U.S. climate researchers predict heavier rains, snows as globe warms

A military truck sits in the water on St. Louis Avenue between 8th and 9th Streets as personnel help residents (two women, one man and family pet) evacuate with their essential belongings from their apartment as Hurricane Sandy floods Ocean City.

A recently published study led by U.S. government climate researchers predicts warming global temperatures will mean more moisture in the air, and thus heavier precipitation extremes.

The research, reported in the peer-reviewed academic journal Geophysical Research Letters, called the conclusions "the most scientifically sound projection."

"Climate model simulations indicate a substantial future increase in mean and maximum water vapor concentrations," they wrote in the abstract of the study.


For the northern hemisphere, that could mean a 20-30 percent increase in a statistic known as "maximum possible precipitation" over the next century under current greenhouse gas emissions growth rates. The authors of the study include researchers from the National Climatic Data Center in Asheville, N.C.; North Carolina State University's Cooperative Institute for Climate and Satellites-North Carolina; the Desert Research Institute, University of Wisconsin-Madison, and ERT Inc.

The study examined three factors that influence maximum possible precipitation: atmospheric moisture, upward motion of air in the atmosphere and horizontal winds. They found that an expected increase in moisture to most contribute to precipitation changes, with no substantial change in the atmospheric winds.


"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, a senior research professor at the N.C. State institute and lead author of the paper, said in a statement.

The maximum precipitation statistics are used in engineering and insurance to plan and account for risk from severe weather events to buildings, dams and culverts.

The National Weather Service has regularly produced maximum precipitation estimates in the past, but does so less frequently than in the past because of budget cuts. The most recent estimates available for Maryland and much of the eastern U.S. was last updated in 1982.