Atmospheric methane rise stalls
The stabilization of atmospheric methane over the past 7 years could slow global warming.
The growth of methane levels in the atmosphere has slowed over the past several decades, and the past 7 years have seen only tiny fluctuations of the powerful greenhouse gas in the troposphere. That downturn could affect global warming trends, scientists say in the November 23 issue of Geophysical Research Letters.
Atmospheric chemists from the University of California, Irvine, found that methane concentrations corresponded to shifts in ethane, produced in large-scale fires. They found that global methane levels barely increased from December 1998 to December 2005 and that the fluctuations matched biomass burning related to the El Niņo–Southern Oscillation.
Although it may be temporary, the current stabilization of methane—more than 20 times more powerful a greenhouse gas than CO2—could provide some reprieve from current global warming trends. The new data make projected methane increases in 10 scenarios from the most recent report of the Intergovernmental Panel on Climate Change seem “quite unlikely,” the team writes.
