Study links pollution with warmer oceans

MIAMI — A new study reports more strong links between human-caused global warming and rising ocean temperatures — a key factor in the development and growth of hurricanes.

The report stopped short of asserting a direct relationship between the so-called greenhouse effect and the increased hurricane intensity of recent years. But some scientists and others said it supported their belief that industrial pollution, vehicle emissions and other human impacts on the environment are largely to blame.

"We've now learned that the human-induced buildup of greenhouse gases in the atmosphere appears to be the primary driver of increasing hurricane activity," said Robert Corell, an oceanographer and researcher for the American Meteorological Society.

Not all scientists agree.

"They make a very good case that the trends in sea surface temperatures are at least in part, if not substantially, due to man-made global warming," said Chris Landsea, a meteorologist at the National Hurricane Center in Miami. "But this is not a hurricane study."

The report, written by 19 scientists, found a very high probability that human activities accounted for two-thirds of the increase in water temperature in key hurricane-producing regions of the Atlantic and Pacific during the past century.

But that total increase is quite small — only about 1.2 degrees Fahrenheit. Other studies maintain that Atlantic hurricanes become only 2 percent stronger for every one-degree rise in temperature.

In addition, ocean temperature is just one of many factors in the development of hurricanes.

The study will be published Wednesday in the Proceedings of the National Academy of Sciences.

The study, based on 22 sophisticated computer models, concludes there is an 84 percent chance that at least 67 percent of the increase in sea surface temperatures has been caused by human activity.

It notes that hurricane intensity seems to have been increasing in recent years, and it infers a relationship between the two phenomena, but it does not report a definitive connection.

At the same time, the report widened the gulf between two contingents of climate scientists.

One group, including some authors of the new report, sees growing evidence of links between human-induced global warming, higher sea temperatures and more intense hurricanes.

That group includes Kerry Emanuel of the Massachusetts Institute of Technology, who did not participate in the new study but supports it and issued a seminal report on the subject in 2005 which found that the accumulated power of hurricanes in the Atlantic, Caribbean and Gulf of Mexico had more than doubled since 1970.

The other group agrees that global warming is helping to fuel an increase in sea temperatures but maintains that little or no evidence points to a current effect on hurricanes.

That group includes Landsea. He and Stanley Goldenberg, a researcher at the National Oceanic and Atmospheric Administration's Hurricane Research Division, co-authored a 2001 study that attributed the increase in hurricane activity since 1995 to long-term natural cycles mostly unrelated to global warming.

Landsea also believes that comparative studies such as Emanuel's fail to account for technological improvements that now produce more accurate — and often higher — estimates of a storm's power than were available in the past.

Referring to the new report, Landsea said: "The science in this paper is fine. I agree with it, but it doesn't have a lot to do with the really key questions about global warming and hurricanes."

Florence sideswipes Bermuda

HAMILTON, Bermuda — Hurricane Florence blew out windows, peeled away roofs and knocked out power to thousands of people in Bermuda on Monday, but spared the British island chain massive damage as it skirted past.

Authorities reported a few minor injuries but no deaths from the storm. Tourists remained sheltered inside resort hotels, and officials urged all islanders to stay at home until the second hurricane of the Atlantic season no longer posed a danger. Bermuda's international airport was expected to resume service today.

Florence, a Category 1 hurricane with maximum sustained winds near 85 mph, was not expected to threaten the U.S., forecasters said. The storm did cause high surf and strong rip currents along parts of the eastern U.S. coast, about 640 miles west of Bermuda.

The Associated Press