Scientific American reports: Up to a quarter of the permafrost that lies just under the ground surface in Alaska could thaw by the end of the century, releasing long-trapped carbon that could make its way into the atmosphere and exacerbate global warming, a new study finds.

The study, detailed in the journal Remote Sensing of Environment, maps where that near-surface permafrost lies across Alaska in more detail than previous efforts. That detail could help determine where to focus future work and what areas are at risk of other effects of permafrost melt, such as changes to local ecosystems and threats to infrastructure, the study’s authors say.

About one quarter of the land in the Northern Hemisphere is permafrost, or ground that stays frozen for at least two years. Some of it has been in that frozen state for thousands of years, locking up an amount of carbon that is more than double what is currently in the Earth’s atmosphere. But with temperatures in the Arctic rising at twice the rate of the planet as a whole, permafrost across the region is beginning to thaw, releasing that carbon from its icy confines. [Continue reading…]