Stronger hurricanes on a warmer Earth

From Ocean Navigator #90
May/June 1998
Hurricane activity will be increasing in intensity if global warming continues at the current rate, according to a new study by NOAA scientists.

Using hypothetical models, like this view of Hurricane Andrew in 1992, scientists predict stronger hurricanes will result from global warming.
   Image Credit: Courtesy Geophysics Fluid Dynamics Lab

Using sophisticated computer models that also predict actual hurricanes, meteorologists at the Geophysical Fluid Dynamics Laboratory in Princeton, N.J., concluded that hurricanes will intensify from 5% to 12% in the next 70 to 120 years.

“If the CO2 in the atmosphere continues to increase at the current rate, roughly 1% per year, then we could see an increase in hurricane intensity,” said Bob Tuleya, a research meteorologist at GFDL, who was one of three meteorologists to develop the computer model. The hurricane simulator was first used in actual forecasts in 1995.

Determining that global warming would generate more intense hurricanes was achieved by simulating a world that had been warmed progressively at the current rate for 70 to 120 years. “We took 51 cases in the hypothetical greenhouse-warming world and made a model just like we would during a real hurricane,” Tuleya added. “But hurricane forecasting isn’t an exact science; the models give us possible scenarios.”

These projects are not just idle speculation, however. Similar results have been found by other studies, according to Tuleya. “Other scientists have made theoretical conclusions without computers and models that draw the same conclusions as GFDL. There’s a definite trend.”

Hurricane increase from global warming is the result of warmer sea-surface temperatures. For a hurricane to form, surface temperatures must be above 80° F. The Intertropical Convergence Zone, a swath of warm air that circles the globe at various latitudes throughout the year, heats sea-surface temperatures seasonally, bringing the temperature up in mid-summer to the requisite 80°.

“If we see an increase in heat in the equatorial regions, this will result in more moisture in the atmosphere and consequently provide more potential fuel for tropical depressions and hurricanes,” said Michael Carr, president of Ocean Strategies, a weather and routing information company based on Peaks Island, Maine.

By Ocean Navigator