climate change?
The global warming debate has focused on carbon dioxide emissions, but scientists at UC Irvine have determined that a lesser-known mechanism – dirty snow – can explain one-third or more of the Arctic warming primarily attributed to greenhouse gases.
If this is true it suggests we can greatly reduce ice melting by cutting back on particulates pollution from burning coal and other fossil fuels. Cutting back on the particulates would also reduce health harm from particulates. One of my recurring arguments on energy and environmental policy is that we should cut back on conventional air pollutants as a higher priority than reduction of carbon dioxide emissions. Here's evidence that cleaner burning of fossil fuels will reduce temperatures in the Arctic.
Snow becomes dirty when soot from tailpipes, smoke stacks and forest fires enters the atmosphere and falls to the ground. Soot-infused snow is darker than natural snow. Dark surfaces absorb sunlight and cause warming, while bright surfaces reflect heat back into space and cause cooling.
“When we inject dirty particles into the atmosphere and they fall onto snow, the net effect is we warm the polar latitudes,” said Charlie Zender, associate professor of Earth system science at UCI and co-author of the study. “Dark soot can heat up quickly. It’s like placing tiny toaster ovens into the snow pack.”
The study appears this week in the Journal of Geophysical Research.
The rapid rate at which China is building coal-fired electric power plants (1-2 per week) suggests the snow is going to get even more soot-infused in coming years.
Our snow is too dirty.
In the past two centuries, the Arctic has warmed about 1.6 degrees. Dirty snow caused .5 to 1.5 degrees of warming, or up to 94 percent of the observed change, the scientists determined.
Forest fires also generate soot that lowers albedo and heats up snow in the Arctic.
The Chinese aren't going to shift away from coal toward cleaner energy sources until the alternatives drop in price. However, as their living standards increase we can expect they will try harder to reduce emissions from their coal burning industries as their higher affluence causes them to see cleaner air as a higher priority. But their living standards have a long way to rise before they'll want to treat emissions controls as a high priority.
Will rise in atmospheric carbon dioxide (CO2) and consequent warming cause massive droughts and famine? Maybe not.
What goes up, must come down. This basic rule of gravity on Earth's surface also applies to water vapor in the atmosphere. And as the air, earth and sea warms with climate change the atmospheric water vapor load increases by as much as 6.5 percent per degree Celsius, according to satellite data from the past 20 years. As the water vapor increases, so, too, will rainfall, argues physicist Frank Wentz, director of Remote Sensing Systems (RSS) in Santa Rosa, Calif., a provider of climate data records contracted by NASA.
While global climate models predict less wind due to global warming Wentz and colleagues found that surface winds increased with recent warming. Winds will blow evaporated water from the oceans over land and hence winds create the potential for increased precipitation if the planet warms further.
But climate models project that global warming will also bring weaker winds, leading to less water evaporating from the ocean and counteracting the effect of warming. Models predict that worldwide precipitation — which must match the amount of evaporation — will increase by only 1-3% for each degree of future global warming.
They report in Science that the amount of water in the atmosphere, evaporation and precipitation all increased at the same rate, by about 1.3% per decade1 — or about 6.5% for every degree of warming. Surface winds increased, not decreased, with warming.
Why is this important: The "Apocalypse Soon" global warming doomsters predict global warming will lead to reduced precipitation and therefore crop failures and massive hunger. The official view of all Correct Thinking people is that global warming means massive droughts.
In February, the Intergovernmental Panel on Climate Change (IPCC) cited studies showing "extreme drought increasing from 1% of present-day land area to 30% by the end of the century."
The new study suggests models are flawed, underestimating how increased humidity in a warmer climate produces more rain clouds, Wentz said by e-mail.
Gavin Schmidt, a climatologist at the NASA Goddard Institute points out that the 20 years studied were dominated by a couple of El Niño events, which increased precipitation during that time. "The trends are not really significant," he says. "I think some more work would be necessary to really pin their argument down."
But if the warming brings more rain then more land might become usable for crops - especially lands closer to the north and south poles. Areas closer to the poles will gain longer growing seasons as nights get warmer in fall and spring and frost stops sooner and starts later. Massive farms in Siberia, Alaska, and northern Canada anyone?
Of course, that doesn't mean that a large increase in world temperatures will deliver net benefits. If Antarctica mostly melts then land areas will shrink due to rising ocean levels. Though we could build dikes to hold back the water ala Holland. Not sure that is feasible for Florida though. A cheaper solution for that problem: cool the poles with climate engineering to keep all the snow and ice frozen.
What worries me most about rising atmospheric CO2: Acidification of the ocean. That seems like a much tougher problem to prevent. Any ideas on that?
Alexander Ruzmaikin and Joan Feynman of NASA's Jet Propulsion Laboratory, Pasadena, Calif., together with Dr. Yuk Yung of the California Institute of Technology, Pasadena, Calif., have analyzed Egyptian records of annual Nile water levels collected between 622 and 1470 A.D. at Rawdah Island in Cairo. These records were then compared to another well-documented human record from the same time period: observations of the number of auroras reported per decade in the Northern Hemisphere. Auroras are bright glows in the night sky that happen when mass is rapidly ejected from the sun's corona, or following solar flares. They are an excellent means of tracking variations in the sun's activity.
If these cycles really are linked to climate variation it raises the obvious question of where we are right now in both those cycles.
The researchers found some clear links between the sun's activity and climate variations. The Nile water levels and aurora records had two somewhat regularly occurring variations in common - one with a period of about 88 years and the second with a period of about 200 years.
The researchers said the findings have climate implications that extend far beyond the Nile River basin.
We could engage in activities that are counter-cyclical. For example, emit more greenhouse gases when the sun's output is going down and take measures to reflect away sunlight when the sun's output is increasing. Are our CO2 emissions working countercyclically right now? Or are they reinforcing a trend of increasing solar output?
What'd I'd do if it was up to me to make climate engineering decisions for the Earth: Make Antarctica as cold as possible and direct moist clouds toward it. Try to tie up as much water as possible in Antarctica while simultaneously letting the northern hemisphere warm up. That way more total land mass would become usable for humans, plants, and animals while water levels in the ocean could be kept down or even lowered so that even more land becomes available. Some big ocean boosters will object to this strategy. I'm a land chauvinist. I stand in opposition to the ocean chauvinists. The oceans are hogging too much of the Earth's surface.
More than three-quarters of the particulate pollution known as black carbon transported at high altitudes over the West Coast during spring is from Asian sources, according to a research team led by Professor V. Ramanathan at Scripps Institution of Oceanography, UC San Diego.
With the Chinese putting 1 to 2 new coal burning electric plants online per week this problem is going to get much worse before it gets better. To repeat an argument I've made before: We need to accelerate the rate of advance of non-fossil fuels energy sources (primarily nuclear, solar, and wind). Only technological advances can make those energy sources become cheap enough that the Asians will want to switch to them and away from dirty fossil fuels. Populaces with lower living standards in less developed countries are less interested in the environment than they are in making more money. We can not expect them to take the same level of interest in reducing conventional pollutants as more affluent populations have.
Though the transported black carbon, most of which is soot, is an extremely small component of air pollution at land surface levels, the phenomenon has a significant heating effect on the atmosphere at altitudes above two kilometers (6,562 feet).
As the soot heats the atmosphere, however, it also dims the surface of the ocean by absorbing solar radiation, said Ramanathan, a climate scientist at Scripps, and Odelle Hadley, a graduate student at the Center for Atmospheric Sciences at Scripps. The two are lead authors of a research paper appearing in the March 14 issue of the Journal of Geophysical Research.
The researchers found that transported black carbon from Asian sources is equal to 77 percent of North American black carbon emissions in the troposphere during the spring.
The dimming at the ocean surface will reduce the rate of photosynthesis by algae. That'll reduce carbon dioxide uptake by plant photosyntheis and therefore reduce fish food supplies and fish stocks.
The soot is heating up the Pacific.
On a regional level, that amount of heating, or positive radiative forcing, the black carbon causes in the skies over the Pacific is about 40 percent of the forcing that has been attributed to the carbon dioxide increase of the last century, said Ramanathan. It likely has measurable effects on a variety of other physical and biological conditions in the areas of the Pacific over which the particulate pollution passes.
Also see my previous post about Asian air pollution's effects on cloud cover over the Pacific Ocean: Asian Air Pollution Changing Clouds. Plus, see my post China CO2 Emissions To Surpass US In 2009. The Kyoto Accord and similar climate change agreements will not accomplish much as long as the fossil fuels are cheaper than non-fossil fuel energy sources. The Asian economic juggernaut is radically reshaping the old world order where the United States and Europe were the two biggest users of energy and emitters of pollution.
Once living standards in a country get high enough people in that country start wanting to reduce pollution. The environmental movement did not take off in the United States in the 1960s because college students were taking LSD and mushrooms. The US reached a point where people had enough possessions that other desires and needs became important. Our problem with China, India, and other Asian countries is that they've rising emissions of pollutants from a few billion people with too many years to go before they reach living standards high enough to care about pollution control.
To put it another way: When the United States and Europe went through industrialization they had a lot fewer people doing the industrializing. First off, the US and Europe had a much smaller populations 100 years ago than they do today. Second, even today the US has a population less than a quarter of China's. India's population will reach 1.4 billion in 2025 and 1.6 billion by 2050 or more than 5 times America's population today. While elites in First World fully industrialized countries are worried about carbon dioxide emissions the Chinese and Indians haven't even graduated to the level of caring much about particulates and oxides of sulfur and nitrogen and the like. The quality of air in Chinese cities is getting worse as coal burning power plants get built at a frenetic pace.
I see this as a big and underappreciated problem for the future. Asian industrialization in such large populations pushes billions of people up into the ranks of polluters many years before they reach the ranks of yuppie environmentalists. Here's some new research on the effects that Asian air pollution is having on northern Pacific Ocean weather.
COLLEGE STATION – Severe pollution from the Far East is almost certainly affecting the weather near you, says a Texas A&M University researcher who has studied the problem and has published a landmark paper on the topic in the Proceedings of the National Academy of Sciences.
Renyi Zhang, professor of atmospheric sciences at Texas A&M and lead author of the paper, says the study is the first of its kind that provides indisputable evidence that man-made pollution is adversely affecting the storm track over the Pacific Ocean, a major weather event in the northern hemisphere during winter. The project was funded by the National Science Foundation and NASA.
Zhang says the culprit is easy to detect: pollution from industrial and power plants in China and India. Both countries have seen huge increases in their economies, which means more large factories and power plants to sustain such growth. All of these emit immense quantities of pollution – much of it soot and sulfate aerosols – into the atmosphere, which is carried by the prevailing winds over the Pacific Ocean and eventually worldwide.
Using satellite imagery and computer models, Zhang says that in roughly the last 20 years or so, the amount of deep convective clouds in this area increased from 20 to 50 percent, suggesting an intensified storm track in the Pacific.
Dr. Zhang is also concerned that soot could deposit on northern ice and snow, cause more sunlight absorption, and melting of the ice.
"The general air flow is from west to east, but there is also some serious concern that the polar regions could be affected by this pollution. That could have potentially catastrophic results."
Soot, in the form of black carbon, can collect on ice packs and attract more heat from the sun, meaning a potential acceleration of melting of the polar ice caps, he believes.
"It possibly means the polar ice caps could melt quicker than we had believed, which of course, results in rising sea level rates," he adds.
In November, the International Energy Agency projected that China will become the world's largest source of carbon dioxide emissions in 2009, overtaking the United States nearly a decade earlier than previously anticipated. Coal is expected to be responsible for three-quarters of that carbon dioxide.
And the problem will get worse. Between now and 2020, China's energy consumption will more than double, according to expert estimates.
The problem is that IGCC plants still cost about 10 percent to 20 percent more per megawatt than pulverized-coal-fired power plants. (And that's without carbon dioxide capture.) China's power producers--much like their counterparts in the United States and Europe--are waiting for a financial or political reason to make the switch. In part, what's been missing is regulation that penalizes conventional coal plants. And China's environmental agencies lack the resources and power to make companies comply even with regulations already on the books. Top officials in Beijing admit that their edicts are widely ignored, as new power plants are erected without environmental assessments and, according to some sources, without required equipment for pollution control.
I find the Western emphasis on Kyoto CO2 emissions reductions somehow quaint. It assumes we've moved on from worrying about already conquered problems with conventional ground level pollutants that directly harm health. But the environmental impact of Asian industrialization does not fit with that view.
Technologies that allow emissions reduction have already been developed in the West and those technologies keep getting better due to tightening environmental regulations in Western countries. So in theory China and India could adopt those technologies. But since those technologies raise costs use of them requires a willingness to pay a price. That price is obviously higher than they are willing to pay.
The Asian pollution problem highlights another reason why we'd benefit from the development of ways to cheaply generate energy without use of fossil fuels. If nuclear, solar, wind, and other energy technologies become cheaper than fossil fuels then the industrializing Asian countries would switch to these technologies without first achieving levels of per capita GDP high enough to trigger the development of large scale environmental movements.
Jerusalem, March 7, 2007 -- Manmade climate change due to pollution seriously inhibits precipitation over hills in semi-arid regions, a phenomenon with dire consequences for water resources in the Middle east and many other parts of the world, a study by a Chinese-Israeli research team, led by Prof. Daniel Rosenfeld of the Hebrew University of Jerusalem, has shown.
The Chinese and Israeli researchers showed that the average precipitation on Mount Hua near Xian in central China has decreased by 20 percent along with increasing levels of manmade air pollution during the last 50 years. The precipitation loss was doubled on days that had the poorest visibility due to pollution particles in the air. This explains the widely observed trends of decrease in mountain precipitation relative to the rainfall in nearby densely populated lowlands, which until now had not been directly ascribed to air pollution.
Industrialization in countries holding a few billion people creates environment problems on a scale which we have not seen previously. This comes on top of Western pollution.
Update II: An article from the June 11, 2006 New York Times illustrates the scale of China's pollution problems.
In early April, a dense cloud of pollutants over Northern China sailed to nearby Seoul, sweeping along dust and desert sand before wafting across the Pacific. An American satellite spotted the cloud as it crossed the West Coast.
Researchers in California, Oregon and Washington noticed specks of sulfur compounds, carbon and other byproducts of coal combustion coating the silvery surfaces of their mountaintop detectors. These microscopic particles can work their way deep into the lungs, contributing to respiratory damage, heart disease and cancer.
Filters near Lake Tahoe in the mountains of eastern California "are the darkest that we've seen" outside smoggy urban areas, said Steven S. Cliff, an atmospheric scientist at the University of California at Davis.
The same double digit percentage increase becomes a larger absolute increase each year. Then there's India.
Already, China uses more coal than the United States, the European Union and Japan combined. And it has increased coal consumption 14 percent in each of the past two years in the broadest industrialization ever. Every week to 10 days, another coal-fired power plant opens somewhere in China that is big enough to serve all the households in Dallas or San Diego.
To make matters worse, India is right behind China in stepping up its construction of coal-fired power plants — and has a population expected to outstrip China's by 2030.
When China reaches the same total GDP as the United States the Chinese will pollute far more than Americans because China will have much lower living standards per person. At that point China will have less than a quarter the per capita GDP and far less accumulated assets in the form of houses, cars, and gadgets. So Chinese people will be more interested in accumulating assets than in pollution reduction.
The positive correlation between living standards and interest in pollution reduction means we need to accelerate the development of energy technologies that are both cheaper and less polluting. Uptake of technologies that are both cleaner and cheaper does not require development of a big mass environmental protection movement in China and India. Market forces alone will drive the shift away from dirtier technologies.
Global warming would be much worse if the world had not put a halt to the destruction of the ozone hole above Antarctica, say researchers.
They say the 1987 Montreal Protocol, which restricts the use of CFCs and other ozone-depleting chemicals, will cut warming by five or six times more than the Kyoto Protocol.
The CFCs have made the ozone hole over the Antarctic much larger. Rapid economic growth in India and other Asian countries has slowed the decline in CFC emissions
For example, says atmospheric scientist Guus Velders of the Netherlands Environmental Assessment Agency in Bilthoven, the class of compounds known as chlorofluorocarbons (CFCs) traps 5000 to 14,000 times more heat, pound for pound, than carbon dioxide, and 400 times more heat than methane.
DuPont advocates an accelerated phaseout of HCFCs, actions to minimize emissions of refrigerants and adoption of low global warming potential (GWP) alternatives, where possible. Last year, the company announced the identification of a low GWP refrigerant for auto air conditioning applications and is currently working on leveraging this low GWP technology to other refrigerant applications.
This reminds me of a recent story on how rapid economic growth in India, China, and other Asian countries is delaying the recovery of the ozone layer by a quarter of a century.
Scientists mostly blame chlorofluorocarbons, a chemical used in an early form of refrigerant that they now realize was released into the atmosphere in larger quantities than forecast. As a result, the international agencies now say that injury to the Earth's ozone layer could take a quarter of a century longer to heal than previously expected.
The fastest-growing offending gas that scientists say can be better managed is HCFC-22. Nearly 200 diplomats will gather in September in Montreal to determine how to speed up the timetable for the elimination of certain gases that threaten the ozone layer, in particular how to manage HCFC-22. A deadline for proposals is March 15.
