Mapping methane emissions from rivers around globe reveals surprising sources

Emily Stanley - Freshwater ecosystems account for half of global emissions of methane, a potent greenhouse gas that contributes to global warming. Rivers and streams, especially, are thought to emit a substantial amount of that methane, but the rates and patterns of these emissions at global scales remain largely undocumented. An international team of researchers, including University of Wisconsin-Madison freshwater ecologists, has changed that with a new description of the global rates, patterns and drivers of methane emissions from running waters. Their findings and point to land-management changes and restoration opportunities that can reduce the amount of methane escaping into the atmosphere. The new study confirms that rivers and streams do, indeed, produce a lot of methane and play a major role in climate change dynamics. But the study also reveals some surprising results about how - and where - that methane is produced. "We expected to find the highest methane emissions at the tropics, because the biological production of methane is highly sensitive to temperature," says Emily Stanley , a professor at UW-Madison's Center for Limnology and co-author of the Nature report.