Two Sides to Global Warming

Is it proven fact, or just conventional wisdom?

Ronald Bailey | November 10, 2004

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But the average temperatures for most of Antarctica outside of the Antarctic Peninsula have been declining since the mid-1960s. So is this evidence that the amount of warming predicted by computer climate models is wrong? Not so fast, say even some climatologists who report on the Antarctic cooling. They insist that their data do not overturn predictions of rapid global warming. Richard Lindzen, a climatologist from MIT and a global warming skeptic, points out, "the Antarctic is not warming and there is nothing in the models that distinguish the temperature trends they predict in the Arctic from those in the Antarctic." Climate is messy.

With so many researchers in the climatological community apparently convinced of the reality of dangerously rapid man-made climate change, why do I continue to rely so much on the skeptical Christy? Christy is the climatologist who has put together the highly accurate atmospheric temperature data from satellites since 1978. And confidence in his data is bolstered by the fact that they correlate nicely with temperature data from radiosondes, which are a completely independent measure of temperature. Christy's data show that since 1978 the planet is warming up at a rate of 0.08 degrees Celsius per decade. The Arctic, according to Christy's data, is indeed warming faster than the rest of the planet, at a rate of 0.39 per decade. But the Antarctic is cooling by 0.12 degrees Celsius per decade.

For the nationalistic, Christy's satellite data find that the lower 48 states of the U.S. are warming at a rate of 0.07 degrees per decade. If temperatures continue to increase by 0.08 degrees Celsius per decade, the planet will warm by 0.8 degrees Celsius by the end of the century. That compares to an increase of 0.6 degrees Celsius during the 20th century. Not much of a crisis. Richard Lindzen says he's willing to take bets that global average temperatures in 20 years will in fact be lower than they are now.

So is dangerous rapid global warming merely the new conventional wisdom—or a credible forecast of our climatic future? There's plenty of evidence for both positions, and I'll keep reporting the data and the controversy.