Monday, February 15, 2010

Kerry Emanuel: Basic Knowledge missing?

Is his true?

And fourth, global temperatures have been rising for roughly the past century and have so far increased by about 1.4 F. The rate of rise of surface temperature is consistent with predictions of human-caused global warming that date back to the 19th century and is larger than any natural change we have been able to discern for at least the past 1,000 years.

I mean especially the bold part of the phrase. It is directly from an opinion piece to the Boston Globe by Kerry Emanuel (MIT).

Either his experience in the debate is truly limited, in which case he is badly informed. Or he is ignorant to some of the most important graphs in temperature history, especially since he invokes the 1000 year mark. Not only has the NAS panel limited certainty for temperatures as far in the past as 1000 years, but there are also warming periods in the medieval era, which are comparable in magnitude to the warming since 1900.

So, as an opinion piece of an expert, I find it somehow lacking on detail knowledge. Natural cycles are known to have a 0.2°C rise per decade in average surface temperature, which, if you multiply it by 10 decades per century, gives you a 2° C rise in temperature. This then is approx. the 1.4 °C rise in temperature we have observed in the last century.

We were recovering from a little Ice Age during the 1600-1700 and thus a rise was essentially natural. IF now the rise had been augmented due to CO2, we would surely have had even higher temperatures. We don’t, which should lead to the conclusion that albeit CO2 may play a role, it is greatly exaggerated at least in the last 100 years.

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