The Arctic, a region of the world particularly subject to the effects of global warming, now emits more carbon dioxide (CO2) that it is storing it due in particular to the increase in fires, according to a reference American report published Tuesday.
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“The Arctic tundra, which is experiencing warming and an increase in wildfires, now emits more carbon than it stores,” explains Rick Spinrad, the head of the US National Atmospheric and Oceanic Observation Agency (NOAA). ), which publishes this report.
This will “worsen the effects of climate change,” he warns, adding that it is “one more sign predicted by scientists of the consequences of inadequately reducing fossil fuel pollution.”
“What is happening in the Arctic is not confined to the Arctic,” Anna Virkkala, a researcher at the Woodwell Climate Research Center and co-author of the report, told AFP.
This region which includes the North Pole “plays an important role in the global climate system due to the enormous carbon reservoirs” present in its soils, she explains.
The Arctic is notably composed of tundra, an ecological environment made up of low vegetation and permafrost, also called permafrost, frozen ground which contains double the amount of CO2 present in the atmosphere and triple what has been emitted by human activities since 1850.
However, in recent decades, under the effect of global warming, tundra fires have continued to increase and reached a record in 2023, notes NOAA.
By burning vegetation, these fires release carbon dioxide into the atmosphere. But they also alter the insulating layers of the ground, accelerating the long-term thawing of permafrost, which results in the emission of carbon dioxide and methane, two of the main heat-trapping gases in the atmosphere.
AFP
Amplification
The record fire season experienced by Canada in 2023 led to the emission of “nearly 400 million tonnes of carbon dioxide”, points out Brendan Rogers, co-author of the report, or “more than the annual emissions of all other countries, except China, the United States, India and Russia.
And 2024 comes in second place in terms of emissions linked to fires occurring north of the Arctic Circle, the agency specifies on its site.
Furthermore, according to the NOAA report, based on observations carried out between 2001 and 2020, the temperatures recorded on the surface of the Arctic, but also those at least 15 meters deep, in the permafrost, have continued to increase in recent years.
The Arctic is affected by a phenomenon called “amplification”, which means that it is warming faster than mid-latitudes. This mechanism is due to many factors, such as the loss of snow cover and sea ice, or the warming of the oceans.
If the increase in temperatures linked to global warming stimulates the productivity and growth of plants, which absorb carbon dioxide, it also causes the thawing of permafrost.
“Alarming”
The fact that the tundra now releases more CO2 that it does not store any is “an alarming warning sign”, reacted Brenda Ekwurzel, climatologist from the American NGO Union of Concerned Scientists.
“Once reached, many of these thresholds of negative impacts on ecosystems are irreversible,” she warned.
“Permafrost emissions are not going to surpass emissions from fossil fuels, but they constitute an important layer, and we must therefore take them into account,” emphasizes Brendan Rogers.
In addition to becoming warmer, the Arctic is also becoming wetter, NOAA also documents, with the summer of 2024 having been the wettest on record.
This trend is accelerating coastal erosion, threatening indigenous communities that rely on stable ice and traditional hunting practices.
