For thousands of years, permafrost – ground that is frozen for two or more years in a row – has kept dead plant and animal matter locked in the deep-freeze beneath the tundra. These ancient remnants total up to an estimated 1,600 billion tonnes of organic carbon, almost twice as much as currently found in the Earth’s atmosphere.
Among those gases is methane, a gas up to 34 times more potent than carbon dioxide (CO2) at trapping heat in Earth’s atmosphere during a 100-year period. Across 20 years, it can be 86 times more potent. Then there’s nitrous oxide – its warming potential roughly 300 times more than CO2 across a 100-year timescale.