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11 November 2011: Matt Ridley, renowned British author, recently delivered the Angus Millar Lecture of the Royal Society of the Arts in Edinburgh. The subject of his speech was scientific heresy and the "pseudoscience" of climate change, as he calls it. Matt is a self-described "lukewarmer," accepting that CO2 is a greenhouse gas, that the climate has been warming, and that man is at least partly responsible.
Matt succinctly summarizes the bankruptcy of the theory of man-made global warming:
"...there is no evidence that climate is changing dangerously or faster than in the past, when it changed naturally. It was warmer in the Middle Ages and medieval climate change in Greenland was much faster.
Stalagmites, tree lines and ice cores all confirm that it was significantly warmer 7000 years ago. Evidence from Greenland suggests that the Arctic ocean was probably ice free for part of the late summer at that time. Sea level is rising at the unthreatening rate about a foot per century and decelerating. Greenland is losing ice at the rate of about 150 gigatonnes a year, which is 0.6% per century. There has been no significant warming in Antarctica, with the exception of the peninsula. Methane has largely stopped increasing. Tropical storm intensity and frequency have gone down, not up, in the last 20 years. Your probability of dying as a result of a drought, a flood or a storm is 98% lower globally than it was in the 1920s. Malaria has retreated not expanded as the world has warmed.
And so on. I've looked and looked but I cannot find one piece of data - as opposed to a model - that shows either unprecedented change or change is that is anywhere close to causing real harm."
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Ridley attacks the heart of the issue with a discussion about climate sensitivity. Climate sensitivity is usually defined as the amount the Earth will warm from a doubling in atmospheric carbon dioxide levels. Climate sensitivity includes not only the affects of CO2 increase, but also the additional warming or cooling from other forces as Earth reacts to the doubling of CO2.
Ridley points out that climate scientists generally agree that the warming from a doubling of CO2 alone would warm global temperatures about 1.2 degree C. This rise by itself is not enough to cause the catastrophic impacts projected by many global warming doomsayers. The big disagreement is in the size of the feedback, that is, how Earth reacts to the doubling. The Global Circulation Models on which the Intergovernmental Panel on Climate Change rely all conclude that a positive feedback will be added to CO2 rise, boosting global temperatures from 1.2 degrees C to an average of 3 degrees C.
But, our modern rise in global temperatures does not support model predictions. As the graph to the right shows, surface temperatures have risen about 0.6-0.7 degrees C in the last 150 years as atmospheric CO2 levels have risen from a pre-industrial level of about 285 ppm to today's level of 390 ppm.
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 Click on image above to see a larger view of this graph. |
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If the entire temperature rise is assumed to be due to CO2 and not natural climatic cycles, then the Earth's temperature is rising along the 1.2 degrees C per doubling curve, not the 3 degrees C per doubling curve called for by the models. This is yet another indication that the models are overstating climate sensitivity.
See the rest of Ridley's speech here.
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