Harrowing report says more rainfall won’t end current drought
By Daily Press staff
CRESCENT BAY PARK A report looking at the amount of rainfall the United States receives has found that heavy downpours are now 58 percent more frequent in Los Angeles, Orange and Riverside counties than they were 60 years ago, a sign that global warming is real and is altering local weather patterns.
The report, “When it Rains it Pours: Global Warming and the Rising Frequency of Extreme Precipitation in the United States,” was released by Environment California on Tuesday during a news conference at Crescent Bay Park in Santa Monica.
“At the rate we’re going, what was once the storm of the decade will soon seem like just another downpour,” said Jeremy Mills, federal field association for Environment California, a statewide, citizen-based environmental advocacy organization.
Mills pointed to the rainstorm that hit the southern California region in January 2005 as an illustration of what more extreme rainstorms could mean for the region. That rainstorm, which dumped almost 30 inches of rain on the area in four days, led to extreme flooding and landslides that closed freeways and caused people to be evacuated from their homes.
“More frequent downpours, fueled by global warming, will leave California even more vulnerable to dangerous flooding in years to come,” Mills said.
The report comes as the U.S. Senate Environment and Public Works Committee, chaired by California Sen. Barbara Boxer, is expected to vote today on amendments to the “Lieberman-Warner Climate Security Act of 2007,” a global warming bill that would impose emission limits on electric utility, transportation and manufacturing industries, while offering financial incentives to those companies that do.
Environment California and other groups are calling on Boxer and other lawmakers to strengthen the bill to include greater pollution reduction targets, and also eliminate subsidies to dirty and dangerous energy sources.
“If we are going to solve the problem of global warming, this bill must be substantially strengthened,” Mills said.
A spokesperson for Boxer said that the senator has not made a final decision on the bill, but is expected to do so today.
The report examines trends in the frequency of large rain and snow events across the continental U.S. from 1948 to 2006. Using data from 3,000 weather stations and a methodology originally developed by scientists at the National Climatic Data Center and the Illinois State Water Survey, the report identifies storms with the greatest 24-hour precipitation totals at each weather station, and analyzes when those storms occurred.
Nationally, the report shows that storms with extreme precipitation have increased in frequency by 24 percent across the U.S. since 1948. At the state level, 40 states show a significant trend toward more frequent storms with extreme precipitation, while only one state — Oregon — shows a significant decline.
California experienced a 26-percent increase in extreme rainstorms during the period studied, according to the report.
The increase in the frequency of extreme rainstorms does not mean more water will be available. Scientists expect that, as global warming intensifies, longer periods of relative dryness will mark the periods between extreme rainstorms, increasing the risk of drought.
Originally published in the Santa Monica Daily Press print edition on December 5, 2007. Read the original PDF.