Arctic permafrost is now a net source of major greenhouse gases

Areas of permanently frozen ground in northern regions are now emitting more carbon into the atmosphere than they absorb, causing the planet to heat even further, according to the first Arctic-wide estimate of all three major greenhouse gases.

Frozen ground, or permafrost, which underlies 15 per cent of the northern hemisphere and contains twice as much carbon as the atmosphere, has shrunk in area by an estimated 7 per cent in 50 years as it thaws. Recent research suggests the thaw will slow…