The release of methane and carbon dioxide from thawing permafrost will accelerate global warming and add up to $70tn (£54tn) to the world’s climate bill, according to the most advanced study yet of the economic consequences of a melting Arctic.

If countries fail to improve on their Paris agreement commitments, this feedback mechanism, combined with a loss of heat-deflecting white ice, will cause a near 5% amplification of global warming and its associated costs, says the paper, which was published on Tuesday in Nature Communications.

The authors say their study is the first to calculate the economic impact of permafrost melt and reduced albedo – a measure of how much light…