Methane is a potent greenhouse gas accounting for about 8 to 11 percent of total U.S. greenhouse gas emissions, with significant contributions globally as well. The largest sources in the U.S. include wood burning in stoves and fireplaces, livestock digestive systems (enteric fermentation), and decomposition in landfills. Methane is more than 28 times as effective as carbon dioxide at trapping heat in the atmosphere over a 100-year period, making it a critical target for climate change mitigation. Despite its shorter atmospheric lifetime of about 7 to 12 years compared to CO2, methane’s strong warming potential means that reducing methane emissions can have a rapid impact on slowing global warming. Agricultural activities, fossil fuel production, and waste management are major anthropogenic sources, while wetlands remain the largest natural source. Because methane breaks down into CO2 and water over time, its long-term climatic impacts also include the effects of these conversion products.
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