Glacier melting in Alaska is accelerating faster than expected

2 Jul. () –

Glacier melting on a major Alaskan ice field has accelerated and may reach an irreversible turning point earlier than expected.

New research, led by scientists at Newcastle University, has found that glacier loss in the Juneau Icefieldwhich straddles the border between Alaska and British Columbia, Canada, has increased dramatically since 2010.

The team, which also included universities from the UK, US and Europe, analyzed records dating back to 1770 and identified three distinct periods during which the ice field volume changed.

They found that glacier volume loss remained fairly constant between 1770 and 1979, at between 0.65 and 1.01 km3 per year, increasing to 3.08-3.72 km3 per year between 1979 and 2010. Between 2010 and 2020 there was a sharp acceleration when the rate of ice loss doubled, reaching 5.91 km3 per year.

In particular, the research, published in Nature Communicationsfound that glacier surface shrinkage rates across the entire ice field were five times faster between 2015 and 2019 relative to the 1948–1979 period.

Overall, the total ice loss on the Juneau Ice Field between 1770 and 2020 (315.3 +/- 237.5 km3) amounted to just under a quarter of the original ice volume.

The increased rate of glacier thinning has also been accompanied by increased glacier fragmentation. The team mapped a dramatic increase in disconnections, where the lower parts of a glacier separate from the upper parts.

In addition, 100% of the glaciers mapped in 2019 have retreated relative to their position in 1770, and 108 glaciers have disappeared completely.

Study leader Dr Bethan Davies, a senior lecturer at Newcastle University, said: “It is incredibly worrying “Our research has found a rapid acceleration since the beginning of the 21st century in the rate of glacier loss on the Juneau Icefield. The Alaskan ice fields, which are predominantly flat plateau ice fields, are particularly vulnerable to accelerated melting as the climate warms because ice loss occurs across the entire surface, meaning a much larger area is affected.”

Alaska contains some of the largest plateau ice fields in the world and its melting is a major contributor to current sea level rise. Researchers believe the processes they observed in Juneau They will probably affect other similar ice fields. elsewhere in Alaska and Canada, as well as Greenland, Norway, and other high Arctic locations.