By Tom Still
MADISON – The destruction of New Orleans and Biloxi by Hurricane Katrina has released another type of storm among scientists who wonder if “global warming” is making deadly weather even deadlier. The debate won’t help last week’s victims along the Gulf Coast, but it could better prepare us for tomorrow’s hurricanes.
About a month before Katrina turned New Orleans into a watery ghost town, a climate researcher at the Massachusetts Institute of Technology published a paper in the online version of “Nature” that intrigued global warming buffs. It concluded the destructive power of hurricanes in the North Atlantic and North Pacific has nearly doubled over the past 30 years, at least partly because of human-induced climate change.
Everyone agrees the number of tropical cyclones (a catch-all term for hurricanes and typhoons) has stayed around 90 per year for decades, but MIT researcher Kerry Emanuel said those storms are getting larger and reaching higher maximum wind speeds than storms in the past. “There seems to be a clear correlation,” Emanuel said, between stronger storms and a temperature increase of 0.5 degrees Celsius on the surface of the sea during the same period.
Not so fast, said a leading hurricane forecaster. William Gray of Colorado State University said Emanuel leapt to conclusions based on imprecise information about hurricane strength, especially in decades past. He said Emanuel’s formula for calculating the energy released by hurricanes overlooks the fact that no one directly measured the winds in many of the storms. Instead, speeds were roughly estimated from satellite images.
“It’s a terrible paper, one of the worst I’ve ever looked at,” grumbled Gray, who doubts storm intensity has increased. He also questions whether human actions, such as the burning of fossil fuels, have anything to do with it what could be a natural warming of the oceans.
Gray’s condemnation of Emanuel’s research may seem harsh, but it illustrates the depth of disagreement among climate scientists. In late July, Roger Pielke Jr. of the University of Colorado posted a paper in the Bulletin of the American Meteorological Society, in which he concluded there was little, if any, evidence of global warming in hurricane patterns. That so irked Kevin Trenberth of the National Center for Atmospheric Research that he called Pielke’s paper “a shameful article.”
Six months before that incident, respected hurricane scientist Christopher Landsea of the National Hurricane Research Laboratory quit the United Nations’ Intergovernmental Panel on Climate Change. He was upset that Rajenda Pauchari, director of the U.N. panel, had condoned Trenberth’s statements that hurricanes were worsening because of global warming.
Writing in August for the libertarian Cato Institute, author and policy analyst Patrick J. Michaels blamed “the especially shoddy nature of the current scientific review process on global warming papers.” If hurricanes had actually doubled in power in the last few decades, Michaels observed, the inflation-adjusted economic losses from those hurricanes would have climbed just as dramatically. Instead, the growth in hurricane damage mirrors the unrelenting rise in shoreline development.
“Hurricanes are causing greater dollar damages because more and more people are building increasingly expensive beachfront monstrosities that have financially appreciated during the recent real-estate bubble. Account for these and there is no significant change in hurricane expenses along our coasts,” Michaels wrote.
That brings us back to New Orleans, a city that was reclaimed in part from swamps and lowlands that still want to be swamps and lowlands. While U.S. House Speaker Dennis Hastert, R-Ill., didn’t score style points when he said much of New Orleans resembled bulldozer fodder, it makes sense to think about which sections should be rebuilt and which should revert to serving as buffer and flood zones.
Hurricane Katrina was cruelly powerful, but let’s not prematurely conclude she became so by feasting off waters warmed by our car engines. Let’s focus instead on restoring natural shoreline areas and getting a lot smarter about where we build.