Thursday, June 1, 2006
William Gray and Colorado State University predicted yesterday that the Atlantic season will see nine hurricanes and an 82% probability that the US coast would be hit by a major hurricane. This is far above the average 50-50% chance of a major hurricane making landfall in the US. Planet Ark story
As usual, Gray totally discounted the impact of anthropogenic global warming. However, John Schwartz of the NY Times reported today that climate researchers at Purdue and MIT separately reported new evidence supporting the idea that global warming is causing stronger hurricanes. Schwartz report The Purdue paper by Huber and Sriver, appearing in a forthcoming issues of Geophysical Research Letters, calculates total damage caused by storms worldwide, using data normally applied to reconciling weather forecast models with observed weather events. The Huber and Sriver results were consistent with earlier work by Kerry Emanuel of MIT. Emanuel has argued that global warming, specifically the warming of the tropical oceans, is increasing the power expended by hurricanes.
Another new study by Emanuel and Mann published in EOS compared global sea surface temperatures data with tropical Atlantic data and attributed recent strengthening of hurricanes to the rise in ocean surface temperature. Using increasingly sophisticated climate models that account for the impact of aerosols, Emanuel and Mann question the theory that hurricane activity fluctuates over a natural decadenal climate cycle. Their analysis estimated human influences on climate compared to possible natural cyclical influences, finding "anthropogenic factors are likely responsible for long-term trends in tropical Atlantic warmth and tropical cyclones." They question the theory of the Atlantic multi-decadal signal, a natural climate cycle, as an explanation of the surges and declines over decades of hurricane activity. Instead, more sophisticated climate models and more precise global temperature data suggest that there is a linear increase in hurricanes related to the increase in Atlantic sea surface temperatures, rather than a natural cycle.
Meanwhile, Jeb Bush met with Peter Webster and Judith Curry of the Georgia Institute of Technology, who published research last year showing an increase in global hurricane intensity, with a doubling of the number of Category 4 or 5 hurricanes since 1970. That increase coincides with a rise of nearly 1 degree Fahrenheit in ocean surface temperatures. Webster and Curry agree with the cyclical theory and accept that the Atlantic basin is experiencing a natural cyclical increase in hurricanes. However, Webster and Curry argue that cycle does not explain such a dramatic increase in strong storms. Increasing global surface temperatures cause warmer water, fueling more intense hurricanes. AP report