A recent scientific conference looked into methods for climate engineering to counteract global warming. (same press release here)
The symposium, called “Macro-engineering options for climate change management and mitigation” is at the Isaac Newton Institute in Cambridge from 7-9 January.
“We urgently need to explore the feasibility of imaginative new ideas for reducing global warming in the future, either by slashing carbon dioxide emissions, or by counteracting its effects, if we are to avoid dangerous climate change”, says Professor John Shepherd, a Director of the Tyndall Centre.
Proposed options for reducing carbon dioxide pollution currently include underground burying of liquefied carbon dioxide; disposal in the sea; fertilising its absorption by marine algae; reflecting the sun’s rays in the atmosphere; and stabilizing sea-level rise. These and other macro-engineering ideas will be evaluated against a strict set of criteria, including effectiveness, environmental impacts, cost, public acceptability, and reversibility. All of these options go beyond the conventional approaches of improving energy efficiency and reducing carbon intensity by using more renewable energy sources, and may be needed in addition to these conventional approaches.
“Because of the urgency of implementing climate-change management, more innovative approaches to the mitigation of climate change might be needed. This is really a big thought experiment, to critically evaluate which macro-engineering options might be feasible and worth pursuing” comments John Shepherd. “Some of the macro-engineering options which have been suggested are big and rather scary, and some may even appear to be crazy. That is precisely why they should be evaluated – and if necessary dismissed – as soon as possible, so that society can decide which should be developed as serious options for future use, if & when they are needed.”
“Most of these macro-engineering options are not yet in the mainstream for climate policy, but the mere fact that they have been suggested places an obligation on scientists from many disciplines to explore their feasibility and evaluate their consequences and their wider implications” comments Shepherd.
Instead, the scientists backed more way-out systems for reflecting the sun's rays back into space. Plan A would float thousands of bubble-making machines across the world's oceans to send huge amounts of salt spray into the atmosphere. The trillions of tiny droplets would make the clouds bigger, whiter, and more reflective -- enough, in theory, to shut down several decades worth of global warming.
Plan B would flood the stratosphere with billions of tiny metal-coated balloons, "optical chaff" to backscatter the sun's rays. Most sophisticated of all, Plan C would assemble giant mirrors in orbit, ready to be positioned at will by a global climate controller.
The BBC reports on 4 major categories of conceivable climate engineering approaches.
- "sequestering" (storing) carbon dioxide, for example in the oceans, by removing it from the air for storage, or by improved ways of locking it up in forests
- "insolation management" - modifying the albedo (reflectivity) of clouds and other surfaces to affect the amount of the Sun's energy reaching the Earth
- climate design, for example by long-term management of carbon for photosynthesis, or by glaciation control
- impacts reduction, which includes stabilising ocean currents by river deviation, and providing large-scale migration corridors for wildlife.
A test of one technique for climate engineering is currently underway. A German scientific team led by Victor Smetacek set sail on January 21, 2004 on board the research ship Polarstern headed for the Antarctic to try a massive experiment at salting the ocean with iron to encourage phytoplankton to remove carbon dioxide (CO2) from the atmosphere.
The team plans to dissolve an iron sulphate solution in a in a 150-200 square-kilometre patch of the Southern Ocean, near Antarctica, where currents are expected to keep the iron within a limited area. The team will then monitor the growth of phytoplankton from a helicopter, and examine which kinds of algae and other creatures flourish for a period of eight to ten weeks.
If and when global warming becomes a net harm to humanity climate engineering may turn out to be a far more cost-effective way to mitigate it. If atmospheric carbon dioxide levels could rise without causing global warming then there would be benefits in terms of faster growing crops and also from the growth of plants into areas that are currently deserts. Israeli scientists attribute the expansion of a forest into the Negev desert to the results of higher atmospheric CO2 levels.
Update: Even without the formation of an international committee to choose climate engineering projects the impact of human activity on the climate is going to become a far more politically contentious subject. The reason is that advances in climate science will improve our ability to model and predict how each human activity will change the climate all over the world. So, for instance, it will become possible to know how much the burning of coal in China increases or decreases rainfall in Saharan Africa. It will become possible to know how much car exhaust fumes in the United States change temperatures in Europe in different seasons. It will become possible to know how cutting down rainforests in Brazil or Indonesia affects rainfall in Peru or Australia. As people become more aware of how activities by other people cause impacts in their own lives then it seems reasonable to expect animosities between countries to rise as a consequence.
If normal human activities in each country come to be seen as causing problems in other countries then it will not take the formation of an international climate engineering organization for climate changes to be the source of focused resentments and animosities. To the extent that science causes the weather to seem less like a consequence of acts of God and more like the consequence of acts of humans climate will become a source of political strife and possibly terrorism and war.
