December 25, 2007
Has Earth Climate Warming Trend Stopped?

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)

Dr. Whitehouse says the world might be cooling due to reduced solar energy output.

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.

Share |      Randall Parker, 2007 December 25 09:43 PM  Climate Trends

Ken said at December 26, 2007 2:33 AM:

1998 - a strong el Nino year. Yet even starting with that higher than usual temperature in what is noisy data, it still shows a warming trend - others have run the source data through spreadsheets and confirmed that trend, even starting from that exceptionally high temperature year. So the claim that the trend is flat is disputed. And anyone who picks a short series with exceptional highs or lows in it, with a series that does have noise in it, when a full, longer series is there to use is probably trying to deceive. I also think talking of more and less solar activity tends to be deceptive - sunspot activity may be at a temporary low, but solar irradiance - the measure of how much solar energy reaches the Earth - is not, so you get the first suggesting the sun is cooling, yet the latter is rising. Neither appear to be determinants of the measured change, the variations only able to account for climate change if you dismiss and ignore all the other science and inflate the solar influence. I'm glad to see you haven't accepted the entirety of the claim warming stopped completely uncritically but with reputable sources saying the trend is still warming it's disappointing that you seem to accept a news report that says it's stopped.

Martin Thulenberg said at December 26, 2007 6:07 AM:

Good point about Chinese soot. In fact, it is the soot from China blackening the northern ice cap that is partially responsible for increased melting. Most of the rest is due to cyclic changes in ocean and wind circulation patterns.

The temperature trend is to a very slight cooling since 1998. And 1998 was not the warmest, rather it was 1934 or 35. So what we actually see is a flat trend from 1935 through 2007. If you look at satellite records, the cooling trend is even more pronounced.

Our sun has some interesting things planned for us. Things that climate modelers have not anticipated.

Dr Coles said at December 26, 2007 7:44 AM:

U.S. Senate Report: Over 400 Prominent Scientists Disputed Man-Made Global Warming Claims in 2007.

bill r said at December 26, 2007 8:28 AM:

Could you expand on the claim that "it still shows a warming trend"? Simple cherry picking of 1998 is wrong, but both the Hadley and GISS series show "non-significant" slopes for the 1998+ series (both are in the .01-.02 degree/year range) If one runs a change point algorithm (e.g. bcp in R with a low prior) 1997-1998 gets picked as a changepoint. Reputable sources might say that it is still warming, but the published data do not support just that hypothesis. Looking at the GISS data the 1975-1998 run-up looks similar to the 1910-1940 run-up, which was followed by a 35 year plateau/decrease.

Ed Voll said at December 26, 2007 9:45 AM:

I know everyone has a bias but I'm hoping they realize the focus on US and Bush as the environmental enemy will shift to the newly industrializing countries. In any case the 'news' on one year variations tells us very little except how much study needs to be done on complex issues and one-shot solution like ethanol could be a worse disaster for the poor of the planet.

K said at December 26, 2007 3:54 PM:

The comments that soot is more important than acknowledged seem right to me. The difference in hemisphere heating has been puzzling. Volcanic activity doesn't seem adequate this time.

Far more interesting than man made CO2 - which, after all, can be controlled if it becomes imperative - is what is happening on the sun. The continuing delay in the next solar cycle certainly will affect our global temperatures sooner or later. Exactly what that effect will be is quite another matter. NASA now says the cycle will commence within six months. Could be. I think the absence of the cycle would simplify modeling; the less that is changing the better you can focus on what is changing.

Ten years since 1998 isn't much. It certainly doesn't prove or disprove AGW tenets. I do wish politics wasn't slanting discussion and sometimes the facts themselves. But what can you expect when AGW will be the greatest event and problem in history if the prevailing view is correct?

Randall Parker said at December 26, 2007 4:11 PM:


An extremely accomplished scientist (who prefers to remain nameless on this subject owing to his aversion to the politicized nature of this topic) at an institution that looks down on MIT (who can guess where I mean) told me the mathematical models for climate are all crap. They can't predict anything. Ergo in his mind they aren't science. Science predicts. He works to develop predictive models. He's got physics and chemistry chops. He wants predictability. I agree. Predictability is good. Confirmed models are good.

