Thawing permafrost releases methane and carbon dioxide, greenhouse gases that further exacerbate global warming. Credit: National Park Service Arctic warming will cost trillions of dollars to the global economy over time as the permafrost thaws and the sea ice melts—how many trillions depends on how much the climate warms, and even a half a degree makes a difference, according to a new study. If nations don’t choose more ambitious emission controls, the eventual damage may approach $70 trillion, it concluded. For tens of thousands of years, grasses, other plants and dead animals have become frozen in the Arctic ground, building a carbon storeroom in the permafrost that’s waiting to be unleashed as that ground thaws. It’s considered one of the big tipping points in climate change : as the permafrost thaws, the methane and CO2 it releases will trigger more global warming, which will trigger more thawing. The impacts […]