April 5, 2013 by Canadian Underwriter
Extreme precipitation events will become more intense as rising concentrations of greenhouse gases allow for more moisture in a warmer atmosphere, suggests a study led by the National Oceanic and Atmospheric Administration in the U.S.
Extra moisture due to a warmer atmosphere will lead to “notable increases in the most intense precipitation rates,” says an NOAA statement on the study, entitled “Probable maximum precipitation (PMP) and climate change.”
The study was conducted by a team of researchers from the North Carolina State University’s Cooperative Institute for Climate and Satellites-North Carolina (CICS-NC), NOAA’s National Climatic Data Center (NCDC), the Desert Research Institute, University of Wisconsin-Madison, and ERT, Inc.
The study suggests that an increase of 20% to 30% can be expected in the maximum precipitation over large parts of the Northern Hemisphere by the end of the 21st century, assuming greenhouse gas emissions continue to rise at a high rate, NOAA said.
Researchers looked at moisture in the atmosphere, upward motion of air in the atmosphere, and horizontal winds and also “examined climate model data to understand how a continued course of high greenhouse gas emissions would influence the potential maximum precipitation,” the NOAA statement explained.
“While greenhouse gas increases did not substantially change the maximum upward motion of the atmosphere or horizontal winds, the models did show a 20-30 percent increase in maximum moisture in the atmosphere, which led to a corresponding increase in the maximum precipitation value,” the NOAA said.
“We have high confidence that the most extreme rainfalls will become even more intense, as it is virtually certain that the atmosphere will provide more water to fuel these events,” Kenneth Kunkel, senior research professor at CICS-NC and lead author of the paper, said in the NOAA statement.
The report’s data could be used for risk modeling, as well as for the engineering and building sectors, NOAA said.
“Our next challenge is to translate this research into local and regional new design values that can be used for identifying risks and mitigating potential disasters,” Thomas R. Karl, director of NOAA’s NCDC in Asheville, N.C., and co-author on the paper noted in a statement.
“Findings of this study, and others like it, could lead to new information for engineers and developers that will save lives and major infrastructure investments.”
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