The cheapest way to reduce global warming is to accelerate the phaseout of CFCs and HCFCs. The Bush Administration is proposing a more accelerated phaseout of HCFCs. Sounds like a good idea.
More generally: Rapid Asian economic growth means that Western efforts to reduce CO2 emissions are going to get swamped by larger Asian increases in CO2 and other greenhouse gas emissions. We need to accelerate the development of solar, nuclear, and other non-fossil fuels energy technologies to lower their costs below the costs of fossil fuels. The Asians will shift toward non-fossil fuel energy sources if these sources are cheaper. Otherwise, expect more CO2 emissions.
A new report from FAO says livestock production contributes to the world's most pressing environmental problems, including global warming, land degradation, air and water pollution, and loss of biodiversity. Using a methodology that considers the entire commodity chain, it estimates that livestock are responsible for 18 percent of greenhouse gas emissions, a bigger share than that of transport. However, the report says, the livestock sector's potential contribution to solving environmental problems is equally large, and major improvements could be achieved at reasonable cost.
Based on the most recent data available, Livestock's long shadow takes into account the livestock sector's direct impacts, plus the environmental effects of related land use changes and production of the feed crops animals consume. It finds that expanding population and incomes worldwide, along with changing food preferences, are stimulating a rapid increase in demand for meat, milk and eggs, while globalization is boosting trade in both inputs and outputs.
Grazing uses a quarter of the land surface of the Earth. Think about what that means as populations increase and humans all over the world use rising affluence to move out into newly created suburbs. Land supplies are inadequate. The human race has gotten too big.
Deforestation, greenhouse gases. The livestock sector is by far the single largest anthropogenic user of land. Grazing occupies 26 percent of the Earth's terrestrial surface, while feed crop production requires about a third of all arable land. Expansion of grazing land for livestock is a key factor in deforestation, especially in Latin America: some 70 percent of previously forested land in the Amazon is used as pasture, and feed crops cover a large part of the reminder. About 70 percent of all grazing land in dry areas is considered degraded, mostly because of overgrazing, compaction and erosion attributable to livestock activity.
To the fans of biomass energy: Hasn't enough of the Amazon already been lost to pasture land? Do we need to make it worse by promoting the destruction of the rain forests in the name of biomass energy environmentalism?
Livestock are responsible for 37% of anthropogenic methane (i.e. methane produced as a result of human activities).
FAO estimated that livestock are responsible for 18 percent of greenhouse gas emissions, a bigger share than that of transport. It accounts for nine percent of anthropogenic carbon dioxide emissions, most of it due to expansion of pastures and arable land for feed crops. It generates even bigger shares of emissions of other gases with greater potential to warm the atmosphere: as much as 37 percent of anthropogenic methane, mostly from enteric fermentation by ruminants, and 65 percent of anthropogenic nitrous oxide, mostly from manure.
Methane is probably the biggest greenhouse gas problem with livestock. As a greenhouse gas methane is about 21 times more potent than carbon dioxide by weight. Rising world affluence translates into rising demand for meat and that means more cows, sheep, and other methane producers.
But methane from livestock strikes me as (at least in theory) a much more tractable problem than carbon dioxide from fossil fuels burning. The potential exists to capture dairy cow methane when they are in buildings. Also, feeds greatly differ in their effects on methane production and cow bacteria balances could be manipulated to lower methane production. Biotechnology could drastically cut back on livestock methane production.
The use of fossil fuels in agriculture is more problematic for the same reason that the use of fossil fuels is so intractable in other human activities. Until other energy sources become cheaper than fossil fuels the rising demand for livestock and fancier food in general is going to cause a rising demand for fossil fuels.Livestock compete with wild animals for land area. As the human race becomes more affluent the amount of animal biomass that will be wild is going to decline. This'll drive more species to extinction. (So will medical treatments that allow humans to live in high disease areas.)
The sheer quantity of animals being raised for human consumption also poses a threat of the Earth's biodiversity. Livestock account for about 20 percent of the total terrestrial animal biomass, and the land area they now occupy was once habitat for wildlife. In 306 of the 825 terrestrial eco-regions identified by the Worldwide Fund for Nature, livestock are identified as "a current threat", while 23 of Conservation International's 35 "global hotspots for biodiversity" - characterized by serious levels of habitat loss - are affected by livestock production.
The full text of the UN Food and Agricultural Organization report Livestock's long shadow is downloadable as a PDF file.
Elizabeth Economy, director for Asia studies at the Council on Foreign Relations, says China will surpass the United States in carbon dioxide emissions and China is embarked on an internal propaganda campaign to blame the rest of the world.
Last month the International Energy Agency announced that China would probably surpass the United States as the world's largest contributor of the greenhouse gas carbon dioxide by 2009, more than a full decade earlier than anticipated. This forecast could spur China to adopt tough new energy and environmental standards, but it probably won't. China has already embarked on a very different strategy to manage its environmental reputation: launching a political campaign that lays much of the blame for the country's mounting environmental problems squarely on the shoulders of foreigners and, in particular, multinational companies.
While still in its initial stages, the campaign has gained steam over the past month. Senior Chinese officials, the media and even some environmental activists have charged multinational firms and other countries with exporting pollution, lowering their environmental manufacturing standards and willfully ignoring China's environmental regulations. Faced with growing international and popular discontent over the country's environmental crisis, China's leaders are tapping into anti-foreign and nationalist sentiments to deflect attention from their own failures.
First off, China's not going to help. Second, if they are going to surpass the United States in 2009 then where are they going to be in 2019 or 2029?
Consider the sheer cheekiness of this claim:
In late October a top environmental official, Pan Yue, accused the developed countries of "environmental colonialism": of transferring resource-intensive, polluting industries to China and bearing as little environmental responsibility as possible.
The Chinese government is buying massive amounts of American debt in order to keep the Chinese yuan currency undervalued. This boosts Chinese exports and decreases production in other countries of steel and other energy-intensive products. As the US dollar has dropped against other currencies in response to a US trade deficit that East Asian countries created with US debt purchases it has made the Chinese currency even more undervalued against the Euro, the English Pound, and other currencies.
Benny Peiser points out the above article and this one below by Fiona Harvey, environment correspondent for the Financial Times as indications for why the current unilateral regulatory approach in Europe faces an increasingly difficult reception. Some of Europe's reduction in CO2 emissions has just shifted to other countries which levy fewer taxes on energy usage. Fiona Harvey says that countries are afraid to put higher costs on carbon dioxide emissions because they fear loss of international competitiveness.
Japan refused to hurry moves to commit to reductions in emissions beyond 2012, when the current provisions of the Kyoto protocol expire, because of fears that it would hand China a competitive advantage in manufacturing industries. Canada faced a similar dilemma, resisting pressure to push for greater emissions cuts as the US was refusing to take on reduction targets. The US and Australia have already rejected the protocol, which obliges developed countries to cut their emissions by an average of 5 per cent compared with 1990 levels by 2012.
More worrying for proponents of the treaty, however, are rifts on the issue that are beginning to become apparent within Europe. The European Union has long been the most steadfast supporter of the Kyoto protocol, in the face of backsliding from Canada and Japan. The EU was credited with enticing Russia to agree to the protocol two years ago, which was the decisive factor in ensuring the long-delayed agreement finally came into effect. The EU’s greenhouse gas emissions trading scheme is the only mandatory scheme in the world to impose constraints on business emissions of carbon dioxide and to allow companies to trade their emissions allowances with one another in order to reduce carbon output at the lowest possible price.
Governments aren't just worried about reduced competitiveness. Their publics do not want to pay more for energy and for products and services made from energy.
The Kyoto Accord to cut green house gas emissions wasn't honored by some of its signatories. Now the percentage of emissions by non-Kyoto countries is skyrocketing. An international agreement isn't going to cut total carbon dioxide (CO2) emissions or even slow CO2 emissions growth by much.
Worried about the potential for global warming? There's only one way to stop CO2 emissions growth: Development of energy technologies that are cleaner and cheaper than fossil fuels is the only way guaranteed to CO2 emissions.
Not only is the amount of carbon dioxide (CO2) getting pumped into the atmosphere increasing but the rate at which it is increasing is itself increasing. In the last 5 years the rate of growth in CO2 emissions was 5 times faster than it was in the 1990s.
The global growth in carbon dioxide emissions from fossil fuels was 4 times greater in the period between 2000 to 2005 than in the preceding 10 years, say scientists gathering in Beijing today for an international conference on global environmental change.
Despite efforts to reduce carbon emissions, the global growth rate in CO2 was 3.2% in the five years to 2005 compared to 0.8% in the period 1990 to 1999, according to data soon to be published by the Global Carbon Project (www.globalcarbonproject.org), a component of the Earth System Science Partnership (www.essp.org).
The industrialization of some high population countries is behind the acceleration in the rate of growth of CO2 emissions. China has now surpassed Japan and is the second largest fossil fuels user and CO2 emitter after the United States
One likely contributor is China, whose emissions slowed at end of the 1990s before rising again. China is now the world’s second largest emitter of greenhouse gases after the US. On Tuesday, the International Energy Agency released a report predicting that it would become the world’s top emitter by 2030 (see World faces 'dirty, insecure' energy future).
Other growing developing countries, such as India and Brazil, are also fast becoming large emitters.
Rapidly growing less developed countries aren't going to hold back their growth in order to stop the rise in CO2 emissions. Only the development of cheaper cleaner energy technologies can stop the rise of CO2 emissions.
To repeat: CO2 emissions will continue to rise rapidly until cheap technologies are developed that produce energy without emitting CO2.
Some argue that CO2 fluctuations over the Phanerozoic follow climate trends fairly well, supporting a causal relationship between high gas levels and high temperatures. “The geologic record over the past 550 million years indicates a good correlation,” said Robert A. Berner, a Yale geologist and pioneer of paleoclimate analysis. “There are other factors at work here. But in general, global warming is due to CO2. It was in the past and is now.”
Other experts say that is an oversimplification of a complex picture of natural variation. The fluctuations in the gas levels, they say, often fall out of step with the planet’s hot and cold cycles, undermining the claimed supremacy of carbon dioxide.
“It’s too simplistic to say low CO2 was the only cause of the glacial periods” on time scales of millions of years, said Robert Giegengack, a geologist at the University of Pennsylvania who studies past atmospheres. “The record violates that one-to-one correspondence.”
He and other doubters say the planet is clearly warming today, as it has repeatedly done, but insist that no one knows exactly why. Other possible causes, they say, include changes in sea currents, Sun cycles and cosmic rays that bombard the planet.
“More and more data,” Jan Veizer, an expert on Phanerozoic climates at the University of Ottawa, said, “point to the Sun and stars as the dominant driver.”
Paleoclimatology should get larger chunks of research money. We need to find out how much costs we should foist upon ourselves in order to reduce or perhaps even reverse the build up of atmospheric CO2 from fossil fuels burning. I'd hate to slow worldwide economic growth to solve a problem that might turn out to be much smaller than the gloomier forecasts make it out to be. But at the same time, I'd hate to underspend in solving a problem that is going to be far more expensive and disruptive than the optimists expect. Better information leads to better decisions.
We should also put more government research dollars into developing cleaner energy sources. That money will get paid back in the form of cheaper energy, cleaner environment down at ground level where we breathe and eat, and faster economic growth.
One of my disappointments with the pro-Kyoto Accord forces is that they do not push either increased climate history research spending or energy research spending anywhere near as hard as they push restriction of CO2 emissions now. It is like they want to choose the most painful path. But the opponents of the Kyoto Accord aren't, for the most part, trying to accelerate the development of greater knowledge about climate history or pushing for a big scale-up of energy research either. The deniers of the problem want to do nothing. The believers in the problem want to go down a path that is most punishing. How about a more rational middle?
The biggest potential problem with global warming would come if large amounts of water bound up in ice in Greenland and Antarctica melted and raised the seas. A pair of satellites show that the total amount of water locked up in Antarctica is shrinking.
University of Colorado at Boulder researchers have used data from a pair of NASA satellites orbiting Earth in tandem to determine that the Antarctic ice sheet, which harbors 90 percent of Earth's ice, has lost significant mass in recent years.
The team used measurements taken with the Gravity Recovery and Climate Experiment, or GRACE, to conclude the Antarctic ice sheet is losing up to 36 cubic miles of ice, or 152 cubic kilometers, annually. By comparison, the city of Los Angeles uses about 1 cubic mile of fresh water annually.
"This is the first study to indicate the total mass balance of the Antarctic ice sheet is in significant decline," said Isabella Velicogna of CU-Boulder's Cooperative Institute for Research in Environmental Sciences, chief author of the new study that appears in the March 2 online issue of Science Express. The study was co-authored by CU-Boulder physics Professor John Wahr of CIRES, a joint campus institute of CU-Boulder and the National Oceanic and Atmospheric Administration.
At the measured rate of melting it would take about 6 years for the oceans to rise an inch or 72 years to rise a foot.
The estimated ice mass in Antarctica is equivalent to 0.4 millimeters of global sea rise annually, with a margin of error of 0.2 millimeters, according to the study. There are about 25 millimeters in an inch.
The most recent Intergovernmental Panel on Climate Change assessment, completed in 2001, predicted the Antarctic ice sheet would gain mass in the 21st century due to increased precipitation in a warming climate. But the new study signals a reduction in the continent's total ice mass, with the bulk of loss occurring in the West Antarctic ice sheet, said Velicogna.
Researchers used GRACE data to calculate the total ice mass in Antarctica between April 2002 and August 2005 for the study, said Velicogna, who also is affiliated with the NASA's Jet Propulsion Laboratory in Pasadena.
"The overall balance of the Antarctic ice is dependent on regional changes in the interior and those in the coastal areas," said Velicogna. "The changes we are seeing are probably a good indicator of the changing climatic conditions there."
Launched in 2002 by NASA and Germany, the two GRACE satellites whip around Earth 16 times a day at an altitude of 310 miles, sensing subtle variations in Earth's mass and gravitational pull. Separated by 137 miles at all times, the satellites measure changes in Earth's gravity field caused by regional changes in the planet's mass, including such things as ice sheets, oceans and water stored in the soil and in underground aquifers.
A change in gravity due to a pass over a portion of the Antarctic ice sheet, for example, imperceptibly tugs the lead satellite away from the trailing satellite, said Velicogna. A sensitive ranging system allows researchers to measure the distance of the two satellites down to as small as 1 micron -- about 1/50 the width of a human hair -- and to then calculate the ice mass in particular regions of the continent.
The satellites enabled collection of data across the entire Antarctic.
"The strength of GRACE is that we were able to assess the entire Antarctic region in one fell swoop to determine whether it was gaining or losing mass," said Wahr. While the CU researchers were able to differentiate between the East Antarctic ice sheet and West Antarctic ice sheet with GRACE, smaller, subtler changes occurring in coastal areas and even on individual glaciers are better measured with instruments like radar and altimeters, he said.
A study spearheaded by CIRES researchers at CU-Boulder and published in September 2004 concluded that glaciers on the Antarctic Peninsula - which juts north from the West Antarctic ice sheet toward South America -- sped up dramatically following the collapse of Larsen B ice shelf in 2002. Ice shelves on the peninsula -- which has warmed by an average of 4.5 degrees Fahrenheit in the past 60 years -- have decreased by more than 5,200 square miles in the past three decades.
The thickness of the Antarctic ice averages well over a mile for the entire Antarctic. That's massive.
As Earth's fifth largest continent, Antarctica is twice as large as Australia and contains 70 percent of Earth's fresh water resources. The ice sheet, which covers about 98 percent of the continent, has an average thickness of about 6,500 feet. Floating ice shelves constitute about 11 percent of the continent.
The melting of the West Antarctic ice sheet alone - which is about eight times smaller in volume than the East Antarctic ice sheet -- would raise global sea levels by more than 20 feet, according to researchers from the British Antarctic Survey.
You can look at pretty pictures on the web.
Animation of the GRACE mission is available on the Web at http://www.csr.utexas.edu/grace/gallery/animations/. Images of Antarctic ice shelves are available from CU-Boulder's National Snow and Ice Data Center at: http://nsidc.org/data/iceshelves_images/.
What is most important about this study is that it used satellites to build a much more comprehensive picture of what is happening with the ice. The problem is that the satellites were launched only in 2002.
Richard Alley, a Pennsylvania State University glaciologist who has studied the Antarctic ice sheet but was not involved in the new research, said more research is needed to determine if the shrinkage is a long-term trend, because the new report is based on just three years of data. "One person's trend is another person's fluctuation," he said.
But Alley called the study significant and "a bit surprising" because a major international scientific panel predicted five years ago that the Antarctic ice sheet would gain mass this century as higher temperatures led to increased snowfall.
Scientists can't prove that human activities are causing global warming. However, humans are changing the atmosphere on a large enough scale that the possibility exists that we are changing the climate. In much of the world I do not see warming as a problem. In fact, for people living in such places as northern Russia, Finland, Alaska, Alberta, North Dakota, or Minnesota winter warming strikes me as pretty beneficial. But melting of the Antarctic ice would produce huge costs all over the world. Coastal lands are valuable. Large low lying areas would be lost. We'd simply have a lot less land and the fishies would have a lot more water to swim in if a substantial portion of Antarctica's ice melted.
