Saturday, May 2, 2009

Researchers find that tree-killing hurricanes could contribute to global warming

Tulane University: A first-of-its kind, long-term study of hurricane impact on U.S. trees shows that hurricane damage can diminish a forest’s ability to absorb carbon dioxide, a major contributor to global warming, from the atmosphere. Tulane University researchers from the Department of Ecology and Evolutionary Biology examined the impact of tropical cyclones on U.S. forests from 1851–2000 and found that changes in hurricane frequency might contribute to global warming. The results will be published in an upcoming issue of the Proceedings of the National Academy of Sciences.

Trees absorb carbon dioxide as they grow, and release it when they die -- either from old age or from trauma, such as hurricanes. The annual amount of carbon dioxide a forest removes from the atmosphere is determined by the ratio of tree growth to tree mortality each year.

When trees are destroyed en masse by hurricanes, not only will there be fewer trees in the forest to absorb greenhouse gases, but forests could eventually become emitters of carbon dioxide, warming the climate. And other studies, notes Tulane ecologist Jeff Chambers, indicate that hurricanes will intensify with a warming climate.

“If landfalling hurricanes become more intense or more frequent in the future, tree mortality and damage exceeding 50 million tons of tree biomass per year would result in a net carbon loss from U.S. forest ecosystems,” says Chambers.

…“The bottom line,” says Chambers, “is that any sustained increase in hurricane tree biomass loss above 50 million tons would potentially undermine our efforts to reduce human fossil fuel carbon emissions.”….

A forest near Bruchhausen, Germany, six months after Hurricane Kyrill, shot by Vincent Bass, Wikimedia Commons, under the terms of the GNU Free Documentation License, Version 1.2 ... Although, if it's in Europe, wouldn't it be called a windstorm?

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