When It Rains, It Pours…and Increases Soil Erosion Potential in a Changing Climate

Roots are exposed due to soil erosion during a flooding event. Soil erosion can create unstable land conditions in ecosystems and communities. Photo by Randy Cyr, Greentree, Bugwood.org.

Anyone who has seen a gully carved by water flowing over land or a muddied creek following a rainstorm has witnessed soil erosion. Beyond its messiness, water-caused soil erosion can have far reaching impacts. When nutrients and organic matter in soils are washed away, decreased soil fertility affects food production, sediment entering streams and rivers threatens water quality and wildlife, shifting soils create unstable land conditions in ecosystems and communities, and disturbed soils with reduced carbon storage abilities can contribute to global warming. In a changing climate with altered precipitation patterns, some areas in the United States may be particularly vulnerable to increased soil erosion and these related problems. U.S. Forest Service researchers and partners at North Carolina State University* have identified these areas in a recently published study.

The researchers considered nine climate scenarios with varying precipitation projections based on different levels of climate-warming greenhouse gas emissions. For the years 1970-2090, they examined changes in the potential for soils to be eroded by rainfall, which depends on a combination of factors, including rainfall intensity, soil characteristics, slope of the land, and type of land cover. With this information, they generated maps showing changes in erosion potential and identified which watersheds across the United States could be most vulnerable to soil erosion in the years to come.

“Our results show that, on average, the potential for soil erosion will increase with time according to all nine climate scenarios, but changes in potential erosion could vary widely across the country,” says Ge Sun, a research hydrologist with the Eastern Forest Environmental Threat Assessment Center. “Overall, states in the Northeast and Northwest could see the biggest increase in soil erosion potential simply because precipitation amount and variability in these areas are projected to rise in the next 90 years. Future soil erosion trends in the Midwest and Southwest are less certain.” Relatively small areas of agricultural land and steep terrain in New York, Washington, Oregon, and Idaho appear to be the most vulnerable to soil erosion according to the researchers’ analysis. Other areas of land with high erosion potential stretch across Vermont, Ohio, Indiana, Maryland, and Illinois.

The information presented in this study is useful to managers of forests, farms, and water resources, explains Steve McNulty, Eastern Threat Center research ecologist and Director of the newly formed USDA Southeast Regional Climate Hub, or SERCH. “Our ultimate goal in this research was to provide guidance to range, agricultural, and forest land managers and decision makers about options for adapting to changing conditions. Soil erosion control and watershed restoration can make working lands more resilient and able to withstand impacts from climate variability.”

Read the full text of the article.

For more information, contact Ge Sun at gesun@fs.fed.us.

*Catalina Segura, the study’s lead author and former North Carolina State University collaborator, is now an assistant professor at Oregon State University.

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