Natural Methane Emissions in a Changing Arctic - Implications for Climate and Environment

Book excerpt: Natural emissions of methane have received much attention over the last decade due to the documented increase of methane in the atmosphere and high global warming potential relative to CO2. Over the past few decades the Arctic has been warming approximately four times faster than the rest of the planet, driving a pressing need to assess the current and future vulnerability of various natural methane sources. In the Arctic, vast amounts of methane is stored in soils and permafrost or is being generated as permafrost thaw continues. Additionally, there are large stores of methane in Arctic gas hydrates, a solid form of concentrated methane and water, and in numerous settings, including deep-water marine areas, on continental shelves hosting relict subsea permafrost and gas hydrate, in and beneath onshore permafrost, and likely beneath the Greenland Ice Sheet. Continued climate warming is making methane leakage more likely. Even deeper conventional gas reservoirs could leak methane as the overlying permafrost degrades.