A U.S. government study shows global levels of atmospheric carbon dioxide increased by 19 billion tons last year, while methane rose by 27 million tons.
National Oceanic and Atmospheric Administration scientists said the findings are part of the agency’s annual update of its greenhouse gas index that tracks data from 60 sites around the world.
Researchers said 20 percent of the 2007 fossil fuel emissions of carbon dioxide are expected to remain in the atmosphere for thousands of years.
Methane levels rose last year for the first time since 1998. NOAA scientists said methane is 25 times more potent as a greenhouse gas than carbon dioxide but there’s far less of it in the atmosphere.
Rapidly growing industrialization in Asia and rising wetland emissions in the Arctic and tropics are the most likely causes of the methane increase, said NOAA scientist Ed Dlugokencky.
“We’re on the lookout for the first sign of a methane release from thawing Arctic permafrost,” said Dlugokencky. “It’s too soon to tell whether last year’s spike in emissions includes the start of such a trend.”