Editor's Note: reason Science Correspondent Ronald Bailey will be filing a series of regular dispatches from the Heartland Institute's controversial International Conference on Climate Change. Below is the final dispatch in that series.
New York, March 4—Let's start with some possible news from Heartland Institute's International Climate Change Conference. In the context of man-made global warming, climate sensitivity asks how much temperatures increase if one adds a specified amount of a greenhouse gas. In general, most climatologists accept the proposition, all things being equal, that if one doubles carbon dioxide in the atmosphere the average temperature will go up by +1 degree centigrade. But all things are not equal. In climate models, additional heat from carbon dioxide boosts atmospheric water vapor which in turn acts as a greenhouse gas. All models are dominated by this positive feedback loop. As a consequence, the U.N.'s Intergovernmental Panel on Climate Change (IPCC) estimated in its Fourth Assessment Report (4AR) last year that it "is likely to be in the range 2 to 4.5°C with a best estimate of about 3°C, and is very unlikely to be less than 1.5°C." In other words, doubling carbon dioxide in the atmosphere is likely to warm the planet by between 2 degrees and 4.5 degrees centigrade.
So how do we find out how sensitive climate is to CO2? During his luncheon keynote, University of Alabama climatologist Roy Spencer described how two of his new studies are attempting to answer that question. In 2001, Massachusetts Institute of Technology climatologist Richard Lindzen hypothesized that there might be what he called an "adaptive infrared iris" over the tropics through which tropical storms dissipate excess heat. But other researchers looked and found no strong evidence for such a mechanism.
Now Spencer and his colleagues using satellite data noticed big temperature fluctuations in the tropics in which strong warming was followed by rapid cooling. So Spencer looked at 15 strong intraseasonal oscillations in the tropics to see how clouds evolve. What was known is that tropical storms produce high cirrus clouds. Cirrus clouds are global warming culprits that retain heat and warm the planet. In the climate models, cirrus clouds tend to remain aloft for a long time. However, Spencer's satellite observations found that they in fact dissipate rapidly, allowing heat to escape back into space and thus cooling the planet.
"To give an idea of how strong this enhanced cooling mechanism is, if it was operating on global warming, it would reduce estimates of future warming by over 75 percent," Spencer noted when the study was published in Geophysical Research Letters. "The big question that no one can answer right now is whether this enhanced cooling mechanism applies to global warming." Clouds constitute the biggest uncertainty in climate models and Spencer is hoping the modelers will include this effect in future runs to see how it would affect climate projections.
Next, Spencer discussed new research (accepted but not yet published) that he said strongly suggests that climate sensitivity is much lower than the climate models find. As I understood Spencer (and I could be garbling this), in the climate models a feedback is by definition a result of surface temperature change.
As Spencer explained his preliminary thinking at the website Climate Science, "For instance, low cloud cover decreasing with surface warming would be a positive feedback on the temperature change by letting more shortwave solar radiation in. But what never seems to be addressed is the question: What caused the temperature change in the first place? How do we know that the low cloud cover decreased as a response to the surface warming, rather than the other way around?"
In fact, using satellite data combined with a small model, Spencer finds that changes in cloudiness appear to drive changes in temperature. If this is so, Spencer suggests, this means that models have fundamentally mixed up cause and effect. He reported that his study had been peer-reviewed by the two of the climatologists on whose work the IPCC relied for estimating climate sensitivity. "Both came back and said 'you're right,'" claimed Spencer.
If Spencer's results are confirmed—and this is a huge if—it would mean that the climate is far less sensitive to perturbation by carbon dioxide than the models suggest. Spencer says that if he is right about climate sensitivity that would imply that the average temperature of the planet might rise by +0.5 degrees centigrade by the end of this century due to the effects of rising carbon dioxide concentration in the atmosphere. (I will report more fully on Spencer's claims once the study is published and the climatological community has gotten a chance to respond to it).
But let's go back to politics. The final morning of the conference began with a rousing speech by Vaclav Klaus, the president of the Czech Republic. He made it clear that to call him a global warming skeptic would be a bit of an understatement. A point Klaus makes crystal clear in his just published book, Blue Planet in Green Chains - What is Endangered: Climate or Freedom? "My answer is clear and resolute: 'it is our freedom.' I may also add 'and our prosperity,'" declared Klaus.
Klaus noted that ideological environmentalism appeals to the same sort of people who have always been attracted to collectivist ideas. He warned that environmentalism at its worst is just the latest dogma to claim that a looming "crisis" requires people to sacrifice their prosperity and their freedoms for the greater good. Let me quote Klaus at length.
"Future dangers will not come from the same source. The ideology will be different. Its essence will, nevertheless, be identical—the attractive, pathetic, at first sight noble idea that transcends the individual in the name of the common good, and the enormous self-confidence on the side of its proponents about their right to sacrifice man and his freedom in order to make this idea reality," warned Klaus. "What I have in mind [is], of course, environmentalism and its currently strongest version, climate alarmism."
Klaus added, "What I see in Europe (and in the U.S. and other countries as well) is a powerful combination of irresponsibility, of wishful thinking, of implicit believing in some form of Malthusianism, of cynical approach of those who themselves are sufficiently well-off, together with the strong belief in the possibility of changing the economic nature of things through a radical political project."
But assume that man-made global warming is a genuine crisis. That it is a real gigantic open access commons problem. Wouldn't that require some kind of governmental action to coordinate a solution to the problem? I have recently come out in favor of using a carbon tax as a way to spur the technological innovation toward a low-carbon energy economy (and incidentally as a way to also reduce taxes on labor and capital). This was not a popular position at the conference. Why not?
While many environmentalists focus on mitigation (cutting greenhouse gas emissions), many of the economists who spoke at the conference argued that adaptation through wealth creation is the better strategy. Policies aimed at reducing energy consumption to mitigate man-made global warming would likely result in a poorer, less technologically adept future in which future generations would be less able to address the problems caused by climate change. This is clearly true and as a reluctant proponent of a carbon tax, I am painfully aware of this trade-off.