Global warming has made stronger hurricanes, including those in the Atlantic such as Katrina, an authoritative panel on climate change has concluded for the first time, participants in the deliberations said Thursday.
During marathon meetings in Paris, the Intergovernmental Panel on Climate Change approved language that said an increase in hurricane and tropical cyclone strength since 1970 "more likely than not" can be attributed to man-made global warming, according to Leonard Fields of Barbados and Cedric Nelom of Surinam.
In its last report in 2001, the same panel had said there was not enough evidence to make such a conclusion.
"It is very important" that the language is so strong this time, said Fields, whose country is on the path of many hurricanes. "Insurance companies watch the language, too."
The panel did note that the increase in stronger storms differs in various parts of the globe, but that the storms that strike the Americas are global warming-influenced, according to another participant.
Fields said that the report notes that most of the changes have been seen in the North Atlantic.
The report — scheduled to be released Friday morning — is also a marked departure from a November 2006 statement by the World Meteorological Organization, which helped found the IPPC.
The meteorological organization, after contentious debate, said it could not link past stronger storms to global warming.
The debate about whether stronger hurricanes can be linked to global warming has been dividing a scientific community that is otherwise largely united in agreeing that global warming is human-made and a problem.
Massachusetts Institute of Technology professor Kerry Emanuel, who pioneered much of the research linking global warming to an uptick in hurricane strength, looked at the original language in an IPCC draft and called it "a pretty strong statement."
"I think we've seen a pretty clear signal in the Atlantic," Emanuel said. The increase in Atlantic hurricane strength "is so beautifully correlated with sea surface there can't be much doubt that there's a relationship with sea surface temperature."
But U.S. National Hurricane Center scientist Christopher Landsea has long disagreed with that premise. While he would not comment on the IPCC decision, Landsea pointed to the WMO statement last fall.