Methane's Role in Global Warming
Like emissions of other GHGs, emissions of methane due to human activities (anthropogenic emissions) have increased markedly since pre-industrial times. The global atmospheric concentration of methane has grown from a preindustrial value of about 715 parts per billion (ppb) to 1,782 ppb in 2007 — a nearly 150-percent rise and far above the natural range of the last 650,000 years.1 Global anthropogenic methane emissions are projected to increase nearly 20 percent to 8,522 million metric tons of carbon dioxide equivalent (MMTCO2E) by 2030.2
Of the GHGs emitted as a result of human activities, methane is the second most important GHG after carbon dioxide (CO2), accounting for 14 percent of global GHG emissions in 2005.3 Though methane is emitted into the atmosphere in smaller quantities than CO2, its global warming potential (i.e., the ability of the gas to trap heat in the atmosphere) is 25 times that of CO2, resulting in methane's stronger influence on warming during its 12-year atmospheric life time.
Reducing methane emissions, therefore, can have significant climate change benefits, especially in the near term. In particular, methane reductions can help avoid potential climatic tipping points and reduce environmental impacts, especially in the Arctic. Moreover, of all the short-lived climate forcers, methane has a large reduction potential and cost-effective mitigation technologies are available.4 A 2003 report estimated that achieving a 50-percent reduction in methane emissions from a business-as-usual scenario by 2050 and maintaining those reductions through 2100 could help reduce global temperature on the same scale as similar reductions in CO2 emissions—about 0.55 degrees Celsius.5
For more information on methane science, please visit the U.S. EPA's Methane website . For more information on the importance of methane reduction in mitigating the impact of global warming on the Arctic region, visit the Arctic Council's Arctic Monitoring and Assessment Programme's Technical Report No. 1 .6