Frequently asked questions

How much does methane contribute to greenhouse gas emissions

Methane (CH₄) is the second most prevalent greenhouse gas emitted from human activities. In 2014, CH₄ accounted for about 10.6% of all U.S. greenhouse gas emissions from human activities.

Methane is emitted by natural sources such as wetlands, as well as human activities such as leakage from landfill and the raising of livestock. Natural processes in soil and chemical reactions in the atmosphere help remove CH₄ from the atmosphere.

Methane's lifetime in the atmosphere is much shorter than carbon dioxide (CO₂), but CH₄ is more efficient at trapping radiation than CO₂. On a weight basis the comparative impact of CH₄ on climate change is more than 25 times greater than CO₂ over a 100-year period.