As I noted yesterday, a very important paper (PDF) has just come out on hurricanes and global warming, by Jim Kossin of the University of Wisconsin-Madison's Cooperative Institute for Meteorological Satellite Studies and his colleagues. The paper was published in Geophysical Research Letters. Here's how the University of Wisconsin-Madison's press release describes Kossin's results:
HEADLINE: New evidence that global warming fuels stronger Atlantic hurricanes MADISON -- Atmospheric scientists have uncovered fresh evidence to support the hotly debated theory that global warming has contributed to the emergence of stronger hurricanes in the Atlantic Ocean. The unsettling trend is confined to the Atlantic, however, and does not hold up in any of the world's other oceans, researchers have also found....
Now look at how these same results are described by World Climate Report:
Global hurricane intensity not increasing...so concludes a just-published paper by University of Wisconsin atmospheric scientist Jim Kossin and colleagues. In order that we can't be accused of misrepresenting the authors' meaning, here is the complete conclusion section of their Geophysical Research Letters paper [LONG QUOTATION FROM THE PAPER FOLLOWS] All we can say is "oh my." Can it be possible that the small band of global warming alarmists who is going around pushing the concept that global warming has led to measurably more dangerous hurricanes is wrong? Horrors.
Over at Prometheus, meanwhile, Roger Pielke, Jr., voices his view that the original Wisconsin-Madison press release is guilty of "completely misrepresenting the science in the paper that it is presenting," which has led to some interesting exchanges. Because I discuss this paper in detail in Storm World and don't wish to steal my own thunder, I'm going to remain mostly mum for now about my own view of what's happening here. However, I will make a few fairly obvious points. First, because the new paper's satellite-based reanalysis suggests that hurricane intensity is indeed increasing in the Atlantic but not globally, it's very easy to selectively "frame" this result to support widely disparate interpretations. All you have to do is pick which of these two conclusions to lead with. Second, it's worth recognizing that this is not the first time these results were made public. (I could hardly have covered them in Storm World if they'd only come out just now.) In fact, Kossin gave a talk about his findings back in October (PDF). A key to reconciling the two different "spins" on these findings can be found in his conclusions there:
Similar warming trends are found everywhere in the tropics. Why is the Atlantic behaving so differently? If the data are not good enough to accurately measure long-term hurricane behavior, then our path to understanding how hurricanes will change in a warming world must be through better physical understanding. This is our present research challenge.
In the University of Wisconsin press release, Kossin goes beyond the present paper and tries to do just that--add some "physical understanding":
Sea-surface temperatures may be one reason why greenhouse gases are exacting a unique toll on the Atlantic Ocean, says Kossin. Hurricanes need temperatures of around 27 degrees Celsius (81 degrees Fahrenheit) to gather steam. On average, the Atlantic's surface is slightly colder than that but other oceans, such as the Western Pacific, are naturally much warmer. "The average conditions in the Atlantic at any given time are just on the cusp of what it takes for a hurricane to form," says Kossin. " So it might be that imposing only a small (man-made) change in conditions, creates a much better chance of having a hurricane." The Atlantic is also unique in that all the physical variables that converge to form hurricanes -- including wind speeds, wind directions and temperatures -- mysteriously feed off each other in ways that only make conditions more ripe for a storm. But scientists don't really understand why, Kossin adds.
Now, Prometheus is right to observe that this kind of stuff is not in Kossin's latest paper. But I suspect that it may be found in other work of his, such as this paper listed on Kossin's website: "Kossin, J. P., and D. J. Vimont, 2007: A more general framework for understanding Atlantic hurricane variability and trends. Bull. Amer. Meteor. Soc., in review." In any event, I'll leave you with this question: Is it really wrong for a press release to go beyond a single study to provided a broader interpretation of that study's results? Don't we want scientists to contextualize their findings?
P.S.: Left this additional comment at Prometheus:
It seems to me that one issue raised by Roger's post is whether it's appropriate for a press release to go beyond the findings of the latest study so as to provide a broader context for interpreting those findings, perhaps drawing upon other research to do so. Press releases would be sterile indeed if they had to be purely technocratic recaps of the latest findings, and nothing more.
P.P.S.: Real Climate has now done a post and opened a thread on the Kossin study. I'm sure there will be much more valuable commentary over there, so for anyone who wants more depth.....
UPDATE: Indeed, Jim Kossin, Kevin Trenberth, and Judith Curry are discussing the paper over at RealClimate now, so while this thread provides some good one-stop shopping about press releases and spin, and Prometheus provides more, that's where the scientific dialogue is now happening. I might add that this is a real achievement on RealClimate's part...a few years ago most scientists wouldn't have been caught dead on the blogs. Now, it's almost routine for them to comment there.