Monday, July 30, 2007

In the eye of the storm

Storm World: Hurricanes, Politics, and the Battle Over Global Warming
by Chris Mooney
Harcourt: July 2007. 392 pp. $26

[An edited version published in Nature, v448, 648, August 9, 2007]

Chris Mooney’s follow-up to his The Republican War on Science (Basic Books, 2005) is a reconnaissance flight into the turbulent debate on a possible link between hurricane activity and global warming. The flight log is compelling enough for Hollywood. It records a clash between the empiricist climate scientist William Gray (think Ian McKellen) at Colorado State University (in a red state) and the theoretician Kerry Emanuel (think Tom Hanks) at the Massachusetts Institute of Technology (in a blue state). Journalist Mooney has a scriptwriter’s flair for pitting his protagonists against each other and dishing the historical and methodological back story in vivid prose: “If we’re really making the deadliest storms on Earth still deadlier, it will represent one of humanity’s all-time greatest foot-shooting episodes.”

The debate swirls about the cause of the recent upswing in severe hurricanes, especially over the Atlantic where evidence for a change is most compelling (here). There is no question that warmer tropical oceans will increase the potential intensity of tropical cyclones (all else being equal), but for Gray the causal chain ends with the ocean. “Nobody knows how the atmosphere works,” he says, feeling that it is far too complicated to be captured by a computer. Emanuel, on the other hand, adds a further link to the chain, placing the blame on human meddling with the composition of the atmosphere (aerosols and greenhouse gases). Having challenged Gray and his colleagues on their forecast methods, it's clear why it took someone with Emanuel's stature (Time Magazine) to spar with him on the climate-change issue.

Just a month before hurricane Katrina’s devastating strike on America’s south coast on 29 August 2005, Emanuel published a paper in this journal (Nature 436, 686–688; 2005) that ignited a scientific debate by linking storm strength to ocean temperatures. It also triggered a maelstrom of media coverage that resulted in the US National Oceanic and Atmospheric Administration (NOAA) closing ranks and claiming unequivocally that the increase in Atlantic hurricane activity since 1995 could be attributed solely to an ocean cycle unrelated to greenhouse warming. Mooney is at his best when describing the political tempest. By allowing what Emanuel calls the “party line” while discouraging dissenters, NOAA was, in Mooney’s words, “gaming the release of information and trying to shift the debate in their favored direction.”

Mooney revisits his call, propounded in his earlier book and in subsequent newspaper columns, for scientists to do a better job of communicating science to the public and media. He urges researchers to stop pretending that they are nothing but objective “fact machines” and to instead give more general interpretations of their results and put them into a broader context.

Drawing on scientific conferences and on interviews with hurricane and climate scientists during 2006, Mooney covers plenty of ground, from heat engines and synoptic meteorology to computer modeling, and all without equations. At times it feels hurried, US-centric and somewhat uneven, jumping between history, science and politics. But Mooney presents an accurate account of the clash between two of the most prominent climate scientists today. He is a good writer — “Scientists, like hurricanes, do extraordinary things at high wind speeds” — and his stories are consistently about people, giving the book a wide appeal.

In the end he gives us a clear picture of what the hurricane–climate change debate is about and where it might go next (sensitivity). As there are no answers, Mooney provides none. Not surprisingly, Chris takes a liking to Bill, but cannot recommend his view that global warming has nothing to do with hurricane activity. I also detected a commentary about storm climatologists for which science sometimes plays second fiddle to entertaining sound bites.

While the inner-core dynamics are well resolved in Storm World, a hurricane needs its outer rain bands and there are many scientists contributing to the whirlwind surrounding what is arguably the most important climate debate in history. Neither side is completely wrong and both would do well to study the full breadth of literature.

Storm World is a great summer read. The story continues however with more answers likely in the sequel.