The biggest problem we have with the climate debate is that the big mathematical models can't predict what'll really happen since the models contain simplifications that are probably wrong in important ways. We end up having to guess what will happen. Nature continually makes the climate change even without humans getting involved. So even once a change has happened it is still impossible to figure out how much of the change was caused by humans.
It seems to me we ought to approach this problem by first realizing we need greater capabilities. and that we need greater capabilities in several areas:
Writing in the journal Nature today, scientists at the Meteorological Office and the US government's National Oceanic and Atmospheric Administration report that climate models used to predict future global warming have badly underestimated the cooling effect of aerosols.
"We found that aerosols actually have twice the cooling effect we thought," said Nicolas Bellouin, a climate modeller at the Met Office. The consequence is that as air quality improves and aerosol levels drop, future warming may be greater than we currently think."
Pollutants are a source of aerosols that have been decreased by environmental regulations - at least in the more industrialized countries. A decline in pollutant aerosols might cause a much higher level of global warming.
The group has produced the most precise estimates yet of how tiny particles, known as aerosols, could affect the world's climate. Aerosols, which include pollutants, have a cooling effect on the atmosphere, and the team's work suggests that the cooling effect is strong - nearly as strong as the top estimates of the United Nation's Intergovernmental Panel on Climate Change (IPCC).
Thus, the dwindling presence of aerosols means that global average temperatures could rise faster than previously estimated and reach toward the high end of projections for the end of the century.
Those estimates currently range from 2.7 to 7.9 degrees F., depending on how emissions of greenhouse gases and other factors play out in coming years.
The second article says some of the effects of aerosols still haven't been puzzled out. So the story could change. But suppose the aerosol effect turns out to be as these researchers say. Would it be possible to come up with an artificial aerosol that would have no negative health impacts yet which could lower the Earth's temperature? If such an aerosol was discovered would environmentalists oppose its widespread release?
There's an interesting angle to this report that I haven't seen reported: Rapid economic growth in China is greatly boosting particulate emissions from coal burning. But when living standards in China rise far enough the population will start demanding cleaner air. At that point a decline in Chinese aerosol emissions would happen under much higher atmospheric CO2 conditions. This could cause a temperature spike at that point.
You can read the Nature abstract here.
Two new studies of gases trapped in Antarctic ice cores have extended the record of Earth’s past climate almost 50 percent further, adding another 210,000 years of definitive data about the makeup of the Earth’s atmosphere and providing more evidence of current atmospheric change.
The research is being published in the journal Science by participants in the European Project for Ice Coring in Antarctica. It’s "an amazing accomplishment we would not have thought possible" as recently as 10 years ago, said Ed Brook, a professor of geosciences at Oregon State University, who analyzed the studies in the same issue of this professional journal.
"Not long ago we thought that previous ice studies which go back about 500,000 years might be the best we could obtain," said Brook, who is also the co-chair of the International Partnerships in Ice Coring Sciences, a group that’s helping to plan future ice core research efforts around the world.
650,000 years is a long time to have such a history of the Earth's' atmosphere's constituents. But the scientists now think they can go back further than 1 million years.
"Now we have a glimpse into the past of up to 650,000 years, and we believe it may be possible to go as much as one million years or more," Brook said. "This will give us a fuller picture of Earth’s past climates, the way they changed and fluctuated, and the forces that caused the changes. We’ll be studying this new data for years."
As the data become more solid about the atmospheric conditions of the past, it’s becoming increasingly clear that the current conditions of the past 200 years are a distinct anomaly, Brook said."The levels of primary greenhouse gases such as methane, carbon dioxide and nitrous oxide are up dramatically since the Industrial Revolution, at a speed and magnitude that the Earth has not seen in hundreds of thousands of years," Brook said. "There is now no question this is due to human influence."
Humans have created atmospheric conditions unlike any seen in the last 650,000 years. That ought to give anyone pause. We should be concerned about what this portends for the future. It could be good. Or it could be bad. It will certainly be different. Shouldn't we at least be trying a lot harder to develop energy technologies that do not use fossil fuels?
Last night I was watching an excellent History Channel TV show about climate changes on the Earth from the early Middle Ages to today. The warming period that preceded the 14th century cooling was an amazing period. Food production surged. Fish populations surged near Europe. Grapes for wine were grown in Britain 300 miles north of where grapes are grown in France today. Europe's population surged by 50%. Swamps dried out and this led to a big decrease in malaria. Climate change is not necessarily automatically bad in its effects.
However, that warming might have triggered a flow of melting glacial water into the North Atlantic that then caused the Atlantic Conveyor to stop bringing warm water up from the south and that might have triggered the cooling that started in the 14 century (said cooling had the River Thames freezing solid every winter in England). But then again, that cooling might have been caused by volcanic eruptions, lower solar output, and other natural phenomena. The take-home lesson I got from the show was that if you have had fairly stable climate for a few centuries then best you start expecting a big shift. The climate is just not stable for many centuries running.
EPICA is the European Project for Ice Coring in Antarctica. The new ice core, initially described in 2004, is from a site in East Antarctica known as EPICA Dome C. This work represents a long-term European research collaboration and appears in two studies and an accompanying “Perspective” article in the 25 November 2005 issue of the journal Science, published by AAAS the nonprofit science society.
One study chronicles the stable relationship between climate and the carbon cycle during the Pleistocene (390,000 to 650,000 years before the present). The second one documents atmospheric methane and nitrous oxide levels over the same period.
The analysis highlights the fact that today’s rising atmospheric carbon dioxide concentration, at 380 parts per million by volume, is already 27 percent higher than its highest recorded level during the last 650,000 years, said Science author Thomas Stocker of the Physics Institute of the University of Bern, in Bern, Switzerland, who serves as the corresponding author for both papers.
I do not favor immediate regulations on CO2 emissions that would put a big damper on global economic growth. However, the continued rise in CO2 emissions really ought to be reason for serious concern by all prudent and rational people. We do not know what this rise in CO2, methane, and other greenhouse gassess is going to do to the global climate system. We really ought to make a very large push to develop technologies that would allow us to generate large amounts of cheap energy from non-fossil fuels energy sources.
The human-caused changes in the atmosphere have been made in a short period of time as compared to the length of most natural climate cycles.
“We have added another piece of information showing that the timescales on which humans have changed the composition of the atmosphere are extremely short compared to the natural time cycles of the climate system,” Stocker explained.
Though the recorded record made by humans does contain incidents of large climate changes that came on within the space of a single year. So the climate does sometimes shift very rapidly.
A half million years ago the interglacials were warmer and longer lasting.
The new work confirms the stable relationship between Antarctic climate and the greenhouse gasses carbon dioxide and methane during the last four glacial cycles. The new ice core analysis also extends this relationship back another two glacial cycles, to a time when the warm “interglacial” periods were milder and longer than more recent warm periods, according to the European researchers.
The fact that carbon dioxide and methane levels were lower during the relatively mild warm periods of the two additional cycles, compared to the warmer warm periods of the last 400,000 years, is especially interesting for the study of climate sensitivity, which is a measure of how the climate system reacts when atmospheric carbon dioxide concentrations double, explained Science author Dominique Raynaud from LGGE in Grenoble, France.
The new atmospheric and climate records from the EPICA Dome C ice core also indicate that the response of the natural carbon cycle to climate warming remains the same over time – in terms of the mechanism involved and the degree to which greenhouse gasses further amplify climate change, explained Science author Jean Jouzel from LSCE and Institut Pierre Simon Laplace in France.
Recent interglacial warming periods have been only 10,000 or so years long. Worryingly, we are already 10,000 years into the current interglacial. Anyone feel a chill coming on?
The new ice core analysis provides insights on our present interglacial warm period through a glimpse into Antarctic climate and greenhouse gas concentrations during the most recent warm period that is relatively similar to our current warm period. Known as Marine Isotope Stage 11 or MIS 11, this analog warm period occurred between 420,000 and 400,000 years and is not completely covered by the Vostok record.
The similarities between our current warm period and MIS 11 are primarily due to a similar configuration of the orbits of the Earth around the Sun: the relative positions of the Earth and Sun are thought to be the key driver of ice age cycles.
On an optimistic note, the MIS 11 warming period which was during a period with a similar orientation between the Earth and Sun wasted at least 20,000 years and so maybe we don't face an massive cooling any time soon.
“MIS 11 shows us that the climate system can indeed reside in a warm period for 20,000 or 30,000 years, something that we can’t say based on the last three warm phases which are no longer than about 10,000 years each,” said Stocker.
We are currently about 10,000 years into our current warm period.
The new papers also document MIS 13 and 15 -- two warm periods more distant than MIS 11 that may have been about as long. The idea that MIS 13 and 15 were long warm periods contrasts the argument scientists have made in the past suggesting that our current warm period is exceptionally long.
Sooner or later natural processes will kick the Earth's climate into a state greatly changed from what it is today. When that happens do you favor or oppose measures to engage in massive scale climate engineering to dampen the extent of the changes either locally or globally?
For example, suppose a big warming took place. Would you favor cloud seeding over Greenland to increase snow build-up as a way to reduce melting of the Greenland ice pack? Or would you prefer to see much of Bangladesh and south Florida submerged under rising ocean waters?
Or suppose we were hit by a half percent decrease in solar energy output similar to that which happened during the Maunder Minimum of 1645 to 1715 where the decrease in sun spot activity reduced solar output and deepened an existing cooler period. Suppose at the same time we were hit by a massive volcanic eruption or even a few of them and the sulfur in the atmosphere helped cause an even deeper cooling with snow falling in New England during June and July. I'm describing a period of history that happened just a few hundred years ago. So such a scenario is not far-fetched or improbable.
Given a big cooling would you oppose or support making all buildings and roads black so that they absorbed more light energy? Or if this happens 50 years from now and we have cheap space launch at that point would you oppose or support the launching of a satellite system of reflectors to aim more light at some part of the Earth to warm it up?
My take on the climate is that it is not as stable as is widely believed. We ought to expect change just from natural processes. Throw in our own increasing effects on the atmosphere and we ought to have an even greater expectation of change. This view makes me think we need better tools for adapting to climate changes. Certainly we need more rapid development of better technologies for energy production and energy conservation. We also need better agricultural technologies that would allow us to more rapidly change crop mixes to fit with climate changes and to develop crop strains that are more resistant to whatever weather might throw at them. If climate changes become big enough at some point we'll even need climate modification technologies.
Benny Peiser, a social anthropologist at Liverpool John Moores University in England, argues that global warming may bring more benefits than costs.
A large number of studies show that urban populations in the USA and Europe have successfully adapted to recurrent extreme weather events and heatwaves. People who used to be much more weather-sensitive only 30 or 40 years ago have become less susceptible to extreme climate conditions and heatwaves due to improved medical care, increased access to air conditioning, and biophysical and societal adaptations (4).
These studies essentially falsify the contention that future warming will lead to a significant increase of heat-related mortality rates. In fact, some of Britain's leading medical experts have calculated that a rise of the average temperature by two degrees Celsius over the next 50 years would increase heat-related deaths in Britain by about 2,000 - but would reduce cold-related deaths by about 20,000 (5). In other words, the decrease in the number of cold-related deaths would be much more significant (by a factor of 10) than the heat-related deaths due to rising temperatures. The potentially huge health benefits of moderate temperature increases have been confirmed by other researchers. They estimate that a warming of 2.5 degree Celsius would lower the annual death rate by 40,000 in the USA alone while reducing medical cost by almost $20 billion per year (6).
Very cold temperatures stress old tired hearts just as very hot temperatures do. If that is the biggest reason for the expected lowered annual death rates then my guess is that the dip in death rates would be temporary as a bunch of old folks got their day of reckoning shifted out by a couple of years. Eventually their aged and weak hearts are going to kill them anyway.
As for people becoming less susceptible to the weather: Yes, this is definitely the case in industrialized countries. This trend has gone so far as to help catalyze a massive shift in the American population southward (and a similar trend is discernible in Europe though on a smaller scale). People can better handle the hot summers of the Carolinas, Georgia, Florida, Alabama, Mississippi, Louisiana, and Texas because they have air conditioning. Growing numbers of people live in Palm Springs California all year around (as compared to the previous practice of only wintering there) again because of affordable air conditioning. It is worth noting that the decline in climate-related deaths in America has happened in parallel with the shift of populations into areas with more extreme weather conditions.
The thrust of Peiser's argument is that global warming gloomsters tend to tally up only the costs of warming and not any of the benefits. I think he is right about that. Parts of the world that are extremely cold in winters will become more livable as the world warms. Finland, for example, might derive a big net benefit from global warming. Russians in Siberia might find it an improvement as well. Also, while weather patterns and, in particular, rainfall patterns will shift it is not clear to me that this will lead to a net decrease in agricultural production. Certainly growing seasons will get longer.
Though I think Peiser goes too far in his argument here:
Given the accelerated economic growth and technological progress in the developing world, successful adaptation to increasing or decreasing temperatures will become a universal feature in the not too distant future.
The bulk of population increase in the next 50 years will take place in what some call "developing countries". The problem is that a great many of those countries are not developing. Africa in particular comes to mind as the basket case of the world. Africa is glaringly failing to develop economically. Hotter temperatures are not going to be ameliorated in Africa with air conditioning. Also, India's rate of economic development is lagging China's and Burma/Myanmar is not a poster child for economic development (though that might change as China's influence there gradually turns the place into a virtual colony of China).
But suppose improbably that all the less developed countries could miraculously follow China's pattern of economic development and a few billion more people could afford to buy air conditioners. Such a massive increase in buying power would cause an enormous increase in fossil fuel burning and an atmospheric carbon dioxide (CO2) rise that would be greater than the current pessimistic climate forecasts. If we could even find the fossil fuels to burn we'd face an environmental disaster. Air conditioning the whole world with fossil fuels does not strike me as a realistic option.
If fossil fuel use is restricted by regulatory regimes aimed at reducing CO2 then the higher costs of air conditioning in the summer and heating in the winter will reduce the use of heaters and air conditioners and lead to more weather-related deaths in industrialized countries. But while those deaths will rise other deaths from heat will likely be avoided less developed countries which are mostly closer to the equator than the industrialized countries.
What we need are technologies that provide cheaper and less polluting energy. If we had those technologies we would not need to spend so much time arguing about green house gasses and climate projections. Rather than saddle the industrialized economies with very high taxes on fossil fuels to reduce energy use with a resulting slowing of economic growth why not launch a Manhattan Project to develop new energy sources?
By the year 2050, the current world population of 6.5 billion is expected to increase to a possible 10 billion. According to Smalley, the energy required to maintain this population will theoretically more than double from the 14 Terawatts used per day in 2003 to 30-60 Terawatts in 2050.
In his argument, Smalley showed that 165,000 TW of energy from the sun hits the earth's surface every day. "We only need 20 to completely sum up the world's energy needs," Smalley said.
Solar satellites anyone?
Because right now, we have 6-and-a-half billion people on the planet of which about only 1 billion are really consuming energy at a significant rate. Those other 5-and-a-half billion people are going to, there's no way to stop it. We don't want to stop it, consume energy. By the middle of the century, at least a factor of two more energy will be produced every day. Right now it's about 200 million barrels of oil every day are burnt up one way or another. Either as oil or as gas or as coal or other energy sources.
By mid-century we're going to need at least 400. Where's that going to come from? Well if it has to come from oil, and the way that we're used to getting it, the low cost we're usually getting it, it's not by any means certain there will be that oil there. In fact, we may peak within the next couple of years or the next 10 years. By mid-century we will have peaked, so where are the billions of people on the planet going to have their primary energy coming from? Where?
Note that China is going to add another billion to the set of people who use energy at a significant rate.
Smalley believes that nuclear fission power is the only realistic energy alternative to fossil fuels but only in very stable societies that can safeguard it properly. (note that this is from 1996 and so his "next century" is the 21st century)
Right now, I believe there really is only one alternative that could really apply to the energy needs of the entire planet. That alternative is nuclear—nuclear fission in particular, not nuclear fusion.
"I believe that the United States, Europe, and Japan are stable enough societies that they could generate all their power by nuclear fission and provide the necessary stewardship to make the planet safe...
"It would be very nice to have an alternative to fossil fuels—an alternative to nuclear fission—that would be capable of providing energy for what will probably be 10-15 billion people in the middle of this next century. I believe that if this alternative exists, it has to be solar. Right now we do not even have a solar technology that is even laughably close to being able to handle—for example—80% of all the world's energy production. If you don't do 80%, you're not touching the problem. And if you don't provide energy technology that is economically cheaper than the alternatives, it won't be adopted at all.
"Where is that solar technology going to come from? [It will come] not just from improving solar cells, but from something totally new. On a cloudy day in New York, can take most of the photons that hit on cheap collectors and store it in some useful form of energy—like hydrogen or electric charge. When you think about the physics that controls that, you're rapidly led to the conclusion that the physics which makes this possible happen within a little, 1 nm cubic box....
"I don't know what that solar technology is going to be, but I'll bet you that it's nanotechnology."
