According to the
EPA,
human related activity accounts for 70 percent of
global emissions of
methane. (
1994 report using
1990 data). Globally, these human influenced sources of methane are:
China, the former Soviet Union, India, the United States, and Brazil are estimated to be responsible for almost half of all anthropogenic methane emissions, although each varies in its method of production. In China, methane comes from coal and rice production. The former Soviet Union (mainly Russia) emits most of its methane from natural gas and oil systems. In India, it's rice and livestock, but in the United States most of the methane comes from landfills.
Wetlands, gas hydrates, permafrost, termites, oceans, soil, and wildfires are natural sources of methane emissions.