Human-related activities include:

• Waste management (landfills): methane is generated in landfills and open dumps as waste decomposes. Landfills are responsible for approximately 34% of human-related methane emissions in the U.S.
• fossil fuel production: methane losses occur during the production, processing, storage, transmission, and distribution of natural gas, oil and coal.
• livestock production: domesticated livestock produce significant amounts of methane during the process of digestion. Significant amounts of methane are also produced as their manure decomposes.
• rice cultivation: methane is produced as organic matter in flooded rice paddies decomposes.

These activities release great quantities of methane into the atmosphere: it is estimated that 60% of global methane emissions are related to human activities.

Methane formula

Natural sources of methane include:

• wetlands: methane-producing bacteria thrive in the moist, low-oxygen, organic-matter rich environments such as wetlands. Wetlands are responsible for roughly three quarters of natural global methane emissions.
• permafrost;
• termites: methane is produced as a part of termites’ digestive process. Termites are responsible for approximately 11% of natural global methane emissions;
• and wildfires.