by Bill Chameides | May 8th, 2014
posted by Erica Rowell (Editor)
Wetlands are the largest natural source of atmospheric methane, and methane emissions from wetlands are sensitive to temperature. This means that as temperatures rise, more methane is emitted, causing more warming. A positive feedback that could spell trouble for the climate. (Kelly Fike/USFWS)
Troubles from wetlands’ bubbles?
It was way back in 2008 — one of the very first posts of TheGreenGrok — when we reported that atmospheric concentrations of methane in 2007 were no longer stable. It was a troubling finding.
For one, methane is a potent greenhouse gas, some 25 times more effective as a global warmer than carbon dioxide. And methane concentrations had already risen significantly — growing by more than a factor of two since the 1800s, from about 720 parts per billion to more than 1,720 parts per billion by 1990. Much of that increase could be attributed to human activities: coal mining, rice cultivation, ranching.