Razib from Gene Expression has beaten me to posting about this Scientific American article on the proposed use of phytoplankton to take CO2 out of the atmosphere in order to prevent global warming:
Working from this theory, Green Sea Venture postulates that fertilizing 16 million square miles of the Southern Ocean with 8.1 million tons of iron would zero out the world contribution to atmospheric CO2 increases from burning fossil fuel--2.2 gigatons of carbon per year. "The potential of the oceans is so great that we ought to do the experiments that allow us to decide whether or not it is a worthwhile undertaking for climate control," says Lee Rice, president of the company. "But the scientific data are not conclusive." No one has yet been able to measure how much carbon sinks into the deep ocean, because the detritus sinks slowly. So that is the focus of an, as-yet-unscheduled, 5,000 square mile fertilization experiment, which the company would help fund. "In addition," says Rice, "there is a real gap between the scientific clarity and how to do this practically, since you do need to verify how much carbon has been sequestered in order to get paid." His investors, he asserts, are willing to wait for science's judgment about whether commercial activity is warranted.
However, I want to post on this because I want to use it as a jumping off point to talk about an issue that I think is worth thinking about: future prospects for climate engineering. The most dramatic experiments made in climate engineering have been with the attempts to control hurricanes in Project Stormfury:
It was on the heels of Hurricane Camille barreling into the Gulf Coast regions of Mississippi and Alabama when Hurricane Debby was seeded on a couple of occasions over the two day period of August 19-20, 1969. Each time the storm was seeded, sustained winds were reduced significantly.
The first time, winds dropped 31 percent while the second time, they only dropped 15 percent. The apparent success with Debby helped fuel new projects, and improvements in technology. In particular, Hurricane Hunter aircraft, which went up dramatically during the 1970s.
Ultimately though, Project Stormfury was cancelled in 1980 since the team was unable to clearly ascertain whether or not the seeding efforts were really causing storms to weaken, or the systems just became victims of the environment around them. Nevertheless, the work done did bear some fruit as forecasters and scientists alike were able to learn a great deal from their research, and it has helped them improved forecasting accuracy.
The NOAA web site has a graphical depiction of Project Stormfury Hypothesis. Here's another article on Project Stormfury. My own take on the skepticism expressed in the article is that that science is all about experimentation. If an attempt at cloud seeding was attempted on a much larger scale (say bump up the seeding by a couple of orders of magnitude) using today's technology then the seeding approach could be much more thoroughly tested.
Some people are going to oppose climate engineering because, for reasons that are religious in character, they believe that humans do not have the right to intervene in nature to cause climate scale changes. Others will oppose it out of fear of unintended consequences. However, even if we reject the sort of moral philosophy that views natures as something that should not be tampered with and even if we may some day know enough to be able to predict all major consequences there will still be another argument against climate engineering: any intentional shift in weather that causes changes in one place will cause changes throughout the world. As a consequence of those changes (no matter how large or small) there are bound to be winners and losers throughout the world as well. For instance, a slight increase or decrease in rainfall in other countries will either increase flooding or lead to a reduction of crop yields.
Of course industrialization is already causing small scale climate changes around the world. Greenhouse gases are only one of the ways that this is happening. Agriculture and cities change how much dust gets generated and, as was demonstrated by the airline shutdown in America after the 9/11 attacks, jet contrails change temperature ranges. Many other examples can be cited. But these activities are carried out for reasons other than intentional climate change and most governments support the right of their own peoples to carry out these various climate-changing activities. Few human activities are currently carried out for the sole purpose of climate change (cloud seeding for rain being the only one I can think of). So people will still draw a distinction between intentional and unintentional climate change.
One might be able to argue that climate engineering to dampen the energy of hurricanes would cause changes that are smaller than the changes we are already causing. However, unless the dampening down will reduce the hurricane into a mild storm the danger is that the hurricane might change course and in doing so cause damage to different towns and cities. The problem is that while the total amount of damage may be less the people who suffer it will claim they have a right not to have artificially induced damage inflicted on them as a consequence of reducing a much larger amount of damage elsewhere.
So does that mean that climate engineering is beyond the realm of political feasibility? I can see one reason why the vast bulk of the population of many countries may decide to support it: to reverse a sudden, large, and painful change in the climate. I've previously posted a link on ParaPundit.com about the possibility that the Atlantic Conveyor that brings heat up from the Gulf Stream to keep the North Atlantic and Europe much warmer could stop running if the salinity of the north Atlantic drops too low (and as you can see by clicking thru it is dropping).
It is not clear at this point that human greenhouse gas emissions are what are behind the changes in the north Atlantic salinity. We must bear in mind that large climate variations happen naturally. The Atlantic Conveyor may stop running and start running for reasons unrelated to human activity. Still, if it did stop running lots of people would decide that human activities at least contributed to the event and hence they would conclude that the event was "unnatural" (ignoring that humans are part of nature and that it is false to believe that consciousness and sentience makes us unnatural). The ability to label a large and sudden climate change as "unnatural" would open the door widespread support for an unnatural intervention to get the Conveyor running again.
It is my view that any large sudden change in climate will be labeled as unnatural. Never mind that large sudden changes in climate happen for natural reasons (ie not as a consequence of activities carried out by humans). Human impacts on the world are large enough that any large climate change can plausibly be blamed on human activity. The objections to climate engineering therefore are easier to overcome because in many cases climate engineering can be portrayed as an attempt to reverse what humanity has caused. This makes the future prospects for climate engineering much more likely that they might seem at first glance.