Thursday, September 8

storms over storms

In the wake of Hurricane Katrina, people are wondering what scientists knew beforehand and what they could have done--both in this particular case and in general. A couple fascinating articles on this have come out in the last two days.

A story in the Chronicle of Higher Education addresses the long-standing debate over whether the world is getting stormier, and if so, whether global warming is to blame. The article focuses on the work of one climate scientist who recently changed his mind on the subject:
When it came to global warming and hurricanes, Kerry A. Emanuel used to be a skeptic. In fact, as one of the foremost theorists who studies such storms, Mr. Emanuel helped write a paper last year dismissing the idea that climate change would make hurricanes significantly more dangerous.

That paper will soon be published in a meteorological journal. But Mr. Emanuel's name will not be on it.

While looking at historical records, the atmospheric physicist at the Massachusetts Institute of Technology found that the total power released by storms had drastically increased -- more than doubling in the Atlantic Ocean in the past 30 years. The evidence was so overwhelming that he could not stand by his earlier statements. (Link to story.)

Emanuel published last month in the journal Nature in which he used a new measure of hurricanes to estimate the total amount of energy they dish out. From the abstract of his paper:
Theory and modelling predict that hurricane intensity should increase with increasing global mean temperatures, but work on the detection of trends in hurricane activity has focused mostly on their frequency and shows no trend. Here I define an index of the potential destructiveness of hurricanes based on the total dissipation of power, integrated over the lifetime of the cyclone, and show that this index has increased markedly since the mid-1970s.

Nature also had a news story yesterday about what scientists knew about the risk New Orleans was under, and whether researchers could have done more to influence policy. The story is available only by subscription, so I quote at length:
Nothing about last week's hurricane and the subsequent flooding of New Orleans should have come as a surprise. Experts knew such a storm would come at some point. They knew the coast's natural defences were degraded; they knew the levees were not designed for anything stronger than a category-3 storm; and they knew that a significant proportion of the population - the poorest and weakest - would not evacuate.

The science was all there, but apparently the planning was not....

It has also long been known that the system of raised levees and floodwalls that keep New Orleans dry are only designed to withstand hurricanes up to category 3. A project looking at upgrading the system is in the works, but after five years it is still in the pre-study phase. To be ready for Katrina, "we would have had to start working on category-5 twenty years ago", says Alfred Naomi, a senior project manager for the Army Corps of Engineers, which maintains the levee system....

Days ahead of the storm's arrival, computer simulations of the expected surge showed that water would probably overflow levees, flooding the city, which lies below sea level.

"It's a valuable tool," Luettich says. "Where we've had less success is in getting people to take it seriously and modify their behaviour based on it."...

Others say scientists should take part of the responsibility. "Folks have talked about this scenario for decades, yet I've watched George Bush senior and Bill Clinton both comment that no one could have anticipated this sort of event," says Roger Pielke, director of the Center for Science and Technology Policy Research at the University of Colorado, Boulder. "That raises some real questions for the academic and scholarly community. What does it mean if scholars are aware of something with practical importance, but it doesn't get to the people who can take action?"

Pielke argues that scientists need to move away from a 'loading dock' approach where they simply put out raw information for anyone who wants to use it. Instead they should tailor their research to practical needs, he says. "There's a real challenge of making knowledge useful. It is not something that the academic community is engaged in as a matter of policy."

Science journalists traditionally have had the job of trying to make relevant research findings accessible to people so they can actually use them. I'm not sure science journalists did a good job in this regard. I had heard the idea that New Orleans could be screwed if a big storm came; the city has been fighting against the river for decades. But did I think to write an article about it? No.

Here's one news story from Nature from before the storm, on how a scientist quit the influential Intergovernmental Panel on Climate Change (IPCC) because another member of the panel publicly warned that global warming would increase storms' frequency and intensity.


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