What is methane's contribution to global warming?
What the science says...
While methane is a more potent greenhouse gas than CO2, there is over 200 times more CO2 in the atmosphere. Eg - CO2 levels are 380 ppm (parts per million) while methane levels are 1.75ppm. Hence the amount of warming methane contributes is calculated at 28% of the warming CO2 contributes. Here is a graph of the various forcings that influence climate (methane is CH4, right above CO2).
This is not to say methane can be ignored - reducing methane levels is definitely a goal to pursue. The good news is since the early 1990's, the trend in increasing methane has slowed down and even leveled off in the last few years (Dlugokencky 2003).
Last updated on 9 July 2010 by John Cook.