Records show drop in Atlantic hurricanes

Records show drop in Atlantic hurricanes
January 1, 2001

A science reporter’s ominous voice intones, “Global warming imminent . . .” as a parched desert landscape fills the screen. “Industrial pollutants the cause of . . .” says the voice in verb-deficient mediaspeak over footage of smokestacks spewing clouds of particulate and water vapor (remember, CO2 is invisible). “. . . more severe storms, droughts, floods . . .” it continues, as we see hurricanes crash into coastal homes.

Scary? Sure. True? Hardly.

Hurricanes will not overwhelm the greenhouse-warmed world. There is no trend toward more or more severe hurricanes in the North Atlantic, and in fact published reports show wind speeds from land-falling storms have significantly declined over time.

A new study by Andrew Solow and Laura Moore lends further support to that pattern. Although some hurricane records are available through the late 1800s, most hurricane climatologies are limited to the post-World War II era, when aircraft reconnaissance information became available. So it’s difficult to know, prior to 1946, how many hurricanes existed out over the Atlantic or Caribbean that we never knew about.

Solow and Moore reconstructed annual hurricane numbers based on the observed number of land-falling storms. Using statistical probabilities and the assumption that the proportion of hurricanes that make landfall is roughly constant over time, they estimated the total number of hurricanes in the North Atlantic back to 1930.

The annual number of storms has declined from an average of 7.4 in 1930 to 5.4 in 1998. Of course, the confidence level depends on their assumption of no change in how many reach land. But Solow and Moore tested that assumption by looking for changes in this percentage during the aircraft reconnaissance period of 1946-1998, finding no significant change.

This research provides yet another chunk of evidence that the gloomy scenarios proffered by our national TV correspondents are overblown. Or, using their parlance, “Global warming . . . not a problem.”


References

Solow, A., and L. Moore, 2000. Testing for a trend in a partially incomplete hurricane record. Journal of Climate, 13, 3696-3699.

Intergovernmental Panel on Climate Change, 1996. Climate Change, 1995: The Science of Climate Change. Cambridge University Press, Cambridge. 542 pp.