A case against climate alarmism...

Richard Lindzen of MIT is one of my favorite scientists....

Climate is always changing. We have had ice ages and warmer periods when alligators were found in Spitzbergen. Ice ages have occurred in a hundred thousand year cycle for the last 700 thousand years, and previous warm periods appear to have been warmer than the present despite CO2 levels being lower than they are now. More recently, we have had the medieval warm period and the little ice age. During the latter, alpine glaciers advanced to the chagrin of overrun villages.

Since the beginning of the 19th Century these glaciers have been retreating. Frankly, we don't fully understand either the advance or the retreat. For small changes in climate associated with tenths of a degree, there is no need for any external cause. The earth is never exactly in equilibrium. The motions of the massive oceans where heat is moved between deep layers and the surface provides variability on time scales from years to centuries. Recent work (Tsonis et al, 2007), suggests that this variability is enough to account for all climate change since the 19th Century. Supporting the notion that man has not been the cause of this unexceptional change in temperature is the fact that there is a distinct signature to greenhouse warming: surface warming should be accompanied by warming in the tropics around an altitude of about 9km that is about 2.5 times greater than at the surface.

Measurements show that warming at these levels is only about 3/4 of what is seen at the surface, implying that only about a third of the surface warming is associated with the greenhouse effect, and, quite possibly, not all of even this really small warming is due to man. This further implies that all models predicting significant warming are greatly overestimating warming. This should not be surprising. According to the UN's Intergovernmental Panel on Climate Change, the greenhouse forcing from man made greenhouse gases is already about 86 % of what one expects from a doubling of CO2 (with about half coming from methane, nitrous oxide, freons and ozone), and alarming predictions depend on models for which the sensitivity to a doubling for CO2 is greater than 2C which implies that we should already have seen much more warming than we have seen thus far, even if all the warming we have seen so far were due to man.

This contradiction is rendered more acute by the fact that there has been no significant global warming for the last ten years. Modelers defend this situation by arguing that aerosols have cancelled much of the warming, and that models adequately account for natural unforced internal variability. However, a recent paper (Ramanathan, 2007) points out that aerosols can warm as well as cool, while scientists at the UK's Hadley Centre for Climate Research recently noted that their model did not appropriately deal with natural internal variability thus demolishing the basis for the IPCC's iconic attribution. Interestingly (though not unexpectedly), the British paper did not stress this. Rather, they speculated that natural internal variability might step aside in 2009, allowing warming to resume. Resume? Thus, the fact that warming has ceased for the past decade is acknowledged.