The release of methane and carbon dioxide from thawing permafrost will accelerate global warming and add up to $70 trillion 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 that hits a surface is reflected without being absorbed – based on the most advanced computer models of what is likely to happen in the Arctic as temperatures rise. It shows how destabilized natural systems will worsen the problem caused by man-made emissions, making it more difficult and expensive to solve. They assessed known stocks of frozen organic matter in the ground up to 3 meters deep at multiple points across the Arctic. These were run through the world’s most advanced simulation software in the US and at the UK Met Office to predict how much gas will be released at different levels of warming. Even with supercomputers, the number crunching took weeks because the vast geography and complex climate interactions of the Arctic throw up multiple variables. The researchers then applied previous economic impact models to assess the likely costs. Permafrost melt is the main concern because of all the carbon trapped in the frozen ground. “On the current trajectory of at least 3C of warming by the end of the century, melting permafrost is expected to discharge up to 280 gigatons of carbon dioxide and 3 gigatons of methane, which has a climate effect that is 10 to 20 times stronger than CO2,” the report says.
“This would increase the global climate-driven impacts by by $70 trillion between now and 2300. This is 10 times higher than the projected benefits from a melting Arctic, such as easier navigation for ships and access to minerals, says the paper.”