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Correction of Errors in Fortune Story

Post co-authored by Roger Pielke, Jr. (RP) and Kerry Emanuel (KE)
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Over this past week as the horrific disaster along the Gulf coast has developed in the aftermath of Hurricane Katrina, we have both been quoted extensively in the media based on our various work on hurricanes. For the most part the reporting of our views has been accurate and responsible. With this short post, we'd like to correct some significant mischaracterizations and errors in a Fortune news story. We address them below.

1. The Fortune story states, "But Emanuel and other experts have warned for over a decade that global warming may be creating an environment prone to more violent storms, droughts and other weather extremes ... " This may be true of "other experts" but it is not an accurate characterization of KE's statements over the past decade.

2. The Fortune story states, "A forthcoming paper co-authored by University of Colorado researcher Roger Pielke Jr. argues that by 2050, hurricane losses due to both coastal population growth and the rising value of coastal property will be 22 to 60 times greater than those that are potentially caused by global warming's effects. Ironically, MIT's Professor Emanuel was a co-author of that paper. But after compiling the startling data on intensifying hurricanes, he says, "I changed my mind" and struck his name from the authors' list."

The reason that KE decided to withdraw amicably from co-authorship had nothing to do with the paper's summary of research on the societal impacts of hurricanes, as implied here, but instead, a change in KE's views on the significance of global warming in observed and projected hurricane behavior. It is misleading to use KE's withdraw to dismiss the entire paper. Here is how KE characterized his withdrawal to RP in an email:

"The awkward situation we find ourselves in is bound to occur when research is in rapid flux. Working with both data and models, I see a large global warming signal in hurricanes. But it remains for me to persuade you and other of my colleagues of this, and it is entirely reasonable for you all to be skeptical...it is, after all, very new. It is not surprising, therefore, that what I have come to believe is at odds with any reasonable consensus. The problem for me is that I cannot sign on to a paper which makes statements I no longer believe are true, even though the consensus is comfortable with them."

We remain close, collegial colleagues who are seeking to advance science by challenging each others ideas in the traditional fora of scientific discourse. We hope that the media will recognize that science is complex and legitimate, differing perspectives often co-exist simultaneously. This diversity of perspective is one feature that motivates the advancement of knowledge.

3. The Fortune story states, "Emanuel found that since 1949, the average peak wind speeds of hurricanes over the North Atlantic and the western and eastern North Pacific has increased by a whopping 50%... Meanwhile the duration of the storms, in terms of the total number of days they lasted on an annual basis, rose by roughly 60%." This is a mischaracterization of the recent research conducted by KE, which instead found an increase in the power dissipation of hurricanes, an integrated measure of peak wind speeds and storm duration; it is the cube of the wind speed that has increased by about 50%, not the wind speed itself.

4. Finally, the story misuses the term "hypercanes" which refers to theoretical research conducted by KE and colleagues in the mid-1990s. The term has nothing to do with the present or near-term future. Hypercanes require ocean temperatures of at least 50 C and may have formed shortly after collisions of large extraterrestrial bodies, such as asteroids, with the earth; they will not arise as a consequence of global warming.