Wind shear could reduce future hurricane activity

Wind shear could reduce future hurricane activity

Rhett A. Butler, mongabay.com

April 17, 2007

The debate over the impact of global warming on hurricane intensity rages on with a new study published April 18 in Geophysical Research Letters.

The research, conducted by Gabriel A. Vecchi of the National Oceanic and Atmospheric Administration (NOAA) and Brian J. Soden of the University of Miami, suggests that an increase in vertical wind shear in the tropical Atlantic and East Pacific Oceans could inhibit the formation and intensification of hurricanes. The authors note that increased vertical wind shear has historically been associated with “reduced hurricane activity and intensity.”

The results, based on complex climate model simulations for the effects of climate change in the years 2001-2020 and 2081-2100, counter other studies that suggest warmer sea temperatures will spawn ever stronger storms.

Hurricane Katrina. Courtesy of NASA

“Wind shear is one of the dominant controls of hurricane activity, and the models project substantial increases in the Atlantic,” said Gabriel Vecchi, lead author of the paper and a research oceanographer at NOAA’s Geophysical Fluid Dynamics Laboratory in Princeton, N.J.. “Based on historical relationships, the impact of the projected shear change could be comparable in magnitude as that of the warming oceans—with the opposite effect.”

Reviewing results from 18 different models, the researchers project a “robust increase in wind shear over the tropical Atlantic and East Pacific attributable to global warming.” (Yes, the government scientist used the term “global warming”)

“The models send a fairly clear message that we can’t dismiss vertical wind shear as we look at the long-term effect of global warming on hurricanes,” Vecchi said. “This doesn’t settle the issue. It’s one piece of the puzzle that will contribute to what is an incredibly active field of research.”

Global warming’s multiple influences on hurricanes. Courtesy of NOAA

“This study does not, in any way, undermine the widespread consensus in the scientific community about the reality of global warming,” said co-author Brian Soden, an associate professor of meteorology and physical oceanography. “In fact, the shear changes are driven by global warming.”

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