Hydropower Isn't Totally Carbon-Free

A forthcoming study from Washington State University finds that reservoirs—including those created by hydroelectric dams—might produce 25 percent more greenhouse gas emissions than previously thought.

As CrossCut points out, "this could have implications for regions like the Northwest, which rely on hydroelectric power to meet its power demands."

The study looked at other man-made reservoirs as well, such as those used for drinking water and irrigation. Its findings may be surprising:

When all those man-made water bodies are added up, their combined emissions make up 1.5 percent of the world’s greenhouse gas pollution.

Put another way, if reservoirs were a country, they’d be the 8th largest emitter of greenhouse gasses like methane and carbon dioxide.