One really big advantage that would come from solar cells built using nanotechnology is that they would be safe enough for the whole world to use. We ought to be developing better nuclear reactors (e.g. pebble bed modular reactors) for the developed countries and doing nanotechnology research into photovoltaic cells to make photovoltaics orders of magnitude cheaper.
We need to start working seriously on alternatives to fossil fuels.
A pair of Canadian researchers, University of Guelph Canada economist Ross McKitrick and Toronto-based mineral exploration consultant Stephen McIntyre, have a paper coming out in Geophysical Research Letters that challenges the "Hockey Stick" temperature trends model which shows the 20th century as the hottest centure in the last 1000 years.
Until now, criticisms of the hockey stick have been dismissed as fringe reports from marginal global warming skeptics. Today, however, the critical work of two Canadian researchers, Ross McKitrick, an economics professor at Guelph University, and Toronto consultant Stephen McIntyre, will be published by Geophysical Research Letters, the prestigious journal that published one of the early versions of Michael Mann's 1,000-year tracking of Northern Hemisphere temperatures,
Publication in Geophysical Research sets McIntyre and McKitrick's analysis and conclusions in direct opposition to the Mann research. Their criticism can no longer be dismissed as if it were untested research posted on obscure Web sites by crank outsiders. Their work is now a full challenge to the dominant theme of the entire climate and global warming movement.
The paper will be published in February. So as of this writing it is not on the Geophysical Research Letters web site. However, a pre-publication version of the paper "“Hockey Sticks, Principal Components and Spurious Significance”" is available (PDF format).
For a graphical comparison of the original hockey stick chart and the McIntyre and McKitrick analysis see this page from McKitrick's web site. That page has a lot of other useful links. McIntyre and McKitrick also have another web site with a lot more useful links.
Dutch science journalist Marcel Crok has a two part series in the Canadian Financial Post on the McIntyre and McKitrick research paper.
Up to January, 2005, none of McIntyre and McKitrick's findings had been published by major scientific journals. Thus, in the opinion of established climate researchers, there was no reason to take them seriously. Climate researchers were quite comfortable in their consensus and repeatedly referred to this "consensus" as a basis for policy. The official expression of the consensus comes from the IPCC. This group, under the flag of the United Nations, comes out with a bulky report every five years on the state of affairs in climate research. Hundreds of climate researchers from every corner of the world contribute to it. In the third report in 2001, Mann himself was a lead author of the chapter on climate reconstructions.
McKitrick and McIntyre had a hard time getting access to the data and source used in the analysis by Mann and colleagues that led to their claim that the 20th century was the hottest in the last 1000 years. No other group had seriously tried to replicate the Mann analysis.
McIntyre sent an e-mail to Michael Mann in spring 2003, asking him for the location of the data used in his study. "Mann replied that he had forgotten the location," he said. "However, he said that he would ask his colleague Scott Rutherford to locate the data. Rutherford then said that the information did not exist in any one location, but that he would assemble it for me. I thought this was bizarre. This study had been featured in the main IPCC policy document. I assumed that they would have some type of due-diligence package for the IPCC on hand, as you would have in a major business transaction. If there was no such package, perhaps there had never been any due diligence on the data, as I understood the term. In the end, this turned out to be the case. The IPCC had never bothered to verify Mann, Bradley and Hughes' study."
Despite billions of dollars spent on climate research, academic and institutional researchers had never bothered to replicate Mann's work either. In 2003, McIntyre tackled the job and, from an unusual hobby, the task has since grown to become almost a full-time occupation. On an Internet forum for climate skeptics, he met Ross McKitrick, professor of economics at the University of Guelph, just outside of Toronto. Since meeting in person in September of 2003, the two have been working on the project together. McIntyre does most of the research and McKitrick asks questions and assists in the writing of papers.
When people tell us that we urgently need to spend hundreds of billions or trillions to fix some problem we ought to demand a higher standard of proof than the effort that went into the original Hockey Stick paper.
Read the full article. Keep in mind as you read it that published science should be transparent, verifiable, and reproducible. Science that can not be checked and reproduced has no place as a basis for public policy that could cost the world's collective economies hundreds of billions or even trillions of dollars..
"More strangely," said McIntyre, "the series appears twice in Mann's data set, as an individual proxy, and in the North American network. But it is only extrapolated in the first case, where its influence is very strong." McIntyre and McKitrick went back to the source of the Gaspe series and then to the archived data at the World Data Center for Paleoclimatology."We found that although the Gaspe series begins in 1404, up until 1421, it is based on only one tree. Dendrochronologists (tree ring researchers) generally do not use data based on one or two trees. The original authors only used this series from 1600 onwards in their own temperature reconstructions. This series should never have been used in the 15th century, let alone counted twice and extrapolated."
Go and read the full articles I'm linking to. Note how McIntyre and McKitrick were able to find a Fortran program and crucial datasets on an FTP server used by Mann's group that led McIntyre and McKitrick to an understanding of how Mann and his colleagues made serious mistakes in how they did a mathematical analysis called principal component analysis (PCA) on their datasets. There is a larger lesson here: More data and source code on which scientific research papers are based ought to be available in the public domain to allow replication of mathematical analyses used in scientific research papers.
Note also that in climate research McIntyre and McKitrick are essentially self-taught amateurs. But they had the mathematical chops to use basic analytical techniques to datasets and apparently that is all that is needed do analyses on climate history data.
"Do you believe in global warming? That is a religious question. So is the second part: Are you a skeptic or a believer?" said Massachusetts Institute of Technology professor Richard Lindzen, in a speech to about 100 people at the National Press Club in Washington, D.C.
"Essentially if whatever you are told is alleged to be supported by 'all scientists,' you don't have to understand [the issue] anymore. You simply go back to treating it as a matter of religious belief," Lindzen said. His speech was titled, "Climate Alarmism: The Misuse of 'Science'" and was sponsored by the free market George C. Marshall Institute. Lindzen is a professor at MIT's Department of Earth, Atmospheric, and Planetary Sciences.
According to Lindzen, climate "alarmists" have been trying to push the idea that there is scientific consensus on dire climate change.
"With respect to science, the assumption behind the [alarmist] consensus is science is the source of authority and that authority increases with the number of scientists [who agree.] But science is not primarily a source of authority. It is a particularly effective approach of inquiry and analysis. Skepticism is essential to science -- consensus is foreign," Lindzen said.
Alarmist predictions of more hurricanes, the catastrophic rise in sea levels, the melting of the global poles and even the plunge into another ice age are not scientifically supported, Lindzen said.
"It leads to a situation where advocates want us to be afraid, when there is no basis for alarm. In response to the fear, they want us to do what they want," Lindzen said.
If global warming eventually becomes a problem we will be able to handle it. We can switch to nuclear power. In time photovoltaic cells will become much cheaper and we may switch away from fossil fuels in 30 years because market forces cause the switch even without government regulations that force the switch. The most prudent action to take at this point would be to accelerate the rate of energy research to develop cheaper alternatives to fossil fuels and cheaper ways to capture and sequester CO2. The impositions of huge costs on economies to reduce CO2 emissions today is an excessive response to a potential problem that, if it comes, could be much more cheaply handled in the future.
Update: Check out the Prometheus blog on science policy and the post A Third Way on Climate?. For insights into the problems caused by scientists playing policy advocates while simultaneously trying to serve the role of providing authoritative answers about scientific knowledge to the public see these posts Chris Landsea Leaves IPCC, Follow Up On Landsea/IPCC, Landsea on Hurricanes, More Politics and IPCC, and A Good Example why Politics/IPCC Matters. There is a lot of sensible thinking in those posts. Hope you agree.
By eating phytoplankton sardines may prevent the process where when phytoplankton die they settle on the bottom of the ocean and then get broken down (presumably by bacteria) to release methane. Over-fishing sardines may increase methane release into the atmosphere.
Milky, turquoise-colored “dead zones,” sometimes as large as New Jersey, of rotting fish and caustic stench floating off the coast of southwest Africa, may be a sign of things to come for other areas along the coastlines of the eastern Atlantic and Pacific oceans. Toxic gas eruptions—bubbling up from the ocean floor to kill sea life, annoy human seaside residents, and may even intensify global warming—cause the dead zones. But the humble sardine may help to save the day, according to a study from the Pew Institute for Ocean Science.
In an article published in the November issue of Ecology Letters, authors Andrew Bakun and Scarla Weeks compare several areas around the world where strong offshore winds cause an upwelling of nutrients in the ocean and thus a population explosion of phytoplankton, the microscopic plant life that drifts through the ocean. Studying the waters off the coast of Namibia, the scientists report how the resulting overproduction of phytoplankton dies and sinks to the bottom, and how the decaying organic matter releases copious amounts of methane and poisonous “rotten egg” smelling hydrogen sulfide gas.
As methane is 21 times more effective than carbon dioxide at trapping heat in the atmosphere, the resulting climate change may intensify this upwelling process and open the possibility of even larger and more plentiful eruptions.
One action to help keep this situation from worsening, the authors say, is to avoid the overfishing of sardines, which can devour large quantities of phytoplankton.
“The region in question formerly hosted a large population of sardines that have been overfished,” says Bakun, a member of the Pew Institute and professor of marine biology and fisheries at the University of Miami Rosenstiel School of Marine and Atmospheric Science. “It is at least encouraging that a minor resurgence of sardine abundance coincided with a noticeable temporary hiatus in eruption frequency off Namibia in 2002.”
Bakun and Weeks, from the University of Cape Town in South Africa, also warn that areas near Cape Mendocino, California, and Cape Sim, Morocco, may be dangerously close to the “tipping point,” possibly ripe for phytoplankton population explosions followed by their gaseous demise.
“This study demonstrates that overfishing one species of fish, such as sardines, can profoundly alter an entire marine ecosystem in ways that may be difficult or impossible to reverse,” says Ellen Pikitch, executive director of the Pew Institute for Ocean Sciences and an expert on fishery science and management.
Pew’s Chief Scientist Elizabeth Babcock adds, “The California sardine population has recovered somewhat since it peaked in the 1940s and was depleted by the early 1960s. We hope that the population can continue to recover as a hedge against development of such a regrettable situation on our own coast.”
Healthy sardine populations for a healthier atmosphere. Who would have thought?
For at least the last 5 years James Hansen of NASA has been arguing that reduction in methane gas emissions is a cheap way to delay global warming while providing more immediate health benefits (see the middle and end parts of that post).
Is low-lying coastal property a bad investment? Will the polar bears be driven to extinction by the total melting of the Arctic Ice Cap? Will the climate of Alaska and Canada become more congenial for those who prefer warmer weather? Should we panic? Is disaster looming? Why these grand questions? It is time for yet another prestigious and apocalyptic climate trends research report.
The newly released Arctic Climate Impact Assessment report predicts major Arctic snow and ice melting over the next 100 years.
WASHINGTON—The Arctic is warming much more rapidly than previously known, at nearly twice the rate of the rest of the globe, and increasing greenhouse gases from human activities are projected to make it warmer still, according to an unprecedented four-year scientific study of the region conducted by an international team of 300 scientists.
At least half of the summer sea ice in the Arctic is projected to melt by the end of this century, along with a significant portion of the Greenland Ice Sheet, as the region is projected to warm an additional 7 to 13°F (4-7°C) by 2100. These changes will have major global impacts, such as contributing to global sea-level rise and intensifying global warming, according to the final report of the Arctic Climate Impact Assessment (ACIA).
The assessment was commissioned by the Arctic Council (a ministerial intergovernmental forum comprised of eight nations, including the United States, and six Indigenous Peoples organizations) and the International Arctic Science Committee (an international scientific organization appointed by 18 national academies of science).
• In Alaska, Western Canada, and Eastern Russia average winter temperatures have increased as much as 4 to 7°F (3-4°C) in the past 50 years, and are projected to rise 7-13°F (4-7°C) over the next 100 years.
• Arctic sea ice during the summer is projected to decline by at least 50 percent by the end of this century with some models showing near-complete disappearance of summer sea ice. This is very likely to have devastating consequences for some arctic animal species such as ice-living seals and for local people for whom these animals are a primary food source. At the same time, reduced sea ice extent is likely to increase marine access to some of the region’s resources.
• Warming over Greenland will lead to substantial melting of the Greenland Ice Sheet, contributing to global sea-level rise at increasing rates. Over the long term, Greenland contains enough melt water to eventually raise sea level by about 23 feet (about 7 meters).
• In the United States, low-lying coastal states like Florida and Louisiana are particularly susceptible to rising sea levels.
• Should the Arctic Ocean become ice-free in summer, it is likely that polar bears and some seal species would be driven toward extinction.
I'm not particularly worried about the flooding of Florida retirement communities. The retirees can all move onto cruise ships. The Love Boat TV show could be resurrected with spin-offs that are hybrids with Law And Order TV shows set on different ships. Instead CSI: Miami and CSI: Las Vegas there could be CSI: Norwegian Valkyrie and CSI: Princess Casino.
One aspect on which researchers are keeping their eye: the release of methane and carbon dioxide as permafrost thaws and tundra decomposes. Even if the advance of forests to higher latitudes soaks up some of this released CO2, this still leaves methane - a much more potent greenhouse gas - free to enter the atmosphere.
Ron Bailey, science writer for the libertarian Reason magazine says not so fast. Ron points to lots of contrary facts that argue for a less apocalyptic view of future climate history.
But University of Alabama at Huntsville climatologist John Christy, a climate expert on whom I have relied for years, makes some interesting observations about the Arctic Council's report. "If you look at the long term records, the Arctic has been as warm or warmer than it is today," says Christy. He cites temperature data from the Hadley Centre in the UK showing that from 70 degrees north latitude to the pole, the warmest years on record in the Arctic were 1937 and 1938. This area is just slightly above the Arctic Circle.
Furthermore, those same records show that the Arctic warmed twice as fast between 1917 and 1937 as it has in the past 20 years. After 1940, the Arctic saw a big cool-down and climatologists noted sea ice expanding in the northern Atlantic. Christy argues that what he calls the Great Climate Shift occurred in the late 1970s and caused another sudden warming in the Arctic. Since the late 1970s there has not been much additional warming in the region at all. In fact, on page 23, the Arctic Council Assessment offers very similar data for Arctic temperature trends from 60 degrees north latitude—the area that includes most of Alaska and essentially all of Greenland, most of Norway and Sweden, and the bulk of Russia.
Ron's article has lots more fun facts about what is going on with the climate. Check it out.
So should we be alarmed? Should we wait for the science to become more certain? What is the prudent position to take? Keep in mind that even if the more apocalyptic projections are closer to the truth any choice that uses resources to reduce CO2 emissions with current technology or technology that will be available in the short-to-medium term ends up incurring opportunity costs. Money spent to comply with a massive international regulatory scheme to reduce CO2 emissions would be money not spent on other activities that would cause economic growth. Economic growth gives us more wealth with which to solve problems more easily in the future.
An argument can be made that we should wait a couple of decades to respond to the green house gas build up in order to wait for a scientific understanding of the problem and also because better cheaper technologies for reducing carbon dioxide (CO2) emissions will be available then. Money spent to use today's technologies will buy us less emissions reduction than money spent 20 or 30 years from now using the technologies available then. Also, slower economic growth would condemn large chunks of the populaitons of less developed countries to prolonged poverty. Given that most of the projected damage from green house warming comes in the last part of the 21st century waiting two or three decades does not cause that much harm (assuming of course that it even causes any harm at all).
However, there is yet another argument worth considering from climate scientist James Hansen of NASA. Hansen has put forward the rather persuasive argument that reduction in non-CO2 green house emission such as soot and methane would provide immediate human health benefits while simultaenously providing a greater cooling effect than the same number of dollars spent on reduction of CO2 emissions would provide. Hansen does not argue against reducing CO2 emssions (see Hansen's clarification of his position on CO2 emissions for more details). However, his basic insights are that not all emissions are equally costly to reduce and that some emissions reductions provide guaranteed improvement in ground air quality and hence benefits for human health. So why not go for reducing those types of emissions first? Makes sense to me.
There is another argument that I hear less often though my regular readers hear it often enough from me: Why not spend more money on research to develop less polluting technologies rather than spend far larger sums on a massive international CO2 emissions enforcement regime for the Kyoto Accords? Kyoto and other proposed regimes for CO2 emissions reduction have cost estimates that range from the tens of trillions of dollars to the hundreds of trillions of dollars . I mean, we are talking about mind-booglingly huge sums of money.
Isn't there an easier and less painful way to deal with a potential problem whose exact costs and benefits may not even be as bleak as the doom-sayers claim? Is it that international bureaucrats and left-liberal lovers of regulations like to make people suffer? Do they think that living in a modern industrial economy amounts to a form of original sin that has to be punished in order to save our ecological souls from damnation by the world Gaia spirit?
Well, instead of a regulatory regime with costs that range into the hundreds of trillions of dollars imagine research efforts that are aimed at developing energy technologies that are simultaneously cheaper and cleaner. Then market mechanisms would do the work of displacing polluting technologies with cleaner technologies.
A research approach would cost a few orders of magnitude less than the regulatory approach. A few orders of magnitude lower cost approach would translate into rather hefty numbers of dollars with a range of tens of billions or hundreds of billions of dollars. That would be plenty of money to fund a lot of research into photovoltaic materials, lighter weight lithium polymer batteries, fuel cells, superconducting materials, nuclear pebble bed modular reactors, and other energy technologies that hold out the possibility of energy sources that are cleaner and cheaper.
