Scientists from Tulane and the University of New Hampshire using NASA satellite data calculate that Hurricane Katrina killed or severely damaged 320 million large trees in Gulf Coast forests. The damaged trees subsequently released large quantities of CO2 to the atmosphere—the equivalent of 60-100% of the net annual carbon sink in all US forest trees. Why? Because dead trees no longer photosynthesize and can't store carbon. Plus, dead wood is consumed by decomposers whose communities grow in keeping with the bumper crop, and who then "exhale" large quantities of CO2 into the atmosphere.
The August 2005 hurricane damaged or destroyed 5 million acres of forest across Mississippi, Louisiana and Alabama. "It is surprising to learn that one extreme event can release nearly as much carbon to the atmosphere as all U.S. forests can store in an average year," said Diane Wickland, manager of the Terrestrial Ecology Program at NASA Headquarters in Washington. Climate change forecasts predict more larger and powerful storms like Katrina more frequently in the future.
Julia Whitty is Mother Jones' environmental correspondent. You can read from her new book, The Fragile Edge,and other writings, here.