Exceptionally warm ocean temperatures have melted sea ice off Alaska’s coasts far earlier than normal this year, alarming scientists and rural residents worried about the impacts to seals, seabirds and fish they hunt.
The early melting has been "crazy,” said Janet Mitchell of the village of Kivalina in Northwest Alaska.
In early June, a group of hunters from her family traveled more than 50 miles by boat to find bearded seals on the ice. The ice, and the seals that accompany it, should have been just outside the village. But the ice had receded far to the north.
“We didn’t know if we’d have our winter food," she said. “That was scary."
The hunters ran out of gas while bringing home eight seals and a walrus. They called other residents for an emergency fuel delivery, Mitchell said.
In a tweet on Monday, Rick Thoman, a climatologist with the University of Alaska Fairbanks, said, “The northern Bering and southern Chukchi seas are baking."
Sea surface temperatures last week were as high as 9 degrees above normal, reaching into the lower 60s, he said. The warmest spots are in Kotzebue and Norton sounds, but the unusual heat extends far out into the ocean.
The warmth appears to be weeks ahead of schedule, scientists said.
It’s part of a “positive feedback loop" compounded by climate change. Rising ocean temperatures have led to less sea ice, which leads to warmer ocean temperatures, he said.
The last five years have produced the warmest sea-surface temperatures on record in the region, contributing to record low sea-ice levels.
“The waters are warmer than last year at this time, and that was an extremely warm year,” he said.
Lisa Sheffield Guy, a project manager with the Arctic Research Consortium of the United States, runs an online platform that allows Alaska Native walrus hunters to share tips on the sea ice, weather and hunting.
The need for reporting ended on May 31, the earliest ever. Coastal sea ice had melted so much that it was no longer necessary.
“When we started in 2010, we would go until the last week of June," she said.
A seabird biologist who studied birds on St. Lawrence Island in the Bering Strait region, Guy said she’s worried the warmer temperatures will make it harder for seabirds to find the tiny seafood they eat. The heat might push their prey deeper or away from the area altogether.
The consequences for seabird colonies could be “devastating" if die-offs or low birth rates for some species in recent years continue.
The warmer ocean temperatures come as hunters report large numbers of dead seals off Alaska’s western and northern coasts, Thoman said.
An unusually large number of dead gray whales have also been found off Alaska’s southern coasts, where sea surface temperatures are also unusually high, Thoman said.
Scientists are scrambling to learn what’s causing the wildlife deaths. It’s not known whether the warm water has contributed, Thoman said.
“Certainly it’s all happening at the same time,” he said.
With less sea ice, coastal Alaska communities are unusually warm, said Brian Brettschneider, a UAF climatologist.
Monthly temperature records are being “blown away” in some communities, such as Kotzebue in Northwest Alaska, he said.
In March, the high temperatures were blamed for a large ice shelf breaking from the coast near Nome in March, dragging tethered crab pots with it.
Nick Treinen said he lost two crab pots that had been set on the sea floor, while others lost more.
“It was unprecedented for March,” he said, at least two months ahead of schedule.
The wayward chunk of ice also swept away gold mining equipment, forcing a helicopter rescue for three miners who unsuccessfully tried saving it.
Thoman said the National Oceanic and Atmospheric Administration will conduct an unusually extensive fish survey in the Bering Strait this summer. It could provide clues for possible impacts to valuable fisheries in the Bering Sea.
“We’ll have the results of what this has meant for fish in the Bering Sea, and the potential commercial impacts to fishing,” he said.