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January 19, 2005

Landsea on Hurricanes

Posted to Author: Others | Climate Change

Author: Chris Landsea

It may be worth pointing out that last October Chris Landsea prepared a primer on hurricanes and climate change for Prometheus. We thought that it might be worth re-posting his views.

Hurricanes and Global Warming
Chris Landsea (

There are no known scientific studies that show a conclusive physical link between global warming and observed hurricane frequency and intensity. Whatever suggested changes in hurricane activity that might result from global warming in the future are quite small in comparison to the large natural variability of hurricanes, typhoons and tropical cyclones. For example, the latest GFDL global warming study suggested about a 5% increase in the winds of hurricanes 80 years in the future. This contrasts with the more than doubling that occur now in numbers of major hurricanes between active and quiet decades in the Atlantic basin.

If global warming is influencing hurricane activity, then we should be seeing a global change in the number and strength of these storms. Yet there is no evidence of a global increase in the strength and frequency of hurricanes, typhoons, and tropical cyclones over the past several years.

Beginning in 1995, there has been an increase in the frequency and intensity of hurricanes in the Atlantic basin. However, this increase is very likely a manifestation of a natural multi-decadal cycle of Atlantic hurricane activity that has been occurring likely for the last few hundred years. For example, relatively few Atlantic major hurricanes were observed in the 70s, 80s and early 90s, but there was considerable activity during the 40s, 50s and early 60s. Also, the period from 1944 to 1950 was particularly infamous for Florida - with 11 hurricanes hitting the state during those years.

Total U.S. direct damages from Atlantic hurricanes this year will be on the order of $30 billion, making it about equal to the most damaging year on record - 1992 with the landfall of Hurricane Andrew. However, such increased destruction from hurricanes is to be expected because of the massive development and population increases along the U.S. coastline and in countries throughout the Caribbean and Central America. There is no need to invoke global warming to understand both the 10 years of active hurricane seasons and the destruction that occurred both in Florida and in Haiti this season. The former is due to natural cycles driven by the Atlantic Ocean and the latter is due to societal changes, not due to global warming.

Posted on January 19, 2005 02:26 PM


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