That leaves me thinking we have to place more importance on the actual empirical data. Well, I want the empirical data to be unambiguous. Being able to see a strong trend is really handy. But at my level of skill and knowledge in this area the data doesn't seem unambiguous.

How noisy are temperature measurements? How high of quality are the data on temperatures around the globe? Can we be undergoing a warming trend that is really strong and still see the temperature fall from one year to the next just from noise?

At the same time, in the face of ambiguous data I do not counsel paralysis. We don't have to be 100% certain in order to take precautionary measures. Some steps (e.g. build nukes and wind mills) seem justified for other reasons (less pollution and the threats of Peak Oil, Peak Natural Gas, Peak Coal. The data on fossil fuels depletion (at least for oil and natural gas) seems far stronger than the data on global warming.

David Govett said at December 26, 2007 4:25 PM:

I remember the global cooling scare in the 1970s, when scientists, academia, and the mainstream media colluded in bamboozling the American public. Future generations will consider this another Middle Age of science, when intimidation and peer pressure prevailed over the scientific method.

TTT said at December 26, 2007 5:48 PM:

The Sun is weakening? I blame George W. Bush.

Ken said at December 27, 2007 1:55 AM:

Randall, I'd forgotten how popular this site is with people who doubt or outright disbelieve AGW. FWIW the warming has stopped claim is disputed, with the relevant graphs here, and the graphs, starting with an exceptionally warm year ie cherry picked to best show warming has stopped still show warming. I admit to being less capable of disputing the nuts and bolts of this than I would like - I am not a climate scientist. But then I don't think anyone here is. Ultimately I have to rely on the institutions that do the relevant science. My disappointment is that you appeared willing to accept the opinion of news reporters ahead of them on this important matter. The solar activity (sunspot intensity/solar cycle length, not solar irradience) forcing hypothesis appears to be mostly correlation but lacks clear causation, whereas the current AGW thinking has solid physics and chemistry - and includes solar irradience in it's calculations - as it's basis. My understanding is the predictions from climate modelling have been fairly accurate to date - not perfect, but not too wide of the mark, but I have to say you should be arguing this with NCAR, CRU, NAS and working scientists. I certainly won't be persuaded by people telling me they are all deliberately biased - ie acting fraudulently to get specific outcomes - or that a bit of media hype in the seventies with next to nothing in the scientific literature is any way comparable to the volumes of science done over the past few years.

Feel free to remain skeptical - it's important that people do - but we are talking about science that has every peak science body agreeing it's sound. It needs more than someone anonymously telling you he thinks this or that. If it's so clear that the methods of prediction used are flawed the flaws need pointing out in scientific journals, subjected to review and critique by other scientists. If such doubts are simply used as a tool of delay, outside the community of working scientists, your accomplished scientist is doing science a disservice.

epobirs said at December 27, 2007 5:09 AM:

Yet it remains that none of the modelers can accurately demonstrate the reasons for past climate. If they cannot model something with a known outcome, how can their predictions be at all trusted? Especially when there are groups using this as a bid to gain extraordinary powers to control the lives of others.

david said at December 27, 2007 9:25 AM:

I believe that the article states that the temperature increase in recent years has been less than expected if CO2 emissions are the cause of global warming. It does not say that temperature increases have stopped, it does say that the greenhouse effect caused by CO2 emissions should have produced higher temperatures in the period since 1998. In other words CO2 emissions continued to rise but temperatures did not show a related increase. The point here is that the answer may be significantly more complex and involve much longer time periods than those covered by the available data. Data from a hundred years or so may be no more relevant than data from the last ten but we have to keep looking because to ignore the potential for catastrophy would be irrational.

jim moore said at December 27, 2007 1:52 PM:

I was my understanding that global average temperature is a very noisy signal. Increases in the night time temperature, average temperature at the poles and decreasing time from first frost to spring thaw were all much less noisy indicators of the greenhouse effect. Does anyone know if these other indicators have also stopped changing?

