Freakonomics and Hurricanes

Today I discovered the Freakonomics blog which links off of nytimes.com. For those of you who haven't read "Freakonomics" by Steven Levitt and Stephen Dubner - get on it! The book is incredibly interesting, one of the few non-fiction that I have been able to devour in a few sittings. The basic premise is that a smart, non-biased economist goes around thinking about social,everyday problems from an economics standpoint. He tackles Roe v. Wade and national crime rates, drug gangs, sumo wrestling and more. In my opinion, he is not quite so unbiased - after all, he criticizes (indirectly) both the pro-life stance and the No Child Left Behind Act - but then, we all have biases.



Anyways, I read one of their blog entries written about the possible connection between hurricanes and climate change. The entry just encapsulated a statement that the American Meteorological Association came out with in 2006, which is what follows:


Consensus statements by the workshop participants

1. Though there is evidence both for and against the existence of a detectable anthropogenic signal in the tropical cyclone climate record to date, no firm conclusion can be made on this point.

2. No individual tropical cyclone can be directly attributed to climate change.

3. The recent increase in societal impact from tropical cyclones has been largely caused by rising concentrations of population and infrastructure in coastal regions.

4. Tropical cyclone wind-speed monitoring has changed dramatically over the last few decades leading to difficulties in determining accurate trends.

5. There is an observed multi-decadal variability of tropical cyclones in some regions whose causes, whether natural, anthropogenic or a combination, are currently being debated. This variability makes detecting any long-term trends in tropical cyclone activity difficult.

6. It is likely that some increase in tropical cyclone peak wind-speed and rainfall will occur if the climate continues to warm. Model studies and theory project a 3-5% increase in wind-speed per degree Celsius increase of tropical sea surface temperatures.

7. There is an inconsistency between the small changes in wind-speed projected by theory and modeling versus large changes reported by some observational studies.

8. Although recent climate model simulations project a decrease or no change in global tropical cyclone numbers in a warmer climate there is low confidence in this projection. In addition, it is unknown how tropical cyclone tracks or areas of impact will change in the future.

9. Large regional variations exist in methods used to monitor tropical cyclones. Also, most regions have no measurements by instrumented aircraft. These significant limitations will continue to make detection of trends difficult.

10. If the projected rise in sea level due to global warming occurs, then the vulnerability to tropical cyclone storm surge flooding would increase.

This was interesting as it was - you tend to hear more on the news about how hurricanes are rapidly increasing - due to scary global warming, when in fact we have no certainty yet about the issue. There has been one study published by Greg Holland and Peter Webster which documents an increase in hurricanes correlated to global warming - but the study has little other support from the scientific community. The other interesting part is that the blog includes many posts from readers who seem extremely cynical about global warming - cynical and pretty well educated. One of them even cited Lomberg - The Cynical Environmentalist.