Friday, April 24, 2009
Methane Increases in Atmosphere for Second Year in a Row
There is more evidence that atmospheric levels of the greenhouse gas methane are trending upward again after a decade of stability. This bad news comes from the National Oceanic and Atmospheric Administration (NOAA). Methane doesn’t last nearly as long in the atmosphere as the number one greenhouse gas carbon dioxide but an equivalent amount of methane can trap much more heat. A big question is why are methane levels increasing? The answer that we do not want is that the main source of the increase is melting permafrost in the Arctic region. That would mean that the dreaded positive feedback mechanism of global warming releasing methane from the permafrost which in turn would cause more global warming, etc. has kicked in enough to show up in atmospheric measurements. Hopefully there is some other explanation.