ARE the most powerful, devastating hurricanes becoming the norm? Hurricane researchers are divided over the issue. When hurricane Dean reached category 5 strength in the Caribbean on Monday night, 2007 became the fourth year out of the past five to host the most intense category of storm - an unparalleled record.
"We're in transition now to a new regime," with warmer sea-surface temperatures fuelling more and stronger storms, says Peter Webster of the Georgia Institute of Technology in Atlanta, who has reported both that hurricanes are becoming more intense and that storm frequency in the North Atlantic began to rise significantly in 1995 (Science, DOI: 10.1126/science.1116448).
Category 5 storms have been uncommon: during 43 of the seasons since 1940, no such storms were recorded. The only time before now that a category 5 storm has been recorded during three out four years was between 1958 and 1961. ...
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