Brian Handwerk in National Geographic:
Grasses and other green growth may produce 10 to 30 percent of Earth’s annual methane output, a new study reports, making plants a surprising—and potentially significant—contributor to global warming.
Until the data were unveiled in this week’s Nature, scientists had believed that plant-related methane formed only in oxygen-free environments, such as bogs.
But a team of European researchers identified a large range of plants that release methane under normal growing conditions. The gas also seeps from dead plant material.
David Lowe is an atmospheric chemist with the National Institute of Water and Atmospheric Research in Wellington, New Zealand. He wrote a review article accompanying the study.
According to Lowe, “We now have the specter that new forests might increase greenhouse warming through methane emissions rather than decrease it by being sinks for carbon dioxide.”
“The identification of a new source should prompt a re-examination of the global methane budget.”