Randall Parker said at December 27, 2007 3:37 PM:


1) The news reporter you refer to has a Ph.D. in astrophysics. I made this clear because it is obviously relevant. Yet you dismiss him because he's a reporter. Gimme a break. He's probably much smarter than both of us. He knows a lot of hard science stuff.

2) There are highly credible doubters on global warming - at least on whether we scientifically know. Again, I know this from conversations. I know this from reading.

3) You should be clear there's an important difference between doubt and disbelief. As I see it the case for warming is still unproved. Why is it unproved? Partly because scientists lack the tools needed to prove it. Their models are unverified and definitely wrong. They can't predict. Science is about prediction.

4) The absolute believers turn me off. I live in a world of probabilities. If the believers instead said we had a substantial probability of a problem and ought to buy ourselves insure I'd be ready to agree. But the people of faith turn me off.

5) The case for running out of fossil fuels is stronger than the case for global warming. We ought to put as much effort into verifying the fossil fuels reserves as we put into climate research. The amount of coal left is probably the biggest climate question we face. We might be getting close to peak CO2 emissions because of depleting oil and natural gas reservoirs. Or maybe we have enough coal to keep CO2 emissions rising even as oil and natural gas production plunge? I really want to know the answer to that question and not just due to the global warming debate.

jim moore,

I've never read a good thorough treatment on how noisy the temperature signals are. I've read more narrow critiques of particular sampling locations. But nothing really good about the overall data set. I'm quite curious to know more.

MT said at December 27, 2007 4:55 PM:

Climate models are simply not credible enough to bet the future on. Science is prone to its "fashions" just as much as politics, movies, television, and music. Global cooling was once the fashion, now it's global warming. People who think the science is settled and the debate is over, are only listening to one side of the conversation. Not the most informed side, either. It's entertaining to watch the editorial staffs of the most fashionable science journals fall all over themselves to prove which is the most "consensus correct." Fashionable, as always.

Mark said at December 27, 2007 6:23 PM:

Well, the treeline has moved north in the Arctic and glaciers have disappeared, so some warming has occurred. A good thing, too. Otherwise, we would statistically have already seen the beginning of the next Ice Age.

John S Bolton said at December 27, 2007 6:57 PM:

I found this on American Spectator:
"Another Perspective
Not So Hot
By Patrick J. Michaels
Published 12/27/2007 12:07:49 AM

If a scientific paper appeared in a major journal saying that the planet has warmed twice as much as previously thought, that would be front-page news in every major paper around the planet. But what would happen if a paper was published demonstrating that the planet may have warmed up only half as much as previously thought?

Nothing. Earlier this month, Ross McKitrick from Canada's University of Guelph and I published a manuscript in the Journal of Geophysical Research-Atmospheres saying precisely that.

Scientists have known for years that temperature records can be contaminated by so-called "urban warming," which results from the fact that long-term temperature histories tend to have originated at points of commerce. The bricks, buildings, and pavement of cities retain the heat of the day and impede the flow of ventilating winds."

Rather than 'follow the money', I say follow the power-greed nexus.
If officials are asking for more power, this opens up all sorts of possibilities for picking and choosing, funding
just that which is suited to enhance power. Officials and their professoriate, are not to be trusted when they stand to gain power, just as one distrusts those who say that the government should intervene to raise their price structure.

Ken said at December 27, 2007 9:48 PM:

