Why is Alaska's coastal ice vanishing so fast? 27 years of data tell the story

Vanishing coastal ice

The ice that has protected Alaska's coasts is disappearing — far faster than expected.

Professor Andrew Mahoney at the University of Alaska Fairbanks led a team analysing 27 years of satellite data from 1996 to 2023. The focus: landfast ice in the Chukchi and Beaufort seas — ice anchored to the shore.

An ice season 57 days shorter

In the Chukchi Sea the landfast ice season shrank by 57 days. In the Beaufort Sea, 39 days. The main cause is later ice formation in autumn, rather than earlier spring melt.

The Beaufort Sea's share of total US outer continental shelf landfast ice fell from 3.8% to 2%. Ice no longer reaches waters 20 metres deep in some areas.

What the researcher says

Landfast ice is the ice that is used by people. It has a much more immediate connection with humans.

— Andrew Mahoney (University of Alaska Fairbanks, Professor)

The shortening of the landfast ice season may matter even more for coastal communities than any loss of ice area, because it leaves shorelines more exposed to waves and makes hunting conditions much more uncertain.

— Andrew Mahoney

Landfast ice is diminishing with the rest of the ice in the Arctic. In some ways it follows the same trends, but we are also seeing new changes.

— Andrew Mahoney

What the ice was protecting

Landfast ice is more than frozen sea surface. It shields coasts from erosion, serves as a platform for Indigenous hunting and travel, and provides habitat for marine mammals. That ice shrinks year by year. Twenty-seven years of data make the fact undeniable.

For more on sea level impacts, see 'Africa's coastal sea level rise threatens 200 million lives.'

A note from the author: '57 days in the Chukchi Sea, 39 in the Beaufort.' I have been thinking about the weight of those numbers.

This ice also serves as a platform for hunting and travel. It is not just frozen water. The pace at which this foundation is disappearing may be more serious than the numbers alone suggest.