Wednesday, March 22, 2006

Another global warming skeptic bites the dust?

No sooner had I read about this latest alternative theory of global warming, I was able to find an authoritative response. Gotta love the blog world!

The counter theory came from NASA's Earth Observatory site: Greenhouse Theory Smashed by Biggest Stone which lays out a theory by a Russian scientist that a meteor impact perturbed the upper atmosphere, and explains recent warming:

The Tunguska Event, sometimes known as the Tungus Meteorite is thought to have resulted from an asteroid or comet entering the earth’s atmosphere and exploding. The event released as much energy as fifteen one-megaton atomic bombs. Shaidurov suggests that this explosion would have caused "considerable stirring of the high layers of atmosphere and change its structure." Such meteoric disruption was the trigger for the subsequent rise in global temperatures.
With my BS meter instantly twitching, I browsed over the Real Climate blog and quickly found a rebuttal: Meteors, Nuclear Tests and Global Warming
Firstly, one would anticipate that immediate effects of the impact on climate would be strongest near the time of the impact (allowing for some inertia in the system) and decay away subsequently. Secondly, the timescales for any mechanism associated with the impact (in this case disruption of the atmopsheric water vapour) would need to be in line with the change one hopes to explain. And thirdly, one has to show that this explanation is better than the alternatives. Unfortunately, none of of these requirements are met by this hypothesis.
So much for the traditional glacial pace of scientific discovery. Sure these theories and rebuttals have not seen the proper scrutiny yet, and the scientific process will take it's sweet time. But I love the way us spectators can follow the game now.

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