What are the main sources of methane emissions?

There are both natural and human sources of methane emissions. The main natural sources include wetlands, termites and the oceans. Natural sources create 36% of methane emissions. Important human sources come from landfills, livestock farming, as well as the production, transportation and use of fossil fuels. Human-related sources create the majority of methane emissions, accounting for 64% of the total.

Methane levels have more than doubled over the last 150 years because of human activities like fossil fuel use and intensive farming.Before the Industrial Revolution, the atmospheric concentration of methane was maintained in a safe range by natural sinks.

But for a long time now human activities have been creating methane emissions much more rapidly than the Earth can remove them, increasing global methane levels. During the last 800,000 years, methane concentrations naturally varied between 350-800 ppb but since the Industrial Revolution, methane levels have become much higher and are now 2.5 times larger.