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No Hot Air

“Theory and modeling predict that hurricane intensity should increase with increasing global mean temperatures, but work on the detection of trends in hurricane activity has focused mostly on their frequency and show no trend.

“Theory and modeling predict that hurricane intensity should increase with increasing global mean temperatures, but work on the detection of trends in hurricane activity has focused mostly on their frequency and show no trend. Here I define an index of the potential destructiveness of hurricanes based on the total dissipation of power, integrated over the lifetime of the cyclone, and show that this index has increased markedly since the mid-1970s. This trend is due to both longer storm lifetimes and greater storm intensities. I find that the record of net hurricane power dissipation is highly correlated with tropical sea surface temperature, reflecting well-documented climate signals, including multidecadal oscillations in the North Atlantic and North Pacific,” writes MIT professor of atmospheric science Kerry Emanuel in the opening to a piece that appears in the August 2005 issue of Nature (ftp://texmex.mit.edu/pub/emanuel/PAPERS/NATURE03906.pdf). Written pre-Katrina, it basically says that hurricanes are getting more horrendous—although he uses math and data to make that point, not an adjective. There are actually three other words that should be attachment to the final sentence in that quote, three words that will have some people nodding their heads approvingly and others rolling their eyes exasperatedly: “. . .and global warming.”

Yes, Emanuel, who studies climatic conditions, thinks that there is climatic change occurring. And he’s written a short book on the subject that is far more straightforward than those quoted passages above might lead you to think. Unlike many people weighing in on the subject, Emanuel admits that there is plenty we don’t know. He admits that there are “uncertainties” and points out, “to understand long-term climate change, it is essential to appreciate that detailed forecasts cannot, even in principle, be made beyond a few weeks. That is because the climate system, at least on short time scales, is chaotic. The essential property of chaotic systems is that small differences tend to magnify rapidly.” So it is hard to make hard-and-fast claims. But here’s an important point: “In pushing the climate so hard and so fast, we are also conscious of our own collective ignorance of how the climate system works. Perhaps negative-feedback mechanisms that we have not contemplated or have underestimated will kick in, sparing us from debilitating consequence. On the other hand, the same could be said of positive feedbacks, and matters might turn out worse than projected.” We just don’t know. And he points out that while he and some of his colleagues in the scientific community cannot say with certainty whether the ice caps are going to melt anytime soon, there are some who are hyping the issue with extreme hot air: “Ever eager for the drama of competing dogmas, the media largely ignored mainstream scientists, whose hesitations did not make good copy. As the global-warming signal continues to emerge, this soap opera is kept alive by a dwindling number of deniers constantly tapped for journalists who pretend to look for balance.”

Evidence notwithstanding, one might consider a version of Pascal’s wager when it comes to the issue of global warming: Blaise Pascal had posited that it is better to believe in God than not because if God exists, you’re in good shape for believing, and if you don’t . . . Similarly, if global warming exists, then making efforts to reduce greenhouse gases are better than not.

And even for those who continue to be skeptical, this passage strikes me as one that ought to make them reconsider the position of U.S. industry on the subject: “The United States is renowned for its technological innovation and should be at an advantage in making money from any global sea change in energy-producing technology: consider the prospect of selling new means of powering vehicles and electrical generation to China’s rapidly expanding economy.” In other words, there are people who believe that the status quo isn’t right, and they are willing to pay for alternative technologies. However, the sentence that follows that quote: “But none of this has happened.” To be sure, there are efforts being made by, say, General Motors, but when it comes to salable hybrid vehicles, there were 137,114 Priuses sold through September 2007, which is nothing to sniff at.—GSV