Global warming is likely to reduce the number of hurricanes that occur each year, according to two new studies by forecasters who previously claimed global warming would cause more hurricanes.
Knutson: Fewer Future Hurricanes
Global warming is not to blame for the spike in hurricanes that occurred earlier this decade, research meteorologist Tom Knutson reported in the June issue of Nature Geoscience. Knutson also reported global warming will likely reduce the number of future hurricanes.
According to Knutson, the number of Atlantic Ocean hurricanes will decline by 18 percent by the end of the century, and the number of those making North American landfall will decline by 30 percent. The number of the most powerful storms–those with winds over 110 miles per hour–will decline by 8 percent.
The study further predicts hurricanes and tropical storms will become somewhat wetter, which may be welcome news to southeastern states that endure periodic droughts, particularly during the summer/fall hurricane season.
Emanuel: Atlantic Coast Reprieve
The Knutson study follows one published by prominent global warming alarmist Kerry Emanuel and two other scientists.
The Emanuel study, published in the March 2008 issue of the Bulletin of the American Meteorological Society, concluded, “A new technique for deriving hurricane climatologies from global data, applied to climate models, indicates that global warming should reduce the global frequency of hurricanes, though their intensity may increase in some locations.”
The study comes as a tremendous concession from Emanuel, who has long stoked media fears of global warming causing more hurricanes.
Emanuel ran several computer models designed to recreate past hurricane activity. He then used that past hurricane behavior, along with global warming computer models developed by the United Nations’ Intergovernmental Panel on Climate Change, to predict future hurricane activity.
According to the study, “The model consensus has slightly decreased frequency of events in the Caribbean and in the western portion of the Atlantic main development region.”
Regarding the intensity of future storms, Emanuel reports the models are split. Some indicate hurricane and tropical storm intensity will remain stable or decline, whereas others predict the storms’ overall intensity will increase somewhat. Emanuel sided with the models suggesting more intensity, but he acknowledged large uncertainties remain.
Reaching a Consensus
The Emanuel study directly contradicts sensationalist media assertions of global warming being responsible for recent hurricane activity. Assuming the computer models are correct, Emanuel reported, “the greater part of the large increase in power dissipation over the past 27 [years] cannot be ascribed to global warming.”
That finding comports with longstanding reports from scientists at the National Hurricane Center and National Oceanic and Atmospheric Administration.
For example, National Hurricane Center scientist Chris Landsea said the evidence of global warming having any effect on hurricanes is “pretty darn tiny.”
Similarly, William Gray of Colorado State University, who is widely regarded as one of the foremost hurricane experts in the world, pointed out at the March 2008 International Conference on Climate Change that real-world evidence never supported the assertion global warming was causing an increase in hurricane activity.
When computer models based on speculative assumptions predict one thing but real-world evidence shows exactly the opposite, science tells us we should trust the real-world evidence, Gray noted.
John Dale Dunn, M.D., J.D. ([email protected]) is a civilian emergency medicine faculty member at the Carl R. Darnall Army Medical Center and policy advisor to The Heartland Institute and the American Council on Science and Health.
For more information …
“Hurricanes and Global Warming, Results from Downscaling IPCC AR4 Simulations,” Kerry Emanuel, Ragoth Sundararajan, and John Williams, Bulletin of the American Meteorological Society, Volume 89, Issue 3 (March 2008), pp. 347-367: http://ams.allenpress.com/archive/1520-0477/89/3/pdf/i1520-0477-89-3-347.pdf
“Simulated reduction in Atlantic hurricane frequency under twenty-first-century warming conditions,” Thomas R. Knutson, Joseph J. Sirutis, Stephen T. Garner, Gabriel A. Vecchi and Isaac M. Held, Nature Geoscience 1, 359 – 364 (2008), Published online: 18 May 2008: http://www.nature.com/ngeo/journal/v1/n6/abs/ngeo202.html