In the Canadian Arctic, layers of permafrost that scientists expected to remain frozen for at least 70 years have already begun thawing. The once-frozen surface is now sinking and dotted with melt ponds and from above looks a bit like Swiss cheese, satellite images reveal.
“We were astounded that this system responded so quickly to the higher air temperatures,” said Louise Farquharson, a co-author of the study and postdoctoral fellow at the Permafrost Laboratory at the University of Alaska Fairbanks.
Permafrost is ground that remains frozen for at least two years. It underlies about 15% of the unglaciated Northern Hemisphere and serves a critical role in the transfer of carbon from living things to the atmosphere, Farquharson said.