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Behind predictions of catastrophic global temperature increases are climate models specified and estimated by atmospheric and other physical scientists. Such models generally predict that doubling atmospheric carbon dioxide would produce warming of 3C to 4C (although some predict as high as 11C). Generating estimates based on doubling carbon dioxide is accepted convention for assessing the climate sensitivity of the models.
When climate models employed to forecast the future are used with historical data, however, they fare very poorly. Applying historical data to predictive models is a common procedure in physical and social sciences. If a model cannot account for past experience, then its value for forecasting the future is cast into doubt—or so one might think.
Not so in climate science, however. Model-generated estimates of past atmospheric temperatures enormously exceed what has actually been observed. So, the models contain significant specification errors, and scientists know this. “Thus”, writes Richard S. Lindzen, Alfred P. Sloan Professor of Atmospheric Sciences, Massachusetts Institute of Technology, “the real situation is that the supporters of alarm are the real skeptics who cling to alarm against widely accepted findings.”
Most current climate models predict a response to a doubling of CO2 of about 4C. The reason for this is that in these models, the most important greenhouse substances, water vapor and clouds, act in such a way as to greatly amplify the response to anthropogenic greenhouse gases alone (ie, they act as what are called large positive feedbacks). However, as all assessments of the Intergovernmental Panel on Climate Change (IPCC) have stated (at least in the text – though not in the Summaries for Policymakers), the models simply fail to get clouds and water vapor right. We know this because in official model intercomparisons, all models fail miserably to replicate observed distributions of cloud cover . . . Thus, the model predictions are critically dependent on features that we know must be wrong.
Predictions based on these models are greatly in excess of what has been observed. Thus, if predictions based on these models are correct (after all stopped watches are right twice a day), then man’s greenhouse emissions have accounted for about 6 times the observed warming over the past century with some unknown processes canceling the difference. [Emphasis added.]
I was astonished to realise this. In my time as graduate student in economics, I attended many seminars at which students and faculty presented research in progress. If anyone had brought a model suggesting some immense change in future economic conditions, while the same model failed to account for recent economic history, it would have been sent back to the drawing board. I cannot imagine that such a model would have been taken seriously, much less accepted as a solid basis for discussion of public policy.
Yet, according to Dr Lindzen, precisely that is happening in climate science—not just in one or two eccentric university departments, but throughout the Western world. Models that scientists know are erroneous in essential aspects are being used to justify public policies that potentially entail the expenditure of billions of dollars for decades to come by nations around the world.
Moreover, the quantity of greenhouse gases (GHG) added to the atmosphere by human activity since the late 19th century has already produced over 72% of the gross radiative forcing expected from doubling of carbon dioxide. Yet the global temperature has increased by only 0.6C in the past century. This is further evidence that climate change models are grossly overestimating the effect of GHG emissions, and is consistent with and corroborative of independently identified negative feedback processes.
In fact, observed temperature change is so small that Dr Lindzen considers it impossible to distinguish from natural variation.
The claim that global warming alarmism represents a “consensus” of scientific views is an egregious oversimplification, if not misrepresentation, of the state of scientific opinion. There is, however, clear consensus among experts in the relevant sciences that full and complete implementation of the Kyoto Protocol would have no discernable impact on climate.
A question rarely asked, but nonetheless important, is whether the promotion of alarmism is really good for science? The situation may not be so remote from the impact of Lysenkoism on Soviet genetics. However, personally, I think the future will view the response of contemporary society to ‘global warming’ as simply another example of the appropriateness of the fable of the Emperor’s New Clothes. For the sake of the science, I hope that future arrives soon.
Global warming alarmism analogous to Lysenkoism? Emperor's New Clothes? That’s gotta hurt. Al Gore, are you paying attention? (If the past is any guide, probably not.)
Read the whole thing (pdf format).
via titusonenine.
Crosswalk.com link via commenter Jim the Puritan at titusonenine.
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