Arctic Landfast Sea Ice Declining Across Alaska's Coasts

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According to 27 years of data analyzed by University of Alaska Fairbanks scientists, sea ice is sticking to Alaska's northern coast for less time each year. The landfast ice, which stays attached to the shoreline instead of drifting, has also covered less total area in recent winters. The researchers found the landfast ice season has shrunk mostly due to the ice forming later in the fall, as the ocean stays warmer longer.

Why it matters

Landfast sea ice is critical for coastal communities, who rely on the stable ice to travel to hunting and fishing areas, and for the oil and gas industry to build seasonal ice roads. The decline in landfast ice leaves shorelines more exposed to waves and makes hunting conditions more uncertain for local residents.

The details

The new assessment, led by UAF research professor Andrew Mahoney, found that the extent of Beaufort Sea landfast sea ice has begun to decline in recent years after remaining relatively stable between the 1970s and early 2000s. The landfast ice season has shrunk by 57 days in the Chukchi Sea and 39 days in the Beaufort Sea since 1996. This is due to later ice attachment in the fall, and in the Chukchi, earlier ice detachment in the spring as well. The researchers speculate the recent decline in Beaufort landfast ice is related to the overall thinning of Arctic sea ice, resulting in fewer grounded ice ridges that can anchor the ice to the seafloor.

• From 1996-2023, the landfast ice season has shortened by 57 days in the Chukchi Sea and 39 days in the Beaufort Sea.
• The total percentage of landfast sea ice on the U.S. Outer Continental Shelf decreased from 3.8% in the first nine years of the 27-year record to 2% in the final nine years, 2014–2023.

What they’re saying

What’s next

Additional research is needed to better understand why grounded ice ridges, which help anchor the landfast ice, are not forming as they once did in the Beaufort Sea.