Update:Over at Marginal Revolution Fabio Rojas sums up a Daniel Ben-Ami essay about environmentalists and points out that a lot of environmentalists favor solutions to environmental problems that mandate a reduction in production.
He notes that since the Enlightenment people have thought that human progress comes from mastery over nature and from being more productive, but many environmentalists think that human well being is harmed by being more productive. It's an important point that leads to some real policy differences. If you think that we have too many green house gases, then you have two choices: stop manufacturing or learn to manufacture without as much pollution. Too many environmentalists opt for the first choice, which is bad because so much of the world's poor look to gain from industry.
Since so many environmentalists think this way they tend to have an outsized influence on framing how environmental issues get debated. The range of policy options that get debated too often tends to be short on more innovative solutions that avoid the need for decreases in economic products.
Is the influence of Enlightenment thinking on the decline? It seems to me that the Enlightenment view of nature is similar to the Christian view in that humans are held as being above nature and hence have a right to master it use it. Are we moving toward a more pagan age with a reduced embrace of both the Enlightenment view and the Christian views of nature?
Also see Daniel Ben-Ami's essay.
The discussion of global warming provides a striking example of how this works. Almost everyone accepts that climate change means that the world needs to cut back on emissions of greenhouse gases. Yet this would almost certainly mean holding back economic growth, meaning that a large part of the global population will remain poor. There is hardly any discussion of how to deal with global warming while generating substantial economic growth at the same time. Indeed it will be argued that economic growth, far from being the problem, is central to humanity's capacity to handle climate change.
There are two recurring themes running through the environmentalist approach to economics. First, an obsession with the need for limits. The environmentalist debate, in numerous different ways, assumes that strict limits must be put on economic activity. Such premises ignore or at least downplay the power of human creativity. Economic activity does indeed often throw up problems - such as pollution - but it also, it will be argued, provides the means to overcome them.
A particular hate figure for environmentalists is Francis Bacon (1561-1626), the earliest advocate of the notion that man should attempt to take control over nature. For Vandana Shiva, one of India's leading environmentalists, his views are akin to rape and torture. She argues that: 'His was not a "neutral", "objective", "scientific" method. Rather it was a peculiarly masculine mode of aggression and domination over women and non-Western cultures. The severe testing of hypotheses through controlled manipulations of nature, and the necessity of such manipulations if experiments are to be repeatable, were formulated by Bacon in clearly sexist metaphors. Both nature and the process of scientific enquiry appear conceptualized in ways modelled on rape and torture - on man's most violent and misogynous relationship with women.' (35)
Shiva isn't on the fringes of environmentalist thinking - in 2000 she gave a prestigious BBC Reith lecture as part of a series on 'respect for the earth' (36). Neither is she alone in castigating Bacon in such extreme terms. For instance, a collection edited by Herman Daly includes a 1947 essay in which the author CS Lewis compares Bacon to Marlowe's Faustus - selling his soul to the devil (37).
For environmentalists, there is no difference between control over nature and the destruction of the Earth. Mastery of nature is, in this view, synonymous with its obliteration. But for the supporters of the Enlightenment there is a fundamental difference between conquest and destruction. Human mastery of nature means controlling disease, averting natural disasters and above all overcoming scarcity. Conquest of nature is fundamental to human progress, and at the centre of the development of civilisation.
I'm all for mastering nature. Lets build giant reflectors in orbit in the year 2030 or 2040 (using a nanotech bean pole to bring up the construction materials into orbit) and reflect light toward or away from Earth as needed.
The Earth Institute at Columbia University, NYC--Researchers suggest that reductions of trace gases may allow stabilization of climate so that additional global warming would be less than 1° C, a level needed to maintain global coastlines. Although carbon dioxide emissions, an inherent product of fossil fuel use, must also be slowed, the required carbon dioxide reduction is much more feasible if trace gases decrease.
In the current edition of Proceedings of the National Academy of Sciences, Drs. James Hansen and Makiko Sato of NASA's Goddard Institute for Space Studies (GISS) at the Earth Institute at Columbia University suggest that avoidance of large climate change requires the global community to consider aggressive reductions in the emissions of both carbon dioxide and non-carbon dioxide gases called trace gases. Humans have already increased the amount of carbon dioxide in the air from 280 parts per million (ppm) to 380 ppm. If the world continues on its current trajectory of increasing carbon dioxide, methane and ozone, the likely result will be large climate change, with sea level rise of a few meters or more.
Hansen and Sato point out that if methane and other trace gases are reduced, climate could be stabilized, with warming less than 1°C, at carbon dioxide levels of 520 ppm. However, if the trace gases continue to increase, carbon dioxide would have to be kept beneath 440 ppm. A cap of 440 ppm seems practically impossible to stay under due to existing energy infrastructure. However, Hansen and Sato suggest that, with the possibility of new technologies by mid-century, it is feasible to keep carbon dioxide levels from exceeding approximately 520 ppm.
The co-authors suggest that the non-CO2 gases could be addressed via a Montreal Protocol-like process, or by adding additional gases to the Montreal Protocol itself. The Montreal Protocol has been very effective in reducing emissions of gases that destroy stratospheric ozone. Developed and developing countries have worked together harmoniously in this process, with the World Bank providing support for participation of developing countries.
Cutting back on methane emissions would be pretty cheap to do and would provide health benefits for reasons unrelated to global warming.
The activity of the Sun over the last 11,400 years, i.e., back to the end of the last ice age on Earth, has now for the first time been reconstructed quantitatively by an international group of researchers led by Sami K. Solanki from the Max Planck Institute for Solar System Research (Katlenburg-Lindau, Germany). The scientists have analyzed the radioactive isotopes in trees that lived thousands of years ago. As the scientists from Germany, Finland, and Switzerland report in the current issue of the science journal "Nature" from October 28, one needs to go back over 8,000 years in order to find a time when the Sun was, on average, as active as in the last 60 years. Based on a statistical study of earlier periods of increased solar activity, the researchers predict that the current level of high solar activity will probably continue only for a few more decades.
The research team had already in 2003 found evidence that the Sun is more active now than in the previous 1000 years. A new data set has allowed them to extend the length of the studied period of time to 11,400 years, so that the whole length of time since the last ice age could be covered. This study showed that the current episode of high solar activity since about the year 1940 is unique within the last 8000 years. This means that the Sun has produced more sunspots, but also more flares and eruptions, which eject huge gas clouds into space, than in the past. The origin and energy source of all these phenomena is the Sun's magnetic field.
Since increased sunspot activity is correlated with higher solar energy output it is possible that Earth climate temperatures in recent decades have been higher due to increased solar radiation hitting the Earth.
Because the brightness of the Sun varies slightly with solar activity, the new reconstruction indicates also that the Sun shines somewhat brighter today than in the 8,000 years before. Whether this effect could have provided a significant contribution to the global warming of the Earth during the last century is an open question. The researchers around Sami K. Solanki stress the fact that solar activity has remained on a roughly constant (high) level since about 1980 - apart from the variations due to the 11-year cycle - while the global temperature has experienced a strong further increase during that time. On the other hand, the rather similar trends of solar activity and terrestrial temperature during the last centuries (with the notable exception of the last 20 years) indicates that the relation between the Sun and climate remains a challenge for further research.
We are in an unusually long period of increased Solar activity. So an eventual decline seems highly likely. What we do not know is what will happen to Earth's climate when the Sun's output finally does decline. Depending on how far it declines cooling could become a bigger risk than warming. But we can't predict whether that will be the case. But human technology will advance so far in the next few decades that large scale climate engineering to cancel out either a warming or a cooling will become feasible. So either way I do not think we need to be deeply concerned in the short run.
This latest report builds on a previous research paper produced by Sami K. Solanki and colleagues several months ago which took a look at sunspot activity going back only 1000 years. See my previous post Sun Energy Output At Over 1,000 Year Peak for more information. Also see
Well, as Gilda Radner playing Roseann Roseannadanna used to say "its always something". The Christian Science Monitor has an article on the dangers posed to marine organisms by rising levels of carbonic acid formed by carbon dioxide dissolving into the oceans.
By the middle of the next century, for example, coral reefs in shallow waters could lose up to 30 percent of the calcium carbonate they need to build their structures, calculates an international research group led by Joan Kleypas, a marine biologist at the National Center for Atmospheric Research in Boulder, Colo. That could lead to stunted growth or other effects, which could make them more vulnerable to erosion or storm damage.
Also, increased CO2 levels caused key plankton species to create badly formed or incomplete calcium carbonate shells, according to a team led by Ulf Riebesell with the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, Germany. In lab experiments the ratio of shell to the rest of the organism dropped by as much as 52 percent.
Here is yet another report claiming yet another harm caused by carbon dioxide emissions produced by burning fossil fuels. What to do about it? Suppose atmospheric carbon dioxide build-up is going to cause even a quarter as many problems as the alarmists claim then isn't the most sensible and cost-effective response to spend money on basic research into energy technologies that will reduce or stop the emissions of carbon dioxide or even remove it from the atmosphere? Cheaper and cleaner energy technologies would displace fossil fuels without any regulatory interventions. No international treaties or international disputes about emissions would be needed.
There are historical parallels for cheaper cleaner technologies displacing more expensive and dirtier technologies. The displacement of coal for heating by oil and natural gas was driven by cost and convenience. No one wanted to wake up and shovel coal into their house heater in the morning or to clean out the accumulated ash or pay for chimney sweeps.
A regulatory response to the problem of carbon dioxide emissions would be incredibly expensive with total costs running into the hundreds of trillions of dollars. Contrast with this an alternative approach: spend major research bucks (Nobelist Richard Smalley argues for $10 billion a year which is a huge sum for basic research) to develop energy technologies that will be cheaper than fossil fuels and far less polluting.
Over on the Crumb Trail blog back40 argues that Richard Smalley may be advocating premature choosing of potential technological winners in energy technologies. However, I do not see Smalley's approach to energy funding through grants to basic researchers as likely to suffer from that problem. Obviously large major categories of research have to be chosen. But that is the case with, for example, NSF and NIH funding where the agencies have many subcategories of research in which researchers can apply for grants. It is easy to imagine, say, a category for photovoltaic thin films and another for photovoltaic nanotubes. Similarly, one can imagine a few subcategories for batteries and fuel cells. At a $10 billion a year funding level broken out across many categories it seems unlikely any major area of promising research would be neglected.
Even if the scale of the carbon dioxide accumulation problem is exaggerated that is not an argument against obsolescing fossil fuels. The displacement of fossil fuels through new energy technologies would provide a number of other benefits including lowering costs of energy, a reduction of a variety of pollutants that really do cause harm (e.g. particulates, mercury, sulfur oxides, and ground level ozone), and a reduction in the flow of money into Middle Eastern countries where it funds terrorism and the spread of Wahabbi and Salafist Islam. A regulatory approach to carbon dioxide emissions reduction would provide much less of each of these other benefits.
Some climate scientists are arguing that the intensity of cosmic rays from distant exploding stars varies over time to cause long term changes in Earth's climate.
The idea will also be backed up by Nigel Marsh of the Danish Space Research Institute in Copenhagen.
Marsh and his colleagues looked at satellite images of low-altitude clouds from the past 20 years. They noticed that the pattern of global cloud cover varied over a time scale of roughly 10 years, and found a correlation with the 11-year sunspot cycle.
The more sunspot activity there is, the greater the strength of the sun's magnetic field. And cosmic rays are deflected by this field, so the stronger it is, the fewer rays reach the Earth, and the lower the cloud cover.
The Copenhagen team also found that clouds were scarce near the equator and thicker towards the tropics. According to Marsh, this is because cosmic rays have a hard time punching through Earth's magnetic field at the equator, but can leak in through the relatively weaker field nearer the poles.
The Sun is known to go through periods of much lower sunspot activity. One such period is known as the Maunder Minimum coincided with the "Little Ice Age" back in 1645-1715. During low sunspot periods it is thought that the Sun puts out less light energy and hence causes a cooling effect on Earth's climate. But this theory about cosmic rays basically provides another way that sunspot activity fluctuations can cause climate fluctuations: low sunspot activity reduces the magnetic field of the sun and therefore lets more cosmic rays through to the Earth to increase cloud cover and therefore to cause reflection of light before it reaches the surface.
One of the proponents of this theory, Nir Shaviv of the Hebrew University in Jerusalem, Israel has an interesting set of web pages arguing his view point. See his graph of Earth climate cycles and Milky Way galaxy spiral arm rotations.
There are indications that Cosmic Rays affect climate on Earth. If this is true, then one should expect climatic variations while we roam the galaxy. This is because the density of cosmic ray sources in the galaxy is not uniform. In fact, it is concentrated in the galactic spiral arms (it arises from supernovae, which in our galaxy arise predominantly from the death of massive stars, which in turn form and die predominantly in spiral arms). Thus, each time we cross a galactic arm, we should expect a colder climate. Current data for the spiral arm passages gives a crossing once every 135+/-25 Million years.
A record of the long term variations of the galactic cosmic ray flux can be extracted from Iron meteorites. It was found in this work that the cosmic ray flux varied periodically (with flux variations greater than a factor of 2.5) with an average period of 143 +/- 10 Million years. This is consistent with the expected spiral arm crossing period and with the picture that the cosmic ray flux should be variable. The agreement is also with the correct phase.
The main result of this research, is that the variations of the flux, as predicted from the galactic model and as observed from the Iron meteorites is in sync with the occurrence of ice-age epochs on Earth. The agreement is both in period and in phase: (1) The observed period of the occurrence of ice-age epochs on Earth is 145+/-10 Myr (compared with 143 +/- 10 Myrs for the Cosmic ray flux variations), (2) The mid point of the ice-age epochs is predicted to lag by 31 +/- 8 Myr and observed to lag by 33 +/- 20 Myr. This can be seen in the following graph:
I am in no way qualified to comment on the plausibility of this particular theory. But there have been a number of surprising discoveries in recent years of unexpected factors that influence climate (see my Trends Climate category archives for interesting examples). This leads me to suspect that current climate models are too simple to use with a high level of confidence when making public policy decisions. There is a large degree of uncertainty when we look ahead at the future of Earth's climate.
A team of Duke University researchers led by Jim Clark looking at core drillings found repeated dust bowl periods during "the mid-Holocene period of 5,000 to 8,000 years ago in parts of the Dakotas, Montana and western Minnesota".
PORTLAND, ORE. – Events like the great Dust Bowl of the 1930s, immortalized in "The Grapes of Wrath" and remembered as a transforming event for millions of Americans, were regular parts of much-earlier cycles of droughts followed by recoveries in the region, according to new studies by a multi-institutional research team led by Duke University.
Some of those prehistoric droughts in the northern Great Plains of what is now the United States also lasted longer than modern-day dry spells such as the 1930's Dust Bowl decade, according to sediment core studies by the team.
The group's evidence implies these ancient droughts persisted for up to several decades each. At their heights, prairie fires became uncommon because there was too little vegetation left to burn. The ages of charcoal deposits suggest instead that prairie fires occurred during intervening wet periods, with each wet-dry cycle lasting more than a century each.
Too many people believe that whatever weather one has seen in one's own lifetime is "normal". When weather suddenly veers from the pattern one has become accustomed to there is a human tendency to look for some exceptional cause such as human intervention. While human intervention may well be changing the climate the climate is not stable to begin with. We should expect large climate changes as natural.
Even the 1930s drought was not unique in modern times with the 1890s having gone through a drought period as well. But there was no John Steinbeck around to write a great novel about the 1890s drought let alone a silver screen adaptation of the story.
The regularity of these ancient droughts make much more recent Great Plains droughts in the 1890s and 1930s appear "unremarkable" by comparison, Clark said, even though the contemporary ones "walloped people."
The study did not speculate how the findings might relate to anticipated future climate change, when a surge of carbon dioxide from human activities is predicted to cause Earth's climate to warm appreciably.
"What we can say that is relevant is that these sort of drought cycles are common and most of the climate models predict increased aridity in continental interiors in the future," Clark said.
"One could speculate that the droughts could be all that much worse when you realize that it's not only climate change from changing CO2 content in the atmosphere, but also this natural variability out there that we don't fully understand."
Another drought on the Great Plains would wipe out agriculture over a large area and drive lots of people to migrate away from the region. It would also reduce river flow down the Missouri and Mississippi rivers and that would reduce the navigability of those rivers for shipping as well as reduce the amount of water that could be taken from the rivers for irrigation.
Whether or not humans reduce their emissions of green house gasses sooner or later the Earth is going to go through some large regional and eventually even global climate shifts. Those of us who live long enough to be around when rejuvenation therapies are developed will likely then live long enough to witness many large changes in Earth's climate.
However, not all the natural changes lying in our future will come to pass. At some point humans are going to start intervening to prevent some changes while perhaps in other cases humans will engineer other desired changes. Expect to see less desert in the future as some nations decide they would rather cause local climate changes to make their deserts more hospitable to human habitation. This will lead to international disagreements when other nations calculate how conversion of deserts to forests in some regions will cause changes they do not like in their own regions.
