I CRUCIFIED GAIA!:

Not So Dire After All (S. FRED SINGER, February 2, 2007, NY Sun)

The whole question of anthropogenic, or human-caused, global warming is central to setting any policy of climate mitigation and therefore warrants closer examination.

A commonly cited "proof" for human-caused global warming claims there is a scientific consensus. This claim is based mainly on a flawed essay by Naomi Oreskes of the University of California, San Diego, which appeared in the journal Science in December 2004. But even if a majority of scientists had voted for human-caused global warming, that's not how science works. Unlike in politics, the majority does not rule. Rather, every advance in science has come from a minority that found that observed facts contradicted the prevailing hypothesis. Sometimes it took only one scientist; think of Galileo or Einstein.

Another so-called "proof" offered for human-caused global warming is that glaciers are melting and Arctic sea-ice is disappearing. But this is a necessary consequence of warming and says nothing about its cause. Any warming -- whether man-made or natural -- will melt ice. Confusing cause and effect is faulty logic, not proof.

Some cite the fact that the climate is currently warming and the level of carbon dioxide in the atmosphere is increasing. This is true, but correlation is never proof of causation. In Europe, the birth rate is decreasing and so is the number of storks. Does this correlation prove that storks bring babies? Besides, the climate cooled for much of the 20th century, between 1940 and 1975, even while carbon dioxide was increasing rapidly.

Well, what about some 20 greenhouse climate models, all predicting warming -- all the way to 11.5 C from as low as 1.4 C, for a doubling of atmospheric carbon dioxide? Yet no one can tell us which of these models is correct -- if any. And none of these models can explain why the climate cooled between 1940 and 1975 -- without special assumptions. In any case, model results are never evidence. Only actual observations count.

Crucially, greenhouse models cannot explain the observed patterns of warming -- temperature trends at different latitudes and altitudes. These data, published in a U.S. government scientific report in May 2006, lead us to conclude that the human contribution is not significant. Most of current warming must therefore stem from natural causes. It may well be part of an unstoppable solar-driven 1,500-year cycle of warming and cooling that's been documented in ice cores, ocean sediments, stalagmites, and so forth -- going back a million years.

If indeed most of current warming is natural rather than from greenhouse gases, there is little point in reducing carbon-dioxide emissions.

The point is technological innovation and economic efficiency, not environmental effect.

Posted by Orrin Judd at February 2, 2007 12:00 AM