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Methane, is the second most important greenhouse gas in the atmosphere after carbon dioxide, and has been held responsible for dramatic climate changes in the past. Although methane concentration in the atmosphere is small compared to CO₂ (360 ppm), methane’s impact as a greenhouse gas is about 24 times higher. Its atmospheric concentration has increased from 850 ppb before industrialization to a level of 1.7 ppm recently, and it was estimated to contribute ca. 20% of the global warming effect.

Aquatic systems including wetlands, oceans, and lakes supply more than 80% of all natural global methane emissions to the atmosphere. Whereas the ocean generally contributes only a small amount of ~5-20 Tg methane (<2% of the global budget) to the atmosphere per year lakes and other freshwater systems have recently brought into the game as an important player. Although covering a much smaller area of the Earth’s surface compared to the oceans, lakes have been made responsible for 6–16% of the total natural methane emissions (8–48 Tg CH₄ yr ^-1), i.e., much more than oceanic emissions. At Eawag we have several projects that investigate methane emissions from aquatic systems including lakes and reservoirs.

This website gives an overview of the different projects which are conducted in respect to methane.