Sami Solanki, Professor at the Federal Institute of Technology in Zurich Switzerland, says the Sun has been burning more brightly over the last 60 years than over the previous 1090 years.
“We have to acknowledge that the Sun is in a changed state. It is brighter than it was a few hundred years ago, and this brightening started relatively recently – in the last 100 to 150 years. We expect it to have an impact on global warming,” he told swissinfo.
The sun's brightness hasn't changed much over the last 20 years. But it has been brighter for the last 60 years than it has been at any time in the last 1,150 years.
According to scientists, the Sun’s radiance has changed little during this period. But looking back over 1,150 years, Solanki found the Sun had never been as bright as in the past 60 years.
The team studied sunspot data going back several hundred years. They found that a dearth of sunspots signalled a cold period - which could last up to 50 years - but that over the past century their numbers had increased as the Earth's climate grew steadily warmer. The scientists also compared data from ice samples collected during an expedition to Greenland in 1991. The most recent samples contained the lowest recorded levels of beryllium 10 for more than 1,000 years. Beryllium 10 is a particle created by cosmic rays that decreases in the Earth's atmosphere as the magnetic energy from the Sun increases. Scientists can currently trace beryllium 10 levels back 1,150 years.
Over the past few hundred years, there has been a steady increase in the numbers of sunspots, a trend that has accelerated in the past century, just at the time when the Earth has been getting warmer.
During the Medieval maximum of 1000-1300 there was an extremely large Sunspot which is believed to have warmed the Earth higher than normal. There were no accurate measurements of the weather to call upon during this time but the discovery and colonization of Greenland by Eric the Red supports this hypothesis. Eric was exiled from Iceland for manslaughter and sailed west discovering Greenland. He then led many ships, filled with people who wanted to make a fresh start, to this new land. For 300 years Greenland flourished, new communities settled, trade with other countries grew, and the population increased. Around 1325 the climate cooled down considerably, people started to abandon the northern settlements. By 1350 glaciers covered the northern settlements, and the southern most settlements were dying out as well.
The Sporer minimum of 1400-1510 and the Maunder minimum of 1645-1715 were each known as a "little ice age." They were both droughts in Sunspot activity, and a link to a time of abnormally cold weather on Earth. In addition to finishing off the Greenland colonies, the Sporer minimum showed increased rates of famine in the world, and the Baltic Sea froze solid in the winter of 1422-23. Some of the more notable effects of the Maunder minimum included the appearance of glaciers in the Alps advancing farther southward, the north sea froze, and in London there was the famous year without a summer where it remained cold for 21 consecutive months.
The evidence supports the effect of Sunspot activity on the Earth's climate, but that is only one of many areas that effects us on Earth. On March 13,1989 a large Sunspot ignited powerful flares that tripped the circuit breakers a generator station. The started the collapse of the Quebec power system and left people without power for hours to days. These same flares damaged several man made satellites, and caused smaller outages all over the U.S and Canada. There are countless other times when large Sunspots have effected similar damage to various electrical systems on Earth.
The Sun could start going through a down trend in sunspot activity at any time. We could find ourselves back in a state similar to the Maunder Minimum with decades of much colder weather. Or sunspot activity could increase to an even higher level and temperatures could rise more than the amount some models project as a consequence of higher atmospheric carbon dioxide.
My guess is that the chances are greater for a reduction in sunspot activity than for an increase. Why? Most of the time the planet Earth is in an ice age. This is suggestive of the possibility that the Sun just doesn't put out enough heat to keep the Earth out of ice ages most of the time. Also, the higher sunspot activity reported above is at the high end of an over 1,000 year period. Therefore the odds seem greater that we will have more future years with lower sunspot activity than with higher sunspot activity.
My further guess is that a reduction in sunspot activity would cause more harm to humans than a further increase in sunspot activity. A decrease could put large amounts of farm fields out of production and would reduce the useful length of the growing seasons for other fields. The freezing over of rivers and seas along with snows and ice would interfere with transportation more than higher temperatures would.
Also, my guess is that it would be easier to reflect away excessive sunlight than to try to replace the heat lost in another cold period like the Maunder Minimum. For example, to reduce the sunlight hitting the Earth during high sunspot periods we could genetically engineer plankton to produce more of the chemicals they generate to make clouds. We could also try to engineer more snowfall around glaciers to increase the areas covered by reflective white snow. We could also paint more human structures white to reflect back sunlight.
But imagine trying to generate enough energy to make up for a reduction in solar radiation during a period of low sunspot activity. We could take some steps to compensate for reduced solar radiation. For instance, we could paint all human structures black to make them absorb more light to raise ground temperatures. Also, we could try to develop some really large scale methods for coating ice sheets with dark coverings. It may also be possible to reduce cloud cover by seeding clouds to cause rains to fall in areas where the water is needed.
One option for a period of reduced sunspot activity would be to increase the release of green house gasses. But it is not clear that the planet contains enough fossil fuels to make that possible. We'd probably have to shift heavily toward the use of coal. But even that might not generate enough greenhouse gasses to compensate for a period of no sunspots.
As long as humans do not mess it up, the Earth's climate is set at fair for the next 15,000 years. That is according to information extracted from the oldest ice core ever drilled.
That already shows that the amount of CO2 in the air during stage 11 was similar to our own pre-industrial level3. As Earth's orbit was much the same then, this suggests that stage 11 was very like our present balmy interglacial, and that without the effects of global warming we would probably have to wait some 16,000 years for another ice age. "It's a wonderful window into the future as well as the past," says Raynaud.
While some scientists are interpreting these new results to mean that a new ice age is still a long way off one ice-core scientist from the University of Colorado sounds less certain about our ability to predict the next ice age.
Recovery of a new ice core in Antarctica that extends back 740,000 years -- nearly twice as long as any other ice core record -- is extremely important and will help scientists better understand the Earth's climate and issues related to global warming, according to a University of Colorado at Boulder professor.
The new ice core, announced June 9 by the European Project for Ice Coring in Antarctica, or EPICA, reaches far enough back in time to give scientists "a first shot at looking at climate and greenhouse gases during interglacial periods when humans had nothing to do with climate change," said geological sciences Professor James White.
"This has the potential to separate the human-caused impacts from the natural and place it in a much clearer context," he said.
A commentary on the new ice core written by White will appear in the June 11 edition of the journal Science. One of the world's leading ice-core scientists, White has conducted dozens of studies of ice cores from both Antarctica and Greenland. He is director of the CU-Boulder Environmental Studies program and a fellow of the CU-Boulder Institute of Arctic and Alpine Research.
Concern about the effects of human-caused greenhouse gas releases into the atmosphere has led many scientists to conclude that humans are changing the atmosphere. Drilling deep into polar regions and extracting ice cores can tell scientists about the Earth's climate during the distant past, before technology and farming became a factor in releasing such gases.
Ice cores can tell scientists about concentrations of greenhouse gases such as carbon dioxide and methane, dust levels in the atmosphere, volcanic eruptions and estimates of temperatures and precipitation.
"We're living in an unusual time," White said. "In the past 430,000 years, the percentage of time that the climate was as warm as it is today is quite small, about 5 percent to 10 percent, and before that time, it appears to never have been that warm.
"Humans have been active in messing with the carbon cycle for a long period of time," he said. "Here we are warming the planet, while at the same time, climatologists will tell us that we are perhaps long overdue for a glacial period."
The average number of years spent in a warm period between ice ages -- like our current climate -- has been about 6,000 years, White said. But the current interglacial period has lasted for 12,000 years. Only one other interglacial period has exceeded that length of time -- it lasted for about 28,000 years -- and it happened about 450,000 years ago.
The EPICA core will provide the first complete record of that period and will allow scientists to study it in more detail than ever before, White said.
"Ice cores are the ultimate preservation tool for information about past environments," White said. "Whatever happens on the Earth that changes the atmosphere -- the big events -- is recorded in the ice and it stays there."
Another exciting aspect of the EPICA ice core is that at 740,000 years, scientists have not yet reached the bottom of the ice sheet, he said. "The possibility of a million-year ice core is out there and a million years ago is a really significant period in the Earth's climate history."
Prior to a million years ago, there was no large-scale glacial/interglacial pattern and the Earth had a more steady climate controlled by the sun, he said. Something happened at around that time to cause the Earth to have larger variations in its climate.
"One of our biggest scientific questions is: Is glaciation overdue?" White said. "For our future it is very important that we understand how these huge glaciers start."
The fact that we are overdue, by historical standards, for another ice age may be due to human intervention. See my previous post Farming And Forest Destruction Prevented Ice Age 5000 Years Ago.
The more we understand the climate the better we are going to be able to predict both naturally-caused and human-caused future changes in the climate. At the same time, our ability to intervene in the climate to engineer different outcomes will increase. Along with our increasing understanding and ability to intervene will come increased demands for climate engineering to either reverse the effects of other human interventions or to prevent natural trends from playing out.
If the theory that human farming practices have already prevented an ice age then this will have a profound effect upon the debate about human influences on climate. A radical program to neutralize human influences on the climate would literally bring on an ice age. Only a small minority of environmental radicals are going to support an effort to produce that outcome.
Dr. David A. Siegel of the University of California, Santa Barbara Institute for Computational Earth System Science and Dierdre Toole now at the Woods Hole Oceanographic Institution have demonstrated with their research on the Sargasso Sea southeast of Bermuda that a gas released by phytoplankton causes cloud formation and reduces the amount of sunlight reaching the Earth.
Phytoplankton are tiny, single-celled floating plants. They inhabit the upper layers of any natural body of water where there is enough light to support photosynthetic growth. They are the base of the ocean's food web, and their production helps to regulate the global carbon cycle. They also contribute to the global cycling of many other compounds with climate implications.
One of these compounds is a volatile organic sulfur gas called dimethyl sulfide or DMS. Scientists had previously theorized that DMS is part of a climate feedback mechanism, but until now there had been no observational evidence illustrating how reduced sunlight actually leads to the decreased ocean production of DMS. This is the breakthrough in Toole and Siegel's research.
Ultraviolet radiation causes the phytoplankton to release DMS.
According to their research, it appears that phytoplankton produce organic sulfur compounds as a chemical defense from the damaging effects of ultraviolet radiation and other environmental stresses, in much the same way as our bodies use vitamins E and C to flush out molecules that cause cellular damage.
Siegel and Toole found that ultraviolet radiation explained almost 90 percent of the variability in the biological production of DMS. They showed that summertime DMS production is "enormous," and that the entire upper layer of DMS content is replaced in just a few days. This demonstrates a tight link between DMS and solar fluxes.
"The significance of this work is that it provides, for the first time, observational evidence showing that the DMS-anti-oxidant mechanism closes the DMS-climate feedback loop," said Siegel. "The implications are huge. Now we know that phytoplankton respond dramatically to UV radiation stresses, and that this response is incredibly rapid, literally just days."
The effects of ozone layer thinning will be partially offset by an increase in cloud cover caused by increased DMS release.
As the Earth's ozone shield thins and greenhouse gases increase, higher ultraviolet radiation will reach the surface layer of the oceans. The findings indicate that phytoplankton will then produce more DMS in response to this increased ultraviolet radiation, causing increasing cloudiness and mitigating the effects of global warming. However, Siegel is careful to note that while the process may mitigate global warming it will not reverse the trend.
Keep in mind that much of global warming is not caused by more ultraviolet light getting through the ozone layer. Carbon dioxide and methane work by reducing heat loss. However, if methods could be developed to increase phytoplankton production of DMS then the resulting cloud cover would still reduce the amount of warming.
Be sure to click through and look at the image of contrails over California from space seen with two infrared wavelengths. The jet engine contrails have have caused most or all the warming observed in the United States for nearly 20 years.
NASA scientists have found that cirrus clouds, formed by contrails from aircraft engine exhaust, are capable of increasing average surface temperatures enough to account for a warming trend in the United States that occurred between 1975 and 1994. "This result shows the increased cirrus coverage, attributable to air traffic, could account for nearly all of the warming observed over the United States for nearly 20 years starting in 1975, but it is important to acknowledge contrails would add to and not replace any greenhouse gas effect," said Patrick Minnis, senior research scientist at NASA's Langley Research Center in Hampton, Va. The study was published April 15 in the Journal of Climate. "During the same period, warming occurred in many other areas where cirrus coverage decreased or remained steady," he added.
It can all be blamed on the airplanes. I picture an Airplane sequel where they fly around in an airplane that unleashes heat waves wherever they go. Elaine could tell Ted Stryker she doesn't know how to surf while right below them a huge wave crashes into Miami while the Miami Vice soundtrack plays. Perhaps Don Johnson could put in a cameo appearance.
Minnis determined the observed one percent per decade increase in cirrus cloud cover over the United States is likely due to air traffic-induced contrails. Using published results from NASA's Goddard Institute for Space Studies (New York) general circulation model, Minnis and his colleagues estimated contrails and their resulting cirrus clouds would increase surface and lower atmospheric temperatures by 0.36 to 0.54 degrees Fahrenheit per decade. Weather service data reveal surface and lower atmospheric temperatures across North America rose by almost 0.5 degree Fahrenheit per decade between 1975 and 1994.
Will the Kyoto Accord enthusiasts now all swear off flying to international conferences on global warming? Will they swear off flying in general? Let me go out on a limb here and predict they won't.
The development of agriculture thousands of years ago may already have prevented an ice age. So when a certain songwriter "dreamed of 747s over geometric farms" she was simultaneously dreaming of two causes of global warming.
Update: Over on the Crumb Trail blog back40 makes the great point that as we discover different causes of climate change this serves as a lesson that the various solutions proposed by the fear-mongers are naive and premature.
Climate management is much more complex than politicians and journalists realize. It isn't a simple matter of being more frugal in some activity such as burning fuels. The worst thing we could do is to squander our wealth and energy on a large and ineffective program.
A better argument can be made for publicly denouncing the Moonbats of the world than for denouncing skeptics. By whipping up populist authoritarian fervor about the wrong problems and the wrong solutions, wealth, energy and attention has been squandered that could have been more productively applied to useful research into causes and possible management techniques.
I keep arguing forr effort to do research on alternative energy sources because the results would provide many other benefits aside from effects on climate change. By contrast, a worldwide system of regulation and taxes to reduce fossil fuel usage would exact a huge cost in reduced economic growth, would centralize power, and lead to squabbles between nations over fairness of allocations for carbon dioxide emissions. It would also not even do all that much to reduce climate climate change. By contrast Nobel Laureate Richard Smalley's proposal a $10 billion per year for development of alternative energy sources would eventually lead to the development of technologies which would be spread by market forces. Make a cheaper source of energy that just happens to be cleaner and the markets will see to it that it displaces more costly and polluting energy forms. A precedent for this is the way market forces caused the displacement of coal by oil and then natural gas for many uses.
The succession of discoveries about the importance of jet contrails, farming, solar radiation changes, and other factors also argues for a larger effort in climate research to develop a much greater understanding of climate.
Jonathan Gregory, a climatologist at the University of Reading, UK, says global warming could start runaway melting on Greenland within 50 years, and it will "probably be irreversible this side of a new ice age". The only good news is that it a total meltdown is likely to take at least 1000 years.
We desperately need rejuvenation therapies that will allow us to live long enough to witness the complete melting of Greenland.
A meltdown of the massive ice sheet, which is more than 1.8 miles thick, would raise sea levels by an average seven yards, threatening countries such as Bangladesh, islands in the Pacific, and parts of Florida.
Further complicating the models are the contradictory effects a warmer climate may have on polar ice sheets. As temperatures rise, evaporation from the surrounding oceans will increase, sending more moisture inland. This will increase snowfall over high-elevation accumulation zones. On the other hand, the simultaneous increase in summer rains could accelerate the melting. So the net effect of increased precipitation is hard to predict.
One final uncertainty is the fate of the Gulf Stream, which delivers warm tropical water to the North Atlantic and keeps Europe much warmer than it would otherwise be. Some scientists believe that the Gulf Stream is weakening in response to the massive influx of fresh water from shrinking glaciers. If it became weak enough, they say, Greenland would chill down again and its ice sheet might stabilize.
In a nutshell we don't really know what is going to happen. But even if the prediction of melting is correct that does not mean humans in the future will not find a way to prevent the melting. It is inevitable (failing the destruction of the human race) that climate engineering techniques capable of preventing huge ice masses from melting will be developed because the amount of scientific knowledge and technological capability will be so great in the future that even willful climate modification will become possible. One approach might be to find ways to increase the reflectivity or albedo of the seas around Greenland so that they absorb less sunlight and therefore become cooler. Another approach would be to develop devices that float on the surface and use wave energy to squirt water into the air. This would increase evaporation and hence could increase precipitation and ice build-up if used selectively during winters and upwind of Greenland.
Some people are clearly not worried about the prospect of flooding coastal cities decades hence. Not the least bit bothered by the idea that he was decreasing the albedo of an iceberg and causing it to melt more rapidly Danish artist Marco Evaristti went searching for the ideal iceberg off the Western Greenland and painted it red.
Facing temperatures of minus 23 degrees C (minus 9 degrees F), it took about two hours for the 40-year-old artist to paint the exposed tip of the iceberg, which was about 900 square meters (1,080 square yards) in size.
