Alaska's Marine Ecosystem Experienced 'Sudden and Dramatic Shift' Due to Climate Change, Say Scientists

Environmental changes linked to climate change are having a swift and possibly irreversible effect on Alaska's marine environment, say scientists.

A paper published in Nature Climate Change has recorded environmental and biological changes affecting the region over the last few years—as well as the impacts those changes will have on humans, from subsistence farming to large-scale commercial fishing operations.

Scientists say 2017 showed signs of "a sudden and dramatic shift," with ecological changes that marked a departure from preceding years.

According to the study: "Many changes persisted in 2018 and even into 2019, suggesting that 2017 was not a passing oddity of brief consequence to social-ecological systems, but a sign of what is to come."

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An Alaskan Harbor Seal in the middle of a yawn.
Exceptionally warm years from 2017 to 2019 have had a dramatic affect on the Arctic's ecosystem and wildlife—like the harbor seal, pictured here mid-yawn. NaturesThumbPrint/iStock

"The Arctic can change even faster than we thought," co-author Henry Huntingdon, an independent researcher on Arctic Ocean conservation for Ocean Conservancy, told Newsweek. "This kind of surprise can probably happen elsewhere, too, so we can't assume we have the time we might want to adjust."

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The life-cycle of the Chukchi and Bering Seas is driven by seasonal fluctuations in sea ice and water temperatures. Whales, walruses and other species move southwards into the Bering Sea in the winter months when the water freezes over. Snow melt and algae growth in the spring allows marine species to flourish in summer.

However, as global average temperatures rise, the area is seeing less ice and more heat than it has in the past—and 2017 was a particularly dramatic time, signaling a "sharp departure" from previous years. According to the study's authors, sea ice coverage was significantly below the norm in 2017 and in the years since, while temperatures have exceeded what is typically expected.

These balmier seasons have encouraged animals to migrate to the seas prematurely and stay longer. Bowhead whales were showing up near Utqiaġvik, Alaska, almost a month earlier than usual and some forewent their typical winter migration to a spot south of Anadyr Strait, the Bering Sea. Instead, choosing to stay in Chukchi.

Spotted seal pups were less healthy, appearing thinner and smaller than normal. Very few ribbon seal pups appeared to have been born at all, while 280 seal carcasses were found in the spring and summer of 2018—roughly five times the annual average between 2014 and 2017.

Meanwhile, warmer temperatures are encouraging subarctic species like the Pacific cod to move further north, placing added pressure on the animals that already live there as they compete for limited food supplies.

Pacific Cod during the Paris international agricultural fair
Species like the Pacific cod could be swimming further northwards as water temperatures rise and sea ice melts. LOIC VENANCE / AFP/Getty

The study's authors say these changes have "the potential to fundamentally reconfigure the Pacific Arctic marine food web" and they are already starting to have an effect on local communities. Opportunities to hunt marine mammals in the spring have shrunk thanks to lower levels of sea ice. Additional whaling is able to take place in the fall for the same reason.

"It is possible that 2017 marked the crossing of a threshold that precludes return to the system state that was common just a decade ago," write the study's authors.

Why 2017? No one knows. "There was nothing in particular that hinted at what would happen in 2017," said Huntingdon. "It would of course be helpful if we could identify some indicators that change is about to accelerate, but we have not been able to find those indicators."

They expect the sea-ice season to further shorten, while levels of sea-ice coverage continue to shrink. Water temperatures are expected to get warmer and stay warmer for longer.

However, it's not just the North Pacific. "Social-ecological systems worldwide are facing similar pressures from changing physical conditions, with implications that are increasingly uncertain as transformation propagates through the food web and to human outcomes."

The study's authors call for more research to better understand how these systems are changing—"perhaps in time for more effective response or adaptation, even if prevention may no longer be possible."

Huntingdon hopes the research will prompt greater awareness for how we may be "caught by surprise" as the world's climate continues to warm.

The article has been updated to include comments from Henry Huntingdon.

Alaska's Marine Ecosystem Experienced 'Sudden and Dramatic Shift' Due to Climate Change, Say Scientists | Tech & Science