The Arctic tundra is undergoing a profound transformation, shifting from a long-standing carbon sink to a net source of carbon dioxide emissions.

This is primarily due to increasing wildfires according to the U.S. National Oceanic and Atmospheric Administration (NOAA).

NOAA’s 2024 Arctic Report Card highlights this alarming change, noting that 2023 saw the second-warmest annual surface air temperatures in the Arctic since records began in 1900.

“Our observations now show that the Arctic tundra, which is experiencing warming and increased wildfire, is now emitting more carbon than it stores, which will worsen climate change impacts,” said Rick Spinrad, a Noaa administrator.

The Arctic has been warming faster than the global average for 11 consecutive years and is now heating up at up to four times the global rate.

This rapid warming has a dual impact. On one hand, it enhances plant growth, which absorbs carbon dioxide. On the other, it accelerates permafrost thaw, releasing carbon stored in frozen soil. As permafrost thaws, microbial activity decomposes organic material, emitting carbon dioxide and methane—both potent greenhouse gases.

“We need accurate, holistic and comprehensive knowledge of how climate changes will affect the amount of carbon the Arctic is taking up and storing, and how much it’s releasing back into the atmosphere, in order to effectively address this crisis,” said Dr Sue Natali, a scientist at the Woodwell Center who contributed to the research. “This report represents a critical step toward quantifying these emissions at scale.”

Human-driven climate change is also intensifying Arctic wildfires, which have grown in area, intensity, and carbon emissions. These fires not only release carbon by burning vegetation and soil but also remove insulating soil layers, further accelerating permafrost thaw and associated emissions.

“In recent years, we’ve seen how increasing fire activity from climate change threatens both communities and the carbon stored in permafrost, but now we’re beginning to be able to measure the cumulative impact to the atmosphere, and it’s significant,” said Dr Brendan Rogers, Woodwell Climate scientist and report contributor.

Since 2003, circumpolar wildfires have released an average of 207 million tons of carbon annually. Additionally, Arctic terrestrial ecosystems remain a consistent source of methane emissions, compounding the region’s contribution to global warming.

The report underscores the urgency of addressing climate change as the Arctic transitions into a significant contributor to atmospheric carbon, with cascading impacts on global climate systems.

“The climate catastrophe we’re seeing in the Arctic is already bringing consequences for communities around the world,” said Brenda Ekwurzel, a climate scientist at the Union of Concerned Scientists.

“The alarming harbinger of a net carbon source being unleashed sooner rather than later doesn’t bode well. Once reached, many of these thresholds of adverse impacts on ecosystems cannot be reversed.”