The report from the National Academy of Sciences was not the only climate study released today. A pair of scientists at the National Center for Atmospheric Research released a study — to be published in the coming issue of Geophysical Research Letters — that purports to show that the majority of the warming of ocean waters that led to the horrendous hurricane season of 2005 is attributable to global warming.
Sea-surface temperatures in the tropical Atlantic in 2005 were an average of 1.7 degrees Fahrenheit warmer than the 1900-1970 average:
Their calculations show that global warming explained about 0.8 degrees F of this rise. Aftereffects from the 2004-05 El Nino accounted for about 0.4 degrees F. The Atlantic multidecadal oscillation (AMO), a 60-to-80-year natural cycle in SSTs, explained less than 0.2 degrees F of the rise, according to Trenberth. The remainder is due to year-to-year variability in temperatures.
This, needless to say, strongly contradicts the common claim that the AMO is responsible for most of the rise in hurricane activity over the last decade. I don’t know anything about these two guys — Kevin Trenberth and Dennis Shea — or their reputations, and of course I have no way of knowing how these results will hold up over time, but at the very least it’s a provocative finding in an area of science and culture that is fiercely contested.
For that reason I’m somewhat surprised that the study hasn’t gotten more attention relative to the NAS report (which, after all, just confirmed conventional wisdom). ThinkProgress flagged it and it got mentions here, here, and here, but it’s received nothing close to the mainstream press coverage.
Even if the study holds up, it doesn’t mean global warming is "half to blame" for a given hurricane, and it certainly doesn’t mean that global warming is responsible for half the damages caused by a particular hurricane. But it does put a solid foundation under the galvanizing claim that global warming is going to lead to more vicious storms — not a pleasant prospect.