He had a team of 20 people to help him and obviously at least 21 people are not afraid to accelerate the melting of a massive chunk of ice. See his red iceberg and an even nicer high resolution red iceberg picture on Evaristti's website.
Researchers at UW-Madison including Michael Kaplan and Brad Singer along with researchers at Woods Hole Oceanographic Institution have show that the last ice age also happened in South America.
Using a technique to read the changes imposed by cosmic rays—charged, high-energy particles that bombard the Earth from outer space—on atoms found in the mineral quartz, the researchers were able to precisely date a sequence of moraines, ridge-like glacial features composed of an amalgam of rocks, clay, sand and gravel. Their results show that glacial ice in South America reached its apex 22,000 years ago and had begun to disappear by 16,000 years ago.
"The team has applied an innovative investigative technique to an untapped archive of data on natural climate variability to help reduce uncertainty in our knowledge of how Earth's climate works," said David Verardo, director of the National Science Foundation’s (NSF) paleoclimate program, which funded the research. NSF is the independent federal agency that supports fundamental research and education across all fields of science and engineering.
The work is certain to help researchers of past climates unravel the mysteries of ice ages that periodically gripped the planet, Verardo said, but it also will help those trying to understand current and future climate change by helping to determine the natural causes of changes in the Earth's climate system on a global scale.
"We've been able to get quite precise ages directly on these glacial deposits," says team leader Brad Singer, of UW-Madison. "We found that the structure of the last South-American ice age is indistinguishable from the last major glacier formation in the Northern Hemisphere."
And, said Kaplan, "During the last two times in Earth's history when glaciers formed in North America, the Andes also had major glacial periods."
The results address a major debate in the scientific community, according to Singer and Kaplan, because they seem to undermine a widely held idea that global redistribution of heat through the oceans is the primary mechanism that drove major climate shifts of the past.
The implications of the new work, say the study authors, support a different hypothesis: Rapid cooling of the Earth's atmosphere synchronized climate change around the globe during each of the last two glacial epochs.
"Because the Earth is oriented in space in such a way that the hemispheres are out of phase in the amount of solar radiation they receive, it is surprising to find that the climate in the Southern Hemisphere cooled off repeatedly during a period when it received its largest dose of solar radiation," says Singer. "Moreover, this rapid synchronization of atmospheric temperature between the polar hemispheres appears to have occurred during both of the last major ice ages that gripped the Earth."
There are big heat conveyor flows in the world's oceans. One fear of climatologists is that global warming might cause a halt to the flow of warm water into the North Atlantic due to a decrease in salinity caused by glacier melting and changing precipitation patterns. This would cause a dramatic cooling especially in Europe and even in parts of North America. However, while the possibility of that scenario still exists these researchers are arguing that a halt in the heat conveyor probably didn't cause the glacial periods. This research shows the glacial periods happened in South America as well and the halt in the conveyor would not have caused the same cooling effect in South America that it would have caused in Europe.
Most of the debate about climate change today is centers around the question of how is humanity changing the world's climate and how big an effort should be made to reduce the human impact on climate. However, if humanity survives long enough then eventually humans are going to have to decide whether to try to stop much larger climate changes that have non-human causes. When the Earth begins to descend into another ice age should humanity intervene to stop it? Some naturalists believe that processes that have non-sentient causes should be considered sacred and not to be tampered with. In their minds that which is natural is morally superior and changes caused by sentient minds are inherently sinful. My guess is that if humanity lives long enough to witness the beginning of the next ice age then artificial intelligences will ally with the majority of the human race in favor of an intervention to prevent the ice age.
Kenneth R. Minschwaner of the New Mexico Institute of Mining and Technology and Andrew Dessler of the University of Maryland have found that warming caused by carbon dioxide build-up will cause less evaporation of water and therefore less additional warming than climate modellers have been assuming. (same article here and both have graphic illustrations)
A NASA-funded study found some climate models might be overestimating the amount of water vapor entering the atmosphere as the Earth warms. Since water vapor is the most important heat-trapping greenhouse gas in our atmosphere, some climate forecasts may be overestimating future temperature increases.
In response to human emissions of greenhouse gases, like carbon dioxide, the Earth warms, more water evaporates from the ocean, and the amount of water vapor in the atmosphere increases. Since water vapor is also a greenhouse gas, this leads to a further increase in the surface temperature. This effect is known as "positive water vapor feedback." Its existence and size have been contentiously argued for several years.
Ken Minschwaner, a physicist at the New Mexico Institute of Mining and Technology, Socorro, N.M., and Andrew Dessler, a researcher with the University of Maryland, College Park, and NASA's Goddard Space Flight Center, Greenbelt, Md, did the study. It is in the March 15 issue of the American Meteorological Society's Journal of Climate. The researchers used data on water vapor in the upper troposphere (10-14 km or 6-9 miles altitude) from NASA's Upper Atmosphere Research Satellite (UARS).
Their work verified water vapor is increasing in the atmosphere as the surface warms. They found the increases in water vapor were not as high as many climate-forecasting computer models have assumed. "Our study confirms the existence of a positive water vapor feedback in the atmosphere, but it may be weaker than we expected," Minschwaner said.
Water evaporation will contribute to warming but not as much as previously predicted.
In most computer models relative humidity tends to remain fixed at current levels. Models that include water vapor feedback with constant relative humidity predict the Earth's surface will warm nearly twice as much over the next 100 years as models that contain no water vapor feedback.
Using the UARS data to actually quantify both specific humidity and relative humidity, the researchers found, while water vapor does increase with temperature in the upper troposphere, the feedback effect is not as strong as models have predicted. "The increases in water vapor with warmer temperatures are not large enough to maintain a constant relative humidity," Minschwaner said. These new findings will be useful for testing and improving global climate models.
While gradual warming is the scenario most widely discussed possible future climate scenario there is a real possibility that the Earth's climate could undergo a rapid cooling initiated by natural processes or human-caused changes.
While policymakers have worried long and hard about global warming, which might raise Earth's temperature 1.4 to 5.8 degrees C by century's end, a growing body of evidence suggests natural forces could just as easily plunge Earth's average temperatures downward. In the past, the planet's climate has changed 10 degrees in as little as 10 years.
For example: Regional and global climates have undergone quick and dramatic changes even after what would appear to be only gentle prodding by natural influences, Dr. Eakin says. In many cases, that prodding has been far less severe than the changes humans have wrought via industrial emissions of carbon dioxide.
We have not seen sudden drastic climate changes in the lifetimes of anyone now living. But the Little Ice Age temperature dips have happened as recently as the US Revolutionary War period and into the 19th century.
The general trends reflected in the tree-ring record include cooler conditions in the early 1700s, followed by warming that started mid-century. An abrupt cooling occurred in the late 1700s and continued for much of the 1800s. The coldest period was between the 1830s and 1870s, after which a steadily increasing warming trend began.
We shouldn't be completely suprised if the Earth's climate suddenly begins to undergo some sudden change in the coming years and decades. It has happened often enough in the past that it is really a question of when and not if this will occur.
Although ozone slows plant growth, the beneficial effect of the carbon dioxide more than compensates for this effect, Leakey found. His unpublished results predict an increase in soy yields of 13% by 2050. US farmers currently plant about 150 million acres of soybean a year.
The following press release emphasies that the increased plant growth in the presence of higher CO2 is not enough to take all the CO2 out of the atmosphere. But the fact that the trees and plants grow more rapidly is economically valuable.
OAK RIDGE, Tenn., Feb. 16, 2004 -- Trees absorb more carbon dioxide when the amount in the atmosphere is higher, but the increase is unlikely to offset the higher levels of CO2, according to results from large-scale experiments conducted at Oak Ridge National Laboratory and elsewhere.
"Some people have used carbon dioxide fertilization to argue that this is a boon of the fossil fuel era and that it will lead to greater agricultural yields and carbon sinks," said Richard Norby of the Department of Energy's ORNL. "Some recent experiments, however, have suggested that there will be no lasting effect of carbon dioxide fertilization. As is often the case, the truth may lie in between."
Norby is among several scientists participating in a panel discussion titled "CO2 Fertilization: Boon or Bust?" Feb. 16 at the American Association for the Advancement of Science annual meeting in Seattle.
For the last six years, Norby and colleagues at ORNL have examined the responses to elevated carbon dioxide levels in a stand of sweetgum trees a few miles from ORNL. The experiment consisted of pumping tons of carbon dioxide into the plots, raising the concentration of carbon dioxide in the tree stand from the ambient level of about 370 parts per million to 550 ppm, and studying the effects.
In every year since the FACE project began, net primary productivity, which is the total amount of carbon dioxide fixed into organic matter such as leaves, stems and roots, has been higher in plots given extra carbon dioxide. The average increase has been 24 percent, and there is no indication that the increase will not continue. But, Norby notes, while his colleagues have observed a sustained increase in leaf photosynthesis, the response to carbon dioxide fertilization would not be apparent if only above-ground growth were measured. Wood production increased significantly during only the first year of treatment.
While Norby and colleagues have learned a great deal about above-ground allocation of carbon dioxide, in recent years they have focused their efforts on impacts on fine roots and soil sequestration of carbon dioxide. Fine root production has increased substantially in response to elevated carbon dioxide.
Fine roots are important for water and nutrient uptake, but they have a short life and their carbon returns to the soil within a year. Initial results suggest that the increase in carbon supply to fine roots has increased the carbon content of the soil. Norby cautions, however, that the positive effect of carbon dioxide fertilization is insufficient to halt the rising level of atmospheric carbon dioxide.
If some types of forest trees will grow more rapidly then higher atmospheric CO2 holds the prospect of lowering timber costs and hence of lowering housing and furniture costs.
SEATTLE -- A futuristic Duke University simulation of forest growth under the carbon dioxide-enriched atmosphere expected by 2050 does not reinforce the optimism of those who believe trees can absorb that extra CO2 by growing faster, said a spokesman for the experiment.During seven years of exposure to carbon dioxide concentrations 1½ times higher than today's, test plots of loblolly pines have indeed boosted their annual growth rates by between 10 and 25 percent, found the researchers. But "the highest responses have been in the driest years, and the effect of CO2 has been much less in normal and wet years," said William Schlesinger, a professor of biogeochemistry and dean of Duke's Nicholas School of the Environment and Earth Sciences.
These counterintuitive findings suggest that nitrogen deficiencies common to forest soils in the Southeastern United States may limit the abilities of loblolly pine forests to use the extra CO2 to produce more tissues as they take in more of the gas, he said.
"In a dry year trees naturally grow less so the amount of nitrogen doesn't make any difference," he said. "In a wet year, when there's plenty of water, the amount of nitrogen does make a difference." Tree growth depends on the availability of nitrogen, which foresters routinely add to Southeastern soils in the form of fertilizer when they plant trees, he added.
One advantage the plants may have in dry years is that with more CO2 in the atmosphere the leaves do not have to open their pores as much to let in the CO2. This reduces water loss from evaporation and allows plants to grow in dry environments. This explanation has been put forward to explain plant growth into the Negev desert in Israel.
The really bad news? More poison ivy:
Meanwhile, some other species in Duke's CO2-bathed forest plots have grown at faster rates than the loblolly pines, scientists report. Still-unpublished data shows 70 percent growth increases for poison ivy, according to Schlesinger.
It seems likely that the growth increase caused by higher CO2 will differ by tree species. Some will experience larger increases in growth rates and others will benefit from higher CO2 to a lesser extent. Also, since water is more of a rate-limiting factor in some areas and less in other areas the extent of the benefit of higher CO2 in terms of faster growth in lower water conditions will be greater in some geographic regions and less in other regions. Higher CO2 probably will increase total tree cover in drier areas and may even make it possible to grow trees into deserts as appears to be happening with the Negev.
Another factor to consider: It should be possible to select for or genetically engineer crop plants that will grow even faster in higher CO2 conditions. So the extent of the benefit of high CO2 seen with existing crop plants understates the size of the benefit likely to be achievable in the longer run.
Of course, higher atmospheric CO2 levels will cause many other effects. If higher CO2 raises global temperatures it could change precipitation patterns, total global precipitation, length of growing seasons (generally longer), wind patterns, and other many other factors. How will all this work out in terms of benefits and costs? It seems impossible at this point to hazard a guess that will have any degree of accuracy. But it seems clear that rising atmospheric CO2 will generate not just costs but benefits as well.
Soot particles may be twice as bad as the greenhouse gas carbon dioxide in contributing to global warming, suggests a new study.
Grains of soot deposited in snow have also caused about one-quarter of the observed rise in global surface temperature since 1880, suggests the model by James Hansen and Larissa Nazarenko. The pair examined how soot particles affect the atmosphere when they darken snow and ice.
Note that when soot causes ice to melt that makes previously white surface areas become darker and hence to absorb more sunlight and radiate more heat. Hence, the melting of ice and packed snow raises temperatures and causes more ice to melt.
Hansen, director of NASA's Goddard Institute for Space Studies, and Nazarenko, a staff associate there, found soot is twice as potent as carbon dioxide in changing global surface air temperatures in the Arctic and the Northern Hemisphere.
The NASA Goddard Space Flight Center press release page has nice graphs and animations that make clicking here worth the trip.
Hansen and Larissa Nazarenko, both of the Goddard Institute and Columbia University's Earth Institute, found soot's effect on snow albedo (solar energy reflected back to space), which has been neglected in previous studies, may be contributing to trends toward early springs in the Northern Hemisphere, thinning Arctic sea ice, melting glaciers and permafrost. Soot also is believed to play a role in changes in the atmosphere above the oceans and land.
"Black carbon reduces the amount of energy reflected by snow back into space, thus heating the snow surface more than if there were no black carbon," Hansen said.
Soot's increased absorption of solar energy is especially effective in warming the world's climate. "This forcing is unusually effective, causing twice as much global warming as a carbon-dioxide forcing of the same magnitude," Hansen noted.
Hansen cautioned, although the role of soot in altering global climate is substantial, it does not alter the fact greenhouse gases are the primary cause of climate warming during the past century. Such gases are expected to be the largest climate forcing for the rest of this century.
The researchers found that observed warming in the Northern Hemisphere was large in the winter and spring at middle and high latitudes. These observations were consistent with the researchers' climate model simulations, which showed some of the largest warming effects occurred when there was heavy snow cover and sufficient sunlight.
Hansen and Nazarenko used a leading worldwide-climate computer model to simulate effects of greenhouse gases and other factors on world climate. The model incorporated data from NASA spacecraft that monitor the Earth's surface, vegetation, oceans and atmospheric qualities. The calculated global warming from soot in snow and ice, by itself in an 1880-2000 simulation, accounted for 25 percent of observed global warming. NASA's Terra and Aqua satellites are observing snow cover and reflectivity at multiple wavelengths, which allows quantitative monitoring of changing snow cover and effects of soot on snow.
While this may not be immediately obvious this report seems like good news. Why? Because it is a lot cheaper to reduce soot emissions than to reduce carbon dioxide emissions. If a substantial source of warming can be cancelled out cheaply then that buys time (assuming it really is necessary to intervene in the first place) to develop technologies that will allow carbon dioxide emissions to be reduced at much lower cost.
Soot is not the only warming pollutant which would be cheaper to reduce than carbon dioxide. Methane also has warming effects and reduction of methane emissions could be done cheaply. A reduction in methane emissions would have the added benefit of reducing ozone at ground level.
Reduction in soot emissions would also yield substantial health benefits. A recent paper published in the medical journal Circulation C. Arden Pope of Brigham Young University and colleagues have found that particulate pollutants increase the incidence of cardiopulmonary diseases and ischemic heat attack.
Tiny particles of pollutants emitted by automobiles, power plants and factories significantly increase the risk of dying from cardiovascular disease in the United States, according to a study led by Brigham Young University epidemiologist Arden Pope.
The research was published in "Circulation: Journal of the American Heart Association" on Dec. 15. Statistical links between air pollution and increased mortality were reported by Pope and others in the mid-1990s. In March of 2002 he and colleagues reported associations between air pollution and lung cancer, as well as the broad category of cardiopulmonary disease, which includes both heart and lung ailments.
The new study narrows the latter finding by identifying a strong link between particulate air pollution and ischemic heart disease (the type that causes heart attacks), and also a link between pollution and the combined category of irregular heart rhythms, heart failure and cardiac arrest. It also suggests general biological pathways through which pollution might cause these diseases that lead to death – increased inflammation and nervous system aberrations that change heart rhythm.
"Not only do we show a statistical link between particulate air pollution and these types of heart disease," Pope said, "but we see specific patterns that are consistent with mechanistic pathways that may help explain how air pollution causes those diseases. The study discusses recent advancements in cardiovascular medicine that have explored the role of inflammation in the development and progression of atherosclerosis. The study results are consistent with recent findings that air pollution may provoke low-grade pulmonary inflammation, accelerate the progression of atherosclerosis, and alter cardiac function. These results add biological plausibility that air pollution really is a risk factor for heart disease."
