Melting permafrost altering Arctic landscape, study says
WASHINGTON — The Arctic is undergoing a profound, rapid and unmitigated shift into a new climate state, one that is greener, features far less ice, and is a net source of greenhouse gas emissions from melting permafrost, according to a major new federal assessment of the region released Tuesday.
The consequences of these climate shifts will be felt far outside the Arctic in the form of altered weather patterns, increased greenhouse gas emissions, and rising sea levels from the melting Greenland ice sheet and mountain glaciers.
The findings are contained in the 2019 “Arctic Report Card,” a major federal assessment of climate change trends and impacts throughout the region. The study paints an ominous picture of a region lurching to an entirely new and unfamiliar climate state.
“A lot of people think of the Arctic as being a faraway place, but the loss of ice is affecting people now — it’s changing peoples’ lives,” said Don Perovich, a Dartmouth College geophysicist who contributed to the report.
The Bering Sea, which lies between Alaska and Russia, is one of the world’s two most productive fisheries. But the Arctic region is warming more than twice as fast as the rest of the planet, the report found.
The past two years saw record low levels of sea ice — frozen seawater — floating on the Bering Sea during winter, the report found. And the habitats of fish on which commercial fisheries and indigenous groups depend have shifted northward, according to the report released at the annual meeting of the American Geophysical Union.
“Fishing industries are built around the assumption that fish will be in a certain place at a certain time, but that’s changing in response to a rapidly changing Arctic,” said Waleed Abdalati, an environmental scientist at the University of ColoradoBoulder who was not part of the report.
For the first time, the “Arctic Report Card” includes observations from indigenous groups who hunt and fish in the region.
“We look for the return of the sea ice every fall season,” wrote 10 representatives of the region’s more than 70 indigenous communities. “The ice provides access to seals, whales, walrus, fish, crabs and other marine life for our subsistence harvests.”
Especially noteworthy is the report’s conclusion that the Arctic may have already turned into a net emitter of planet-warming carbon emissions due to thawing permafrost, which would only accelerate global warming. Permafrost is the carbon-rich frozen soil that covers 24% of Northern Hemisphere land area, encompassing vast stretches of territory across Alaska, Canada, Siberia and Greenland.
There has been concern in the scientific community that the 1,460 to 1,600 billion metric tons of organic carbon stored in frozen Arctic soils, which amounts to nearly twice as much greenhouse gases than what is contained in the atmosphere, could be released as the permafrost melts.
Meanwhile, a new scientific paper in the journal Nature found that the melting of Greenland’s ice sheet has accelerated. The melting is now seven times faster than in the 1990s.