"'Tipping elements' in the rapidly warming Arctic may add trillions of dollars to the long-term costs of climate change, a new study suggests.
As temperatures rise, thawing permafrost may release large amounts of carbon dioxide and methane into the atmosphere, causing even more warming. At the same time, the disappearance of snow and ice cover — bright, reflective surfaces that help to beam sunlight away from the planet — will cause the Earth to absorb even more heat.
The result is to worsen the progression of climate change even further.
The problem is that these processes haven't been adequately accounted for, if at all, in many of the models scientists use to make projections about the future. That means previous calculations may be underestimating the damages associated with long-term warming."