Nov. 28, 2006 — Methane, the second-most prominent greenhouse gas, is leveling off in Earth's atmosphere, say scientists.
Concentrations of the gas rose from 1978 throughout the 1980s — with fits and starts and occasional reversals in the 1990s — followed by a flattening out from late 1998 on.
That stabilization is probably from better leak stoppage at oil and natural gas (aka methane) wells, say researchers. Other major sources of methane are cattle, swamps, coal mining, rice paddies, wildfires, biomass burning and termites. At natural gas and oil wellheads, however, it has become both technologically simple and profitable to stop leaks.
"There hasn't been any international campaign to do something about methane," said F. Sherwood Rowland, an atmospheric scientist and Nobel laureate at the University of California at Irvine. "If you start to pay attention (to wellhead leaks), and if it doesn't leak the gas, you can sell it."
Rowland is the lead author on the paper announcing the methane leveling off in the latest issue of Geophysical Research Letters. He was also involved in international efforts to ban manmade chlorofluorocarbons (CFCs), chemicals blamed for the seasonal annihilation of ozone layers over Earth's polar regions.
