The study, published in the journal Nature Climate Change, revealed that 40 per cent of Arctic Boreal Zone has become a carbon source, releasing more carbon dioxide into the atmosphere than it absorbs, marking a shift from its role as a carbon sink for millennia.

• The study aligns with findings from the NOAA’s 2024 Arctic Report Card, which highlighted the Arctic tundra’s transition from a carbon sink to a carbon source due to rising temperatures and wildfire activity.

Key Study Findings

• 30% of the Arctic was a net carbon dioxide source during 2001–2020, and 40% when fire emissions were included.
• Fire emissions in the Arctic significantly contribute to the region’s shift into a carbon source.
• Emissions from non-summer months (Sept-May) are higher than the carbon absorbed in the summer months (June-Aug), contributing to the carbon source.
• Contributing Factors to the Shift
  • Longer growing seasons and increased microbial activity have gradually shifted carbon trajectories.
  • Increased frequency and intensity of wildfires have further exacerbated the situation.
  • Permafrost thaw releases vast amounts of carbon stored in the frozen ground as greenhouse gases, accelerating global warming.
• Impact of Greening: 49% of the region is experiencing “greening” due to longer growing seasons and increased vegetation.
  • However, only 12% of the region acts as a net carbon sink annually, as greening is offset by warming temperatures and permafrost thawing.
• Role of Permafrost: Permafrost stores large amounts of carbon in the form of frozen organic material.
  • As permafrost thaws due to rising temperatures, this organic matter is decomposed by microbes, releasing CO2 and methane.

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Arctic Boreal Zone

• The Arctic Boreal Zone, located along the Arctic Circle, is the vast northern ecosystem that spans across 26 million square kilometers, including:
  • Tundra (treeless regions)
  • Boreal forests (taiga)
  • Wetlands
• It is found primarily in regions like Alaska, Canada, Northern Europe, and Siberia.
• Indigenous communities in the Arctic Boreal Zone. 
  • Inuit: The most widespread Arctic coastal people, living from Arctic Russia to Canada to Greenland. The word “Inuit” means “the people” in the Inuit language of Inuktut. 
  • Saami: Live in the circumpolar areas of Finland, Sweden, Norway, and Northwest Russia. 
  • Aleut: Also known as Unangan, lives in Alaska. 
  • Yupik: Also known as Yupiit, lives in Alaska. 

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• Climate Characteristics
  • The region experiences extreme cold with long, harsh winters and short summers.
  • Permafrost (frozen ground) is a defining feature, remaining below 0°C for at least two consecutive years.
  • Short growing season with limited sunlight for vegetation growth, especially in the tundra areas.
  • Cold-adapted species such as reindeer, Arctic foxes, and various migratory bird species inhabit the region.
  • Role as a Carbon Sink: Historically, the Arctic Boreal Zone has acted as a carbon sink, meaning it absorbed more