Randall, we are talking about an opinion piece in a newspaper, and given that he has a PhD, Dr Whitehouse ought to know how much scientific credibility attaches to those. Is it really necessary to point to others with PhD's with the opinion that the sunspot/solar activity hypothesis has no legs WRT recent global warming? The PhD in and of itself is not sufficient to mean he must be right. Dr Whitehouse appears to be a decent writer of popular books that introduce people to various aspects of Astronomy. If he's been active in research, I'm not aware of it. I'd be happy to be pointed to publications in science journals by him, but beyond a quick google scholar search which has several different David Whitehouse's, none seeming to be the one above, I'm not wasting my time chasing them down. Not a reporter as such - my mistake, but opinion piece writers don't necessarily rate higher in the credibility department - and he has been a science news editor. He knows how to write convincingly, but holding this guy's opinions up as reason to doubt AGW doesn't do you credit.
I think the preponderance of scientific evidence is saying it's highly likely we've got AGW. Absolute certainty? I never said so, but I also doubt we're going to get conclusive proof except the hindsight version. Alternative explanations for the growing body of data -like the sunspot/solar activity one -just don't appear to cut it. That they fail to gain acceptance might be considered proof of bias. I think it's more likely they just don't stand up to close scrutiny - I believe most scientists do their work honestly and diligently, especially given that their work is subject to ongoing scrutiny. Doing poor work is likely come back to haunt them.
And I think the claim the models are "definitely wrong" and "can't predict" could be disputed too. Don't think I'll bother attempting it here, now. Would links to anything on that cause you to reassess? Are you sure you aren't too attached to that spot on the fence? What kind of proof would get you to shift?

Engineer-Poet said at December 28, 2007 7:29 AM:
Rather than 'follow the money', I say follow the power-greed nexus. If officials are asking for more power, this opens up all sorts of possibilities for picking and choosing, funding just that which is suited to enhance power.
There's a rather simple solution to that:  make it clear that the solution will be a carbon tax (rather than tradeable permits given to major emitters for a discount or even for free).  This doesn't give the officials any role in determining who does what.

It also doesn't give industries or utilities free money from selling allocations given them gratis.  They're bound to lobby for a system which allows them to charge rents, but nothing stops us from publicizing this as a money-grab.

Ken said at December 28, 2007 1:02 PM:

Randall, there is a lot about your blog and posts that I like, a lot of stuff that I think has a sound basis. I think choosing that particular opinion piece as something significant wasn't justified, but to be fair, you have applied some critical thought to the issues raised.

On the matter of noise - if my non-PhD 2cents worth is worth anything - clearly a lot of the "noise" is not randomness; el Nino changes the heat balance between ocean and atmosphere in a major way. That we are currently seeing la Nina conditions, the converse condition to el Nino, has to be significant. If more heat or less is retained by oceans, there will be changes to atmospheric temperatures and flow on effects re evaporation and humidity, cloud cover, rainfall, the heat balance of land and ice masses. Some will be shorter term, some longer. I don't think the spread of atmospheric temperature values means the amount of energy reaching the planet is similarly spread. If more energy is making it's way into deeper ocean, the effects will just be longer term, and show less in that temp series. But it ought to show in ocean temp measurements. Now, estimating the overall heat balance for the planet needs to take into account such variations. ie they need to be incorporated into the models to improve their accuracy. As far as I know that's what they do.

I know there are some smart people who don't accept that such modelling can do the job- that they are inherently unable to reproduce the complex energy flows with any worthwhile accuracy. Other smart people think they can do the job and try and incorporate as much detail as possible - the modelling being works in progress, rather than any complete "proof". My understanding of the details of that is unclear, except that they claim it's real physics and chemistry being modelled. I don't consider myself capable of making such an assessment myself. In this I must rely on the experts and institutions such as the National Academy of Sciences. If some consider my position that of "faith" in such institutions, I can't say they are wrong, but I suspect very few people are in a position to make such assessments themselves, and so are also relying on "faith" of some sort.

JMG3Y said at December 28, 2007 10:56 PM:


My complaint with the Whitehouse piece is that he did not include specific information on his data or analysis sources for those interested in such things to pursue for themselves. His statements "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." and "The fact is that the global temperature of 2007 is statistically the same as 2006 as well as every year since 2001." clearly indicate that he is looking at something specific but what? On the other hand, I recognize his right not to do so in an opinion piece but I wish he had and doing so would have increased credibility of the piece.

