July 2, 2008
Global Warming Not Being Factored Into Weather Forecasts
The latest string of floods to hit the U.S. Midwest is providing troublesome clues to conservation experts who claim that many forecasts fail to consider the affects global warming on weather patterns.
"Although no single weather event can be attributed to global warming, it's critical to understand that a warming climate is supplying the very conditions that fuel these kinds of weather events," said Amanda Staudt, a climate scientist with the National Wildlife Federation.
Floods of such magnitude are only supposed to occur once every 500 years, but this is the second since 1993.
However, these estimates maybe flawed because they may be based on mistaken assumptions that flood patterns do not change over time, said Nicholas Pinter of Southern Illinois University.
In the last 35 years, there have been four floods in the Mississippi River basin that qualified as 100-year floods or higher according to the Army Corps' analysis, Pinter said.
"It is an impossibility that those numbers can be correct," Pinter told reporters. "These are not random events. We're getting a systematic pattern of floods larger and/or more frequent than currently estimated by those calculations."
Staudt said that warmer air holds more water, which could usher in more heavy precipitation to the central U.S. Big Midwestern storms that used to be seen every 20 years or so will likely occur every four to six years by century's end, she said.
Pinter said the Army Corps analysis fails to include any notion of climate change as a mechanism to change flood patterns along the Mississippi.
He said the analysis also rejects the effects of land use and navigation construction over that period.
"We suggest the current flood, sadly, is a confirmation that ... these numbers are probably invalid, underestimating the occurrence of floods up and down this river for a variety of mechanisms," Pinter said.
In light of recent flooding across the Midwest, the National Wildlife Federation, a non-profit conservation group, called on Congress to revise the National Flood Insurance Reform and Modernization Act.
"While there may have been an expectation that such floods would only happen every 500 years, scientists now warn that climate change will make such floods far more frequent," federation president Larry Schweiger wrote in a letter to ranking members of the Senate Banking Committee and House Financial Services Committee.
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