The EPA has declared that the annual average level of PM2.5 particles in the air should not exceed 15 micrograms per cubic meter. Pope's study showed that each 10 micrograms-per-cubic-meter increase in fine particulate air pollution is accompanied by an 18-percent increase in risk of death from ischemic heart disease and a 13-percent increase in risk of death from altered heart rhythm, heart failure or cardiac arrest.
Further analysis also showed higher risks associated with air pollution for former and current smokers – 26 percent and 94 percent, respectively. Pope notes that "smoking is clearly a much larger risk factor, but air pollution increases the risk of cardiovascular death in non-smokers and seems to add additional risk to smokers."
Pope emphasized that the study's findings are "good news." Since the early 1980s, the annual U.S. average of PM2.5 has dropped from 21 to 14 micrograms per cubic meter.
If we consider both the uncertainties in the current climate models (witness the sudden discovery of the greater importance of soot outlined above) and the advantages both in costs and in health benefits for the reduction in warming pollutants other than carbon dioxide it seems foolish to rush into a major reduction in carbon dioxide emissions. There are easier pickings that provide more benefits. A reduction in particulates would reduce heart disease and cancer and make us healthier in other ways. A reduction in methane emissions would reduce ozone pollution and therefore also reduce harm to the lungs and other organs.
Now, almost 12 years later, Dr. Hansen says that too much emphasis has been placed on the effects of fossil fuels combustion. Instead, Hansen says that warming over the past century was mostly driven by gases such as methane and chlorofluorocarbons.
In a report in Proceedings of the National Academy of Sciences, he says, "We suggest that a strategy to slow global warming focus on reducing air pollution, especially tropospheric (ground level) ozone, methane and black carbon particles." The report notes that the growth rate of non-carbon greenhouse gases has "declined in the past decade."
Dr. Hansen states that global warming can be prevented "without any economically wrenching actions." He says that "human health and ecological costs of these pollutants are counted in billions of dollars in the United States and impacts are reaching devastating levels in the developing world. A strategy focused on reducing these pollutants, which are not essential to energy production, should unite the interests of developed and developing nations."
Update: See a previous work by Hansen and colleagues from May 2003. Note that soot emissions are high in areas that are economically less developed.
Black carbon or soot is generated from traffic, industrial pollution, outdoor fires and household burning of coal and biomass fuels. Soot is a product of incomplete combustion, especially of diesel fuels, biofuels, coal and outdoor biomass burning. Emissions are large in areas where cooking and heating are done with wood, field residue, cow dung and coal, at a low temperature that does not allow for complete combustion. The resulting soot particles absorb sunlight, just as dark pavement becomes hotter than light pavement.
Update II: On a related note Richard Muller discusses the limitations of current methods to estimate historical temperatures.
The disagreement is not political; most of it arises from valid issues involving physics and mathematics. First the physics. An accurate thermometer wasn’t invented until 1724 (by Fahrenheit), and good worldwide records didn’t exist prior to the 1900s. For earlier eras, we depend on indirect estimates called proxies. These include the widths of tree rings, the ratio of oxygen isotopes in glacial ice, variations in species of microscopic animals trapped in sediment (different kinds thrive at different temperatures), and even historical records of harbor closures from ice. Of course, these proxies also respond to other elements of weather, such as rainfall, cloud cover, and storm patterns. Moreover, most proxies are sensitive to local conditions, and extrapolating to global climate can be hazardous. Chose the wrong proxies and you’ll get the wrong answer.
When you hear some claim that a particular year is the hottest year on record for x many hundreds or thousands of years take it with a grain of salt. As Muller's article shows, there are unresolved questions about how to accurately estimate historical temperatures in previous centuries on planet Earth.
Atsumu Ohmura has discovered that the lights are going out all over the world.
"It's an uncomfortable one," says Gerald Stanhill, who published many of these early papers and coined the phrase global dimming. "The first reaction has always been that the effect is much too big, I don't believe it and if it's true then why has nobody reported it before."
That began to change in 2001, when Stanhill and his colleague Shabtai Cohen at the Volcani Centre in Bet Dagan, Israel collected all the available evidence together and proved that, on average, records showed that the amount of solar radiation reaching the Earth's surface had gone down by between 0.23 and 0.32% each year from 1958 to 1992.
The few experts who have studied the effect believe it's down to air pollution. Tiny particles of soot or chemical compounds like sulphates reflect sunlight and they also promote the formation of bigger, longer lasting clouds. "The cloudy times are getting darker," says Cohen, at the Volcani Centre. "If it's cloudy then it's darker, but when it's sunny things haven't changed much."
The explanation most popular among atmospheric scientists is that soot and other pollutants are blocking visible and infrared light from reaching the surface of the planet. But another possibility is that global warming is causing an increase in cloud cover by increasing the amount of airborne water or dust. If pollution is the cause then efforts to reduce particulate pollution may be starting to cause a reduction in the dimming effect. But it could be that the US and Europe will reduce their particulate pollution while South and East Asia increase theirs.
The reduction in light reaching the surface is probably reducing plant growth in areas closer to the poles. At the equator carbon dioxide (CO2) and water are more likely to be rate-limiting factors for plant growth. But note that as CO2 levels rise that has the tendency to allow plants to grow faster by both increasing the amount of CO2 available and also by reducing the amount of water that plants have to lose when they try to absorb CO2 gasses and hence higher CO2 reduces plant needs for water.
Pollution regulations effectively could be used as a climate engineering tool. Mandate a more rapid reduction in particulate pollution and the effect will probably be to increase the amount of sunlight that reaches the Earth's surface. That could increase plant growth in regions closer to the poles while also probably increasing surface evaporation from the oceans and hence probably lead to an increase in precipitation. That would be beneficial in some areas but detrimental in other areas.
The scale of human activity has gotten so large that we inevitably change the climate to some extent. We do not know yet just how much we are changing the climate because we do not know what the climate would be like in our absence. Since the human population is growing and parts of the world are rapidly industrializing human influence on the climate looks set to grow even further. But since there are so many human activities that cause climate effects and since some of those effects cancel each other out (at least to some extent) any effort to reduce only a single pollutant or to reduce the impact of only a single method of modifying our environment will have the effect of strengthening the impact of other things that we do.
In a paper published in the scientific journal Climate Change Dr. William Ruddiman argues that humanity prevented an ice age that would otherwise have begun about 4,000 or 5,000 years ago.
Both should have continued declining through the present day, leading to lower temperatures, and a new ice age should have begun 4,000 to 5,000 years ago, Dr. Ruddiman said. Instead, levels of carbon dioxide reversed 8,000 years ago and starting rising again. The decline in methane levels reversed 5,000 years ago, coinciding with the advent of irrigation rice farming.
If this argument is correct then humanity, by engaging in rice farming and deforestation, reversed a trend of decline in atmospheric carbon dioxide and methane and, by doing so, prevented a cooling trend that would have brought on another ice age. This is a strong argument in favor of climate engineering.
All throughout the natural history of planet Earth the development of new life forms has altered the climate. The only difference between human intervention and intervention by other life forms is that humans have a higher level of sentience and hence can develop an awareness of the effects of their actions. But that awareness by itself is not a sufficient reason to refrain from acting in ways that alter the climate.
There is no stable state of climate that humans are disturbing. The climate has gone through many large changes because of variations in solar output, gradual changes in Earth's orbit, volcanic eruptions, asteroid strikes, and large assortment of other factors. It is likely do so again.
Humans could develop the ability to engineer the climate. Attempts to do so run the risk of causing some huge unforeseen outcome. But the biggest argument against climate engineering on a global scale is that most changes would hurt some nations while providing benefits to others. Warm the planet and Russia and Canada become more livable places. But perhaps other places will get less needed rains or will witness failures of crops due to shifting rain patterns or temperature changes. Any attempt to reach a global agreement on climate engineering would be hard to achieve unless humanity was faced with a disaster that only climate engineering could prevent.
Update: BBC science correspondent Richard Black says Ruddiman's theory is plausible.
Professor Ruddiman, of the Department of Environmental Sciences at Virginia, believes this 10,000-year warming added almost a degree Celsius to the global average temperature.
This though is a radical departure from existing theories about climate change and will inevitably be debated by other researchers.
But there is supporting evidence, and it is consistent with what we know about deforestation and farming today.
The idea is likely to spark debate among climate scientists, but at least one sceptic is already changing his mind. "I hadn't fully appreciated the actual magnitude of the human disturbance," says Thomas Crowley, who works on global warming at Duke University in Durham, North Carolina. "I've been thinking more and more that Ruddiman is on to something."
Technological advances in coming decades will gradually increase the ability of humans to engage in intentional climate engineering. Instead of having climates engineered as an unintentional side effect it will become possible to modify regional and global climates with conscious intent. Climate changes naturally and our ability to predict how the climate will change without human intervention will increase along with our ability to predict how much and what sorts of changes will come as side effects of human interventions. Those who oppose all human intervention in climate trends will eventually be faced with computer climate models that will be able to show with fairly high probability what the world climate would be like right now or 50 years from now had humans not developed agriculture or any other technology. If the gap between what is and what would have been turns out to be really large the opponents of human-caused climate change are then going to have to explain why we shouldn't engineer the climate to be more like it would have been if we had never developed agriculture. Ice age anyone? If not, why not?
Grassland ecosystems could become wetter as a result of global warming, according to a new study by researchers from Stanford University and the Carnegie Institution of Washington. This surprising result, published in the Proceedings of the National Academy of Sciences (PNAS), contradicts numerous climate models predicting that higher temperatures could dry out natural landscapes, including grasslands.
The study, to be posted the week of Aug. 4 on PNAS Online, is based on a two-year field experiment conducted in the grassy foothills above Stanford's main campus. Instead of causing the soil to dry up, the experiment revealed that higher temperatures actually increased soil moisture by as much as 10 percent.
"Warming accelerates evaporation, so we expected warmer to mean drier," said lead author Erika S. Zavaleta, a former Stanford doctoral student now on the faculty of the University of California-Santa Cruz. "We were surprised to find that warming actually increased moisture in our grassland plots during those critical weeks in late spring at the end of the growing season, when moisture shapes which plant species prevail. We traced this unexpected moisture increase to the plants themselves."
The discovery that higher temperatures can significantly dampen soil is at odds with several climate models that predict that global warming will make grassland ecosystems drier, not wetter. Those models are based on the assumption that higher temperatures will increase the amount of water that evaporates from the soil and the surface of living plants -- a process called "evapotranspiration."
At the Jasper Ridge site, most soil moisture evaporates through plants. But during the course of the experiment, researchers discovered that warming caused the early demise of numerous grasses and wildflowers. In fact, some experimental plots that were exposed to higher temperatures suffered the premature loss of 17 percent of their green vegetation. Since evapotranspiration only occurs through living plants, the fact that so many died early could explain the unexpected rise in soil moisture, the authors noted.
"In California grasslands, plants control most of the water exiting the system by transpiring water through their leaves until they die," Zavaleta said. "Simulated global warming accelerated the death of the dominant grasses in our plots, leaving slightly more water in the soil for other species like oaks and summer wildflowers to use. This doesn't mean climate change is good for California grasslands, but it reinforces the importance of paying attention to how plants and animals could modify its effects."
If higher temperatures kill off some of the plants but leave more moisture for the other plants then what are the effects on the remaining plants? Do they stay healthy longer during dry periods? It is not clear what the net effect is of the higher temperatures. One effect might be to cause a change in the ratios of species of plants in any given area to select for more heat-resistant plants.
Note that independent of the heat effect the plots that were exposed only to higher CO2 also had more moisture in their soil. That result, while not unexpected due to previous research, is also interesting in light of another report previous posted here: Rising Carbon Dioxide Causing Forests To Expand Into Deserts. A hotter planet with more CO2 in the atmosphere may turn out to be a much greener planet overall.
A pair of scientists argue that variations in the amount of cosmic ray flux hitting the Earth's atmosphere is the biggest cause of changes in Earth's climate.
Global warming will not be helped much by efforts to reduce carbon dioxide emission into the atmosphere, say two scientists who have studied the matter.
Dr. Nir Shaviv, an astrophysicist from the Racah Institute of Physics of the Hebrew University of Jerusalem, and Prof. Jan Veiser a geochemist at the University of Ottawa in Canada and Ruhr University in Germany, say that temperature variations are due more to cosmic forces than to the actions of man.
In a recent article published in GSA Today (the journal of the Geographic Society of America) and described in Nature, Shaviv and Veiser tell of their studies illustrating a correlation between past cosmic ray flux – the high-energy particles reaching us from stellar explosions -- and long-term climate variability, as recorded by oxygen isotopes trapped in rocks formed by ancient marine fossils. The level of cosmic ray activity reaching the earth and its atmosphere is reconstructed using another isotopic record in meteorites.
The study showed that peak periods of cosmic rays reaching the earth over the past 550 million years coincided with lower global temperatures, apparently due to the way that the cosmic rays promote low-level cloud formation (hence blocking out sun warming). No correlation was obtained, however, with the changing amount of atmospheric carbon dioxide.
The conclusion of the two scientists is, therefore, that celestial processes seem to be the dominant influence on climate change, and that increased carbon dioxide release, while certainly not beneficial, is only secondary to those forces which are beyond our control.
In practical terms, says Dr. Shaviv, "The operative significance of our research is that a significant reduction of the release of greenhouse gases will not significantly lower the global temperature, since only about a third of the warming over the past century should be attributed to man." Thus, say the scientists, the Kyoto accord of 1997 -- which was aimed at tackling the global warming phenomenon through limitations on carbon dioxide -- is not the panacea some thought it would be.
Taking the long-range view, Dr. Shaviv and Prof. Veiser believe that fluctuations in cosmic ray emissions account for about 75 percent of climate variation throughout the millennia. They acknowledge that this position pits them against prevailing scientific opinion, which still places a heavy emphasis on the negative role of greenhouse gases.
More specifically the authors assert that the long-term "warming effect of CO2" is "potentially lower" than generally thought. They say the carbon dioxide factor would appear to have a minimum impact of 1.9C on sea temperatures rather than the 5.5C projected in certain worst-case scenarios.
The Christian Science Monitor has an interesting article on the increasing recognition among climate scientists of the role that variations in solar activity play in changes in Earth's climate.
Other researchers found that the sun appears to display variations in its magnetic field and solar wind that span longer time scales. According to some researchers, during the past century, the strengths of the solar wind and the sun's magnetic field have doubled.
The cosmic-ray proposition holds that when the sun's magnetic field and the field generated by the solar wind increase, Earth is increasingly shielded from cosmic rays. These charged particles are thought to have the ability to seed cloud formation by triggering processes at the micro level that generate the nuclei around which water vapor condenses. Thus, if Earth's "shield" had been strengthening over the past century, it should have led to lower average cloud cover and warmer temperatures.
Will the sun increase or decrease its output overall in the 21st century? It is not inconceivable that some day humans may seek to engage in large scale measures to compensate for trends in solar output. Imagine, for instance, that the sun began again to behave has it did in the late 17th century. Variations in solar output in are believed to have been at least partly responsible for the Little Ice Age.
Because the sun is the ultimate source of Earth's warmth, some researchers have looked to it for an answer. In the 1970s, solar researcher John Eddy, now at Saginaw Valley State University in Michigan, noticed the correlation of sunspot numbers with major ups and downs in Earth's climate. For example, he found that a period of low activity from 1645 to 1715, called the Maunder Minimum, matched perfectly one of the coldest spells of the Little Ice Age.
Judith Lean, a solar physicist at the Naval Research Laboratory in Washington, estimates that the sun may have been about a quarter of 1 percent dimmer during the Maunder Minimum. This may not sound like much, but the sun's energy output is so immense that 0.25 percent amount to a lot of missing sunshine -- enough to cause most of the temperature drop, she says.
NASA climate researcher Eric Shindell believes the decrease in overall Earth temperatures were fairly small during the Maunder Minimum but the changes were much more drastic in the North Atlantic and Europe.
Shindell noted that the effects of this period of a dimmer sun were concentrated more regionally than globally. "Global average temperature changes are small, approximately .5 to .7 degrees Fahrenheit (0.3-0.4C), but regional temperature changes are quite large." Shindell said that his climate model simulation shows the temperature changes occurring mostly because of a change in the Arctic Oscillation/North Atlantic Oscillation (AO/NAO).
Once photovoltaic cells and other means of producing energy become cheap the release of CO2 into the atmosphere will become optional. One can imagine scenarios in which solar output dropped enough that a large scale increase in CO2 produced by burning fossil fuels might usefully compensate for some of the decrease in solar radiation. On the other hand, if solar output increased one can also imagine strategies which could be used to take CO2 out of the atmosphere. Energy produced by solar cells or nuclear reactors could be used to drive chemical processes that fixed carbon from the atmosphere into a solid form.
This reminds me of an idea that I think deserves more attention than it gets: Since hydrogen is a less dense form of energy than hydrocarbon liquids it is a poor substitute for hydrocarbons in vehicles. An alternative would be to use energy from photvoltaics or nuclear reactors to drive the fixing of carbon from atmospheric carbon dioxide to hydrogen extracted from water (effectively to do what chloroplasts do in plants but without any oxygen in the resulting compounds). The resulting hydrocarbons could be used as an energy source for vehicles. This would produce what would be, in effect, an artificial carbon cycle that would operate in parallel with the natural one.