With respect to modeling, I wonder if the interrelationships between factors determining climate are so complex, due to the networks of lagged positive and negative feedbacks, that they quickly exceed the capacity of the human brain, that the only way for even experts to gain a reasonably correct comprehension of the climate system is through modeling. In the limited modeling of complex biological systems that I've done, some results were surprising and counter intuitive when individually well understood components were linked together to represent the system. The process of model building itself was very useful because it required making explicit all the otherwise fuzzy concepts that one has about how the system functions. In the end, we are all modelers, having in our heads implicit models, right or wrong (ala "A Private Universe"), of our part of the world that we use to make predictions about its function.

Ken said at December 29, 2007 4:53 PM:

Randall, I don't want to outstay my welcome here, but I would like to explain why I have trouble accepting the sunspot/solar activity hypothesis as any kind of alternative explanation for climate change - my own reason rather than something I've read and am parroting.

The solar activity thing comes from comparing graphs of such activity with global temperature and finding some correlation. Now, there's nothing wrong with comparing graphs - that can be revealing – but this is a case of looking at one influence in isolation. Again nothing wrong with that but it means there’s a major leap to impute too much to it. Clearly from above discussion we have to say that global surface air temperature graphs alone, revealing as they are, are just part of the picture, that variations in those graphs sometimes (not always) have relatively clear causes. The physics of gas molecules, how they absorb and re-emit energy, is well established, so there is sound reason to consider them as part of the explanation for temperature changes in the atmosphere. There are aerosols, man made and natural, there are albedo changes. There are ocean circulation changes such as El Nino/Southern Ocean Oscillation. So, where are they in the solar activity hypothesis? If other effects are estimated to be nonexistent or negligible, the proponents need to explain why that is the case, especially given that there is sound physics and chemistry to give them the causation part in climate change. So they need to subtract out the influences that are clearly there before making that comparison – except it’s a lot more complex than overlaying graphs or adding and subtracting with the underlying data.

Now, there may be a link to cloud formation, but it's very tenuous, I don’t think it’s enough to pin any number values on. I have no problem with scientists seeking such causation and, through scientific reasoning, determine values – surely a good thing to do so. I know about Occam's Razor, but it cuts both ways - solar activity proponents need to show clearly why other influences on climate, especially where the physics and chemistry are not in doubt, ought to be ruled out or downgraded in favour of one that doesn't have much evidence for it except apparent correlation. At best it’s a component, that should be included (if and when there’s anything to pin values to) in the overall science of climate. As you yourself suggested, that since such solar variations are going to be transitory, it may temporarily mask ongoing trends tied to other influences. Given your stated requirement for clear proof, I'm surprise you attribute any validity at all to it.

Now back to Dr Whitehouse - the warming has stopped article has so much wrong with it (as something that informs us about climate science flaws rather than as an attempt to persuade us that we should doubt the science) that I’m not going to bother. If you can’t see it, I must doubt your judgement on what constitutes valid cause for doubting the case for AGW.

lgl said at December 30, 2007 7:29 AM:

How noisy are temperature measurements?
They are very noisy, mainly because of the ENSO: (red is positive enso, blue is negative enso)
Fortunately there is a much better indicator; ocean heat content. Unfortunately there is another "noise" affecting also the heat content, large volcanic eruptions: In addition the measurements are not very reliable. It seeems the XBT gave false readings during the 70's and the ARGOs showed too large decrease after 2003.

All major declines in ocean heat content last 50 years have been caused by very large volcanic eruptions; early 60's, 80's and 90's. So, were there any around 2003? Not exactly, but there were two VEI4 eruptions in late 2002. There have been 6 VEI4 or stronger eruptions since year 2000, between 1994 and 2000 there were none, so it's "very likely" (in IPCC terms :-) that the peak in 2003 was caused by volcanos. Then how do we seperate the signal from the noise? To be able to do that I think the noise must be weaker than the signal, but it isn't.
Here's another interesting page: showing fluxes 10 times the supposed AGW of 1,6 W/m2, i.e they are most likely natural. Note the NET TOA showing a radiation loss after 2002 similar to the one caused by the Pinatubo eruption. This dramatic drop of around 5 W/m2 will probably give more cooling in the years to come. Not to mention after 2010 when the volcanos speed up again, then the AGW-enthusiasts will have hard times.

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