Sea ice along Alaska’s northern coast is not lasting as long as it used to. Scientists who studied 27 years of data say this change is becoming clearer over time. The research was done by scientists from the University of Alaska Fairbanks Geophysical Institute and was published in January in the Journal of Geophysical Research Oceans. They studied a special type of ice called landfast ice. Landfast ice is different from other sea ice. It stays attached to the coast. It does not move with wind or ocean currents. This makes it essential for people living near the sea. The new study shows some changes. The ice is forming later each year. It also does not last as long as before. The total area of this ice has become smaller in recent winters. This means there is less stable ice along the coast. The study focused on two Arctic areas: the Chukchi Sea and the Beaufort Sea.
In the Chukchi Sea, landfast ice has been slowly decreasing for many years. In the Beaufort Sea, the ice had stayed fairly stable from the 1970s to the early 2000s. But in recent years, scientists have started to see a clear decline there as well. One of the most significant changes is the shorter ice season. From 1996 to 2023, the landfast ice season became 57 days shorter in the Chukchi Sea. It shrank by 39 days in the Beaufort Sea. This change is mostly happening because the ice is forming later in the year. Even when the air temperature drops below freezing, the ocean stays warmer for longer, which delays ice formation.
In the Chukchi Sea, the ice is also breaking away earlier than before. But in the Beaufort Sea, the ice season is shorter mainly because the ice forms later, not because it melts earlier. Landfast ice is essential for people living there. It gives them a safe path to travel. They use it to reach hunting and fishing areas. When the ice season becomes shorter, travel becomes more dangerous. It also makes hunting and fishing harder and less predictable.
The ice is also important for industry. Oil and gas companies use it to make temporary ice roads. These roads connect offshore and coastal areas in winter. When the ice is less stable, it is harder to build and use these roads. Another key benefit of landfast ice is that it protects the coastline. Because it stays in place, it acts like a barrier against strong ocean waves. It also helps river water spread out into the sea more gradually. Coastlines face stronger wave damage when there is less of this ice.
Scientists noted that the Beaufort Sea’s landfast ice no longer reaches as far into the ocean. In the past, it could extend into deeper waters. Now, it stays closer to the shore. One possible reason for this change is that Arctic sea ice is getting thinner over time. Thicker ice can form strong ridges that reach the seafloor and help keep the ice steady. However, thinner ice does not form these strong anchors as often, so it is less stable and can move more easily.
Researchers say they are seeing fewer of these grounded ice ridges forming. However, they are not yet sure why this phenomenon is happening. It could be that the ridges are not forming at all or that they are not growing large enough after they start forming. Scientists believe more research is required to fully comprehend these changes. What is clear is that landfast ice is declining along with the rest of the Arctic ice. These changes are not just environmental; they are directly affecting the lives of people and the stability of coastal regions.
