Methane release in the Arctic could aggravate the effects of climate change to the tune of $60 trillion over coming decades, according to a paper published in the journal Nature.
Governments and industry have expected an economic boon from widespread warming of the Arctic, allowing for the exploitation of new gas and oilfields and enabling faster shipping between Europe and Asia. But the release of a 50-gigatonne reservoir of methane from thawing permafrost under the East Siberian Sea carries a hefty pricetag, say the researchers.
"The global impact of a warming Arctic is an economic timebomb," said Gail Whiteman, an author of the report and professor of sustainability, management and climate change at the Rotterdam School of Management, part of Erasmus University.
"In the absence of climate-change mitigation measures, the model calculates that it would increase mean global climate impacts by $60 trillion," said Chris Hope, a reader in policy modelling at the Cambridge Judge Business School, part of the University of Cambridge.
That approaches the value of the global economy, which was around $70 trillion last year.
Methane is a greenhouse gas usually trapped as methane hydrate in sediment beneath the seabed. As temperatures rise, the hydrate breaks down and methane is released from the seabed, mostly dissolving into the seawater.
But if trapped methane were to break the sea surface and escape into the atmosphere, it could "speed up sea-ice retreat, reduce the reflection of solar energy and accelerate the melting of the Greenland ice sheet," the study said.