Villagers harvest ice from a local lake near the settlement of Oy, about 70 km south of Yakutsk, Russia, with the air temperature around minus 41 degrees Celsius in November 2018 (Mladen ANTONOV)
Mladen ANTONOV/AFP/AFP PHOTO
By AFP - Agence France Presse
Sinking at the source: The Arctic tundra emits more carbon than it absorbs
Issam AHMED
After trapping carbon dioxide in its frozen soil for millennia, the Arctic tundra is undergoing a dramatic transformation, driven by frequent forest fires that are turning it into a net source of carbon dioxide emissions, a US agency reported on Tuesday.
This radical change is detailed in the National Oceanic and Atmospheric Administration's Arctic Report Card 2024, which revealed that annual air temperatures at the Arctic surface this year were the second warmest ever recorded since 1900.
“Our observations now show that the Arctic tundra, which is experiencing warming and increased forest fires, is emitting more carbon than it stores, which will exacerbate the impacts of climate change,” said NOAA Administrator Rick Spinrad.
“What happens in the Arctic doesn't stay in the Arctic,” Anna Virkkala of the Woodwell Climate Research Center, co-author of the report, told AFP. “We must try to stop anthropogenic climate change as soon as possible so that we can also stop emissions from the Arctic.”
The finding is based on an average of observations recorded from 2001 to 2020.
Climate warming has dual effects on the Arctic. At the same time, as it stimulates plant productivity and growth, which removes carbon dioxide from the atmosphere, it also leads to an increase in the surface air temperature, which causes the permafrost to thaw.
Thawing permafrost releases carbon previously trapped in the frozen ground as carbon dioxide and methane - two potent greenhouse gases - through microbial decomposition.
In 2024, Alaska recorded the second warmest permafrost temperature ever recorded, according to the report.
Human-caused climate change is also intensifying high-latitude forest fires, which have increased the area burned, the intensity, and the associated carbon emissions.
Forest fires not only burn vegetation and soil organic matter, releasing carbon into the atmosphere but also remove insulating layers of soil, accelerating the long-term thawing of permafrost and its associated carbon emissions.
Since 2003, circumpolar emissions from forest fires have averaged 207 million tons of carbon per year, according to NOAA. At the same time, the Arctic's terrestrial ecosystems remain a consistent source of methane.
“Last year, 2023, was the largest fire year ever recorded due to Canadian forest fires, which burned more than twice as much as any other year ever recorded in Canada,” said the report's co-author, Brendan Rogers, during a press conference.
The fires emitted almost 400 million tons of carbon - more than two and a half times the emissions of all other sectors in Canada combined, he added.
Meanwhile, 2024 was ranked as the second-highest year for forest fire emissions within the Arctic Circle.
- 'Alarming omen' -
Asked whether the Arctic's shift from carbon sink to source could be permanent, Rogers said that this is an open question. Although the boreal forests further south still serve as carbon sinks, the northern regions are more worrying.
“The best we can say is that emissions from permafrost are not going to exceed emissions from fossil fuels, but they are a significant layer and therefore need to be taken into account,” he told AFP, adding that aggressively limiting man-made warming could contain the problem to some extent.
Reacting to the news, Brenda Ekwurzel, a climate scientist at the Union of Concerned Scientists, said that “the climate catastrophe we are seeing in the Arctic is already bringing consequences for communities around the world.”
“The alarming harbinger of a net carbon source being released sooner rather than later does not bode well. Once reached, many of these thresholds of adverse impacts on ecosystems cannot be reversed.”
Higher temperatures are also affecting wildlife, and the report found that tundra caribou numbers have declined by 65% in the last two or three decades - with summer heat hampering their movement and survival, as well as changes in winter snow and ice conditions.
Surprisingly, however, Alaska's seal populations remain healthy.
The report found no long-term negative impact on the body condition, age at maturity, pregnancy rates, or pup survival of the four species of ice seals - ringed, bearded, spotted, and ribbon - that inhabit the Bering, Chukchi, and Beaufort seas.
ia/md
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