Methane, an extreme, short-lived climate forcer (it is 70 times more powerful than CO2 as a greenhouse gas, but breaks down far quicker in the atmosphere) is usually found under the ice on frozen landmasses, or at the bottom of shallow Siberian seas. However, scientists flying over cracks in melting Arctic sea ice in the deep ocean have recently found high levels of methane emerging – a highly unexpected finding. This is particularly worrying, as any warming in the Arctic is bound to lock into feedback loops that further accelerate warming. (more…)