This past summer was the hottest on record in the Arctic, which is warming nearly four times faster than any other location on the planet. And the symptoms of that warming laid bare a rapidly changing region that in many ways barely resembles what it once was.
Key data points show that the Arctic continues to become less icy, wetter and greener, according to a report card released by the National Oceanic and Atmospheric Administration on Tuesday. The trends, all linked to a warming climate, have been observed for decades.
And they played out in dramatic ways this summer: Out-of-control wildfires forced entire communities to evacuate. A river surged from its banks and into homes because of dramatic glacial thinning. Near the peak of Greenland’s ice sheet, more than 10,000 feet above sea level, temperatures rose above freezing for only the fifth time on record.
Even amid rapid change, variability of weather patterns meant a few parts of the Arctic still exhibited some of the frigid norms of the past. For example, sea ice persisted for much of the summer in the East Siberian Sea, and a colder-than-normal spring slowed the melt of sea ice and snow cover in Alaska.
But the report, by 82 authors in 13 countries, makes clear that the Arctic continues to change, with the past 17 years accounting for the 17 smallest annual minimum sea ice covers in the 45-year satellite record. This year, sea ice cover ranked sixth-smallest, amid summer temperatures that were the Arctic’s hottest on record and a year that ranks sixth-warmest.
“Extreme weather and climate events during the past year in the Arctic and elsewhere have brought unambiguous, climate change-supercharged impacts to people and ecosystems,” the report said.
The report documented changes playing out in dramatic ways as observed by scientists and Native communities — some predictable, but others counterintuitive.
Ships could move freely
The Northwest Passage, which allows ships to pass between the Atlantic and Pacific oceans through the Canadian archipelago, was relatively ice-free by late August. Ice extent along the passage was among the lowest ever observed via satellite. The Northern Sea Route, which runs along Russia’s northern coast, was slower to open to ships, but a path of open water cleared up by late August.
The Northwest Passage has long been an object of fascination as a means to dramatically reduce shipping distances and costs, and especially since 2007, when dramatic melting first opened it up. Recent research found that year brought a retreat of Arctic ice that was so dramatic, it marked a fundamental and irreversible change.
Salmon populations neared record lows and highs
Chinook and chum salmon populations in western Alaska — which have been collapsing for decades, devastating communities that rely on the fishery — were well below average in 2023, though they rebounded slightly from a record low in 2022. Abnormal and enduring summer heat across Canada meant that waterways such as the Yukon River became too warm for a species that thrives in frigid waters.
Sockeye salmon, on the other hand, surged to record high abundance in southwestern Alaska’s Bristol Bay in 2022, the most recent year for which data was available for the report. The warming climate means the fish are heading out to sea sooner, rather than living in upstream lakes and rivers until they mature.
The diverging salmon fortunes show that, when analyzing how climate change will affect complex ecologies, it’s impossible “to take a paintbrush and broad brush,” said Rick Thoman, lead editor for this year’s report card and a climate specialist at the International Arctic Research Center at the University of Alaska at Fairbanks.
The two species “have different life histories,” he said. “The details matter a lot.”
Ice losses caused severe flooding
When a torrent of water flowed down the Mendenhall River toward Juneau, Alaska, in August, sweeping away homes and dramatically eroding shorelines, it was “a direct result of dramatic glacial thinning over the past 20 years,” the report found.
Floods have been occurring annually as meltwater from Mendenhall Glacier flows past an ice dam, but this one was far larger than any other ever seen.
Ice melted near the peak of Greenland’s ice sheet
Temperatures at Summit Station, a research outpost in central Greenland, neared 33 degrees June 26. It was only the fifth time temperatures at the station rose above freezing in 34 years of observations. In the fall months, Summit Station’s average temperature was about 10 degrees below zero — more than 13 degrees balmier than normal and a record high.
An increase in snowfall across much of Greenland (another symptom of a warming Arctic climate) offset some ice losses this year, but they were still dramatic. At one site in southern Greenland, the ice sheet surface lowered by nearly 16 inches during a single week in June.
Fires forced thousands to evacuate
It was Canada’s worst wildfire season on record, and by a wide margin. The largest of those fires spread across the Northwest Territories, requiring residents of Yellowknife and other communities to evacuate as a precaution, for weeks at a time.
More than 90 percent of the 11 million acres that burned across Canada through the end of October was in the Northwest Territories, according to the report. Data that the European Union’s Copernicus Climate Change Service released Tuesday showed that Canada accounted for 23 percent of global wildfire carbon emissions this year.
“Wildfire in the Arctic and sub-Arctic boreal forest is a natural part of the ecosystem, but the extent and intensity of fires has likely changed over time, in part due to changing human activity and recent variations in wildfire management practices,” the NOAA report said.
NOAA Administrator Rick Spinrad said the report’s findings should spur on efforts to slow the rise in global temperatures, the product of a buildup of fossil fuel emissions in the atmosphere.
“The time for action is now,” Spinrad said at a news conference at the American Geophysical Union’s annual meeting in San Francisco. “Climate change has already altered ecosystems in substantial ways.”
Source : Washington Post