Jun 2, 2006

New Studies: Hurricane Intensity Rising

Two new studies released earlier this week conclude that hurricane intensity is increasing with increases in global temperature. In an earlier post I noted a study from the Georgia Institute of Technology that saw a correlation between rising water temperatures and stronger, more damaging hurricanes. Early this week both Purdue University and Pennsylvania State University studies reached similar conclusions. This New York Times article emphasizes the hotly debated nature of these studies. They cannot be read as conclusive, but certainly as very interesting and concerning.

The Purdue scientists found that their results matched earlier work by Kerry A. Emanuel, a hurricane expert at M.I.T. Dr. Emanuel has argued that global warming, specifically the warming of the tropical oceans, is already increasing the power expended by hurricanes.

The approach used by the Purdue researchers, concentrating on what is called reanalysis data, has never been tried for this purpose before, Dr. Huber said in an interview, adding, "We were surprised that it did as well as it did."

In a statement accompanying the release of the study, Dr. Huber said the results were important because the overall measure of cyclone activity, whether through more intense storms or more frequent storms, had doubled with a one-quarter-degree increase in average global temperature.

In the other new study, Dr. Emanuel and Michael E. Mann, a meteorologist at Pennsylvania State University, compared records of global sea surface temperatures with those of the tropical Atlantic and said the recent strengthening of hurricanes was attributable largely to the rise in ocean surface temperature.

The impact of stronger storms is already taking a toll on the environment and damaging sensitive ecosystems. After last year's deluge of hurricanes the entire gulf region of the United States experienced multiplicative damage. As per the Baltimore Sun:

Throughout the Gulf Coast region from Texas to Florida, barrier islands have been battered by wind and waves, leaving many fragmented and submerged.

The Chandeleur Islands off Louisiana's coast were stripped clean by Katrina, submerging much of the 40-mile-long, uninhabited chain and leaving the mainland more vulnerable in the coming hurricane season.

"It takes a long time for these dunes to re-establish naturally, so the next storm that comes along will have an easier job overtopping the islands and flooding inland areas," said oceanographer Abby Sallenger of the U.S. Geological Survey.

Louisiana had been losing coastal wetlands at a rate of about 25 square miles a year, scientists say. It is estimated that Katrina caused a loss of 118 square miles of wetland marshes.

"What potentially could happen if you take away the barrier islands, the wetlands could even disappear faster," Sallenger said. "The marsh itself will just disintegrate, and it supports an incredibly rich ecosystem."

Another recent study shows that New Orleans is simply not ready for another major hurricane and the impact could be devastating. But Florida's ecosystem is also hanging in the balance.

"These hurricanes are just taking big chunks of our landscape," Doyle said.

"It could eventually be the threshold that tips the bucket and leads freshwater systems to become brackish ... and the whole system kind of collapses. We now have this game board set with certain things in place, and in combination with more frequent hurricanes it can aggravate the situation in terms of sustainability in our social, agricultural and natural systems."

In Florida, where the Everglades has become a managed network of canals and levees, scientists face the daunting task of controlling more water from frequent storms to keep developed areas from flooding and to cleanse agricultural runoff of fertilizers and pesticides before it reaches surrounding wetlands.

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