Arctic sea ice has been shrinking in recent decades, reaching record lows in summer and winter. A new study shows that the trend also applies to what’s called landfast ice, which has been sticking to Alaska’s northern shores for less time than it used to. Researchers say that can have implications for the climate, resource development and subsistence hunting.
Andrew Mahoney, a research professor at the University of Alaska Fairbanks Geophysical Institute, coauthored the study, which was published in January in the Journal of Geophysical Research: Oceans.
Mahoney said the researchers found that over the past 27 years, landfast ice in Alaska’s Arctic has been forming later, breaking up earlier, and hasn’t been reaching as far offshore.
“So it's sort of shrinking in time, and it's shrinking in space as well,” he said.
Mahoney previously looked at landfast ice in Chukchi and Beaufort seas, in a study published in 2014. At that time, the Chukchi Sea seemed to experience more landfast ice loss, while the Beaufort Sea seemed more stable. This year’s study showed that has changed.
“Now we're starting to see changes in the Beaufort Sea,” Mahoney said. “The Beaufort Sea of today is not the Beaufort Sea of the 1970s. The landfast ice doesn't form as far offshore as it used to.”
Mahoney said that while landfast ice is only a small fraction of the overall ice cover, it is the type of ice most people come in contact with. Indigenous communities have used it for millennia to hunt – like whalers in Utqiagvik in spring.
“A large fraction of the community, at any one time might actually be out on the landfast ice actively whaling,” Mahoney said. “The success of that whale hunt is in part related to how accessible and how stable and safe the landfast ice is.”
Mahoney said that the oil and gas industry also uses landfast ice to build seasonal ice roads to connect to facilities. His team’s study was funded by the federal Bureau of Ocean Energy Management, which is interested in oil and gas development near shore.
Mahoney said coastal communities also lose a shield that protects them from open water when landfast ice breaks up earlier in the spring.
“There's a lot of erosion affecting these communities,” he said. “Most of it happens in the fall, but we could start to see more erosion happening in the springtime if landfast ice keeps breaking up earlier.”
The Arctic has been warming four times faster than the rest of the world. The researchers say the recent landfast ice decline might be related to the overall thinning of Arctic sea ice due to climate change, but more research is needed to better understand the process behind it.
