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SNAPSHOT: Soil and Methane

Soil is absorbing less methane than expected, and that’s bad news for climate change, according to a study published in the Proceedings of the National Academy of Sciences journal.

Methane, a greenhouse gas, contributes to global warming. When methane in the atmosphere is absorbed by soil, bacteria in the soil consume it. But higher rainfall — also a result of climate change — has made soil wetter in some places. Wet soil absorbs less methane. That means less methane is consumed by bacteria.

The study was co-authored by Professor Peter Groffman of Brooklyn College and The Graduate Center’s Advanced Science Research Center. Groffman has spent more than 20 years studying the soil at one site in Baltimore and another in New Hampshire’s White Mountain National Forest.

A lush green forest

His research showed decreases of methane gas uptake of 53 to 89 percent over time. Lower rates of methane absorption have also been documented around the world, according to a review of 317 papers by Xiangyin Ni, a doctoral student from Sichuan Agricultural University who spent a year at the ASRC.

Climate change models are “overestimating how much methane is being captured by forest soil,” Groffman said, “and that means a lot more of this greenhouse gas is ending up in our atmosphere a lot faster than we believe.” Read more.

SNAPSHOT is SUM’s new afternoon science brief.