Earth System Trend
UNIT: Parts per billion
Methane is a greenhouse gas that is about 21 times more potent than carbon dioxide over 100 years. Since the start of the Industrial Revolution, methane in the atmosphere has more than doubled from around 750 parts per billion to about 1850 parts per billion in 2010. In the last decade, the rate of increase has slowed. This may be due to short-term changes in natural sources and sinks brought about by higher temperatures and changing rainfall patterns.
Graph Caption: Methane from firn and ice-core records (Law Dome, Antarctica) and Cape Grim, Australia (deseasonalised flask and instrumental records); spline fit.
Source: D. Etheridge CSIRO, Australia; MacFarling Meure et al. 2004 and 2006; Langenfelds et al., 2011.