The chief of the National Hurricane Center yesterday said the intensity of hurricanes slamming the Gulf Coast is not the result of global warming but rather is part of a "normal cycle" that likely will result in one or two more severe storms before the season ends Nov. 30.
"Hurricanes, and especially major hurricanes, are cyclical," said Max Mayfield, the center's director. "We'll have a few decades of really active hurricanes, and then inactive periods, followed by active periods again."
A cycle of severe storms plagued the U.S. from the 1940s through the 1960s when sea surface temperatures were warmer than normal. Those temperatures cooled in the 1970s and for the next 25 years, Mr. Mayfield told CBS' "Face the Nation." When sea temperatures began rising again in 1995, the severity of storms increased.
"So I think that this activity that we're in can be explained without invoking global warming. And the bad news here is that we are in this active period, and the research meteorologists tell us that it may last another 10 or 20 years," Mr. Mayfield said.
"We think that this is just a normal cycle," Mr. Mayfield told ABC's "This Week" program.
Some environmentalists and scientists blame global warming for the ferocity of this season's storms. John Lawton, chairman of the Royal Commission on Environmental Pollution, told the London Times before the arrival of Hurricane Rita that "if this makes the climate loonies in the States realize we've got a problem, some good will come out of a truly awful situation."
"If what looks like it is going to be a horrible mess causes the extreme skeptics about climate change in the U.S. to reconsider their opinion, that would be an extremely valuable outcome," Mr. Lawton said.
Asked by ABC host George Stephanopoulos how to prepare for hurricanes, Mr. Mayfield said anyone who lives in the potential path of a storm already should have an evacuation plan.
"The battle against a hurricane is really one outside the hurricane season," Mr. Mayfield said.
Some New Orleans levees are still undergoing repairs from Hurricanes Katrina and Rita, but Mayor C. Ray Nagin today hopes to allow business owners on the West Bank and Algiers to return to some parts of the city to assess damage.
Coast Guard Vice Adm. Thad Allen says he accepts this limited entry plan, but warns that levee integrity must be considered before the city is fully repopulated.
The Army Corps of Engineers said the levees could handle a surge of 7 feet in the wake of Katrina, but the surge from Rita neared 8 feet and pushed a new flood of water back into the already devastated 9th Ward.
"We should be eternally worried until the levee structure has been repaired to pre-Katrina heights and then the final decisions on what that levee system needs to be to create the boundary conditions for a new city of New Orleans," said Adm. Allen, who predicted that the levee repairs will not be completed until late June.
"In the meantime, any re-entry into the city, any type of development or anything else, has to take into account what will happen if it exceeds the capacity of the levees, and you have to have an evacuation plan in place," Mr. Allen said.
"As I've said over the last couple of weeks, as far as their re-entry into New Orleans, really the long pole in the tent is: Once you have people back in, do you have a way to get them out, to notify them and so forth? And those are the types of conditions of entry that have to be established before you go on beyond the business district and the West Bank," Mr. Allen said.