BBC - Future - The poisons released by melting Arctic ice

Around 10% of the carbon that does defrost will probably be released as CO2, amounting to 130-150 billion tonnes. That is equivalent to the current rate of total US emissions, every year until 2100. Melting permafrost effectively introduces a new country at number two on the highest emitters list, and one that isn’t accounted for in current IPCC models. “People talk about a carbon bomb,” says Natali. “In geological timescales this is not a slow release. It is a pool of carbon that is locked away and is not accounted for in the carbon budget to keep rises below two degrees (Celsius).”