Executive Director, Environment Texas
Executive Director, Environment Texas
Extreme Downpours Up 29 Percent in Texas
AUSTIN— A massive downpour in Austin this weekend that led to significant flooding and cancellation of the Austin City Limits festival is consistent with scientific predictions of global warming, said Austin non-profit Environment Texas. The group pointed to their 2012 report confirming that extreme rainstorms are happening 29 percent more frequently in Texas since 1948.
“As the old saying goes, when it rains, it pours. Global warming is creating a new boom and bust cycle, with severe drought interrupted by heavier extreme rainstorms,” said Luke Metzger, Director of Environment Texas. “We need to heed scientists’ warnings that this dangerous trend is linked to global warming, and do everything we can to cut carbon pollution today.”
Based on an analysis of state data from the National Climatic Data Center, the report found that heavy downpours that used to happen once every 12 months on average in Texas now happen every 9.3 months on average. Moreover, the biggest storms are getting bigger. The largest annual storms in Texas now produce ten percent more precipitation, on average, than they did 65 years ago.
Scientists have concluded that the rise in the frequency and severity of heavy rainstorms and snowstorms is linked to global warming. Warming increases evaporation and enables the atmosphere to hold more water, providing more fuel for extreme rainstorms and heavy snowstorms.
The Environment Texas Research and Policy Center report, When It Rains, It Pours: Global Warming and the Increase in Extreme Precipitation from 1948 to 2011, examines trends in the frequency of and the total amount of precipitation produced by extreme rain and snow storms across the contiguous United States from 1948 to 2011. Using data from 3,700 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. The report also examines trends in the amount of precipitation produced by the largest annual storm at each weather station.
Nationally, the report found that storms with extreme precipitation increased in frequency by 30 percent across the contiguous United States from 1948 to 2011. Moreover, the largest annual storms produced 10 percent more precipitation, on average.
Key findings for Texas and the Southwest include:
· Extreme rainstorms and snowstorms are becoming more frequent. Texas experienced a 29 percent increase in the frequency of extreme rainstorms from 1948 to 2011. In other words, heavy downpours or snowstorms that happened once every 12 months on average in 1948 now happen every 9.3 months, on average.
· Storms with extreme precipitation increased in frequency by 31 percent in the Southwest during the period studied. The biggest rainstorms and snowstorms are getting bigger. The amount of precipitation released by the largest annual storms in Texas increased by ten percent from 1948 to 2011.
Metzger was careful to note that an increase in the frequency and severity of extreme rainstorms does not mean more water will be available for human use. Hotter temperatures fuel extreme rainstorms by increasing rates of evaporation. At the same time, however, that evaporation increases soil dryness. Moreover, scientists expect that, as global warming intensifies, longer periods with relatively little precipitation will tend to mark the periods between heavy rainstorms. As a result, droughts are likely to become more frequent and severe in some regions of the United States. Texas is suffering through prolonged drought.
According to the most recent science, the United States must reduce its total global warming emissions by at least 35 percent below 2005 levels by 2020 and by at least 85 percent by 2050 in order to prevent the most devastating consequences of global warming. Environment Texas highlighted a proposal from the Obama administration to limit carbon pollution standards for new power plants as a critical step toward meeting these pollution reduction targets. The U.S. Environmental Protection Agency will hold a listening session on the proposed rule in Dallas on November 7.
“How serious this problem gets is largely within our control – but only if we act boldly to reduce the pollution that fuels global warming,” said Metzger. “We applaud the Obama administration for their proposal to cut carbon pollution from new power plants, and urge them to move forward with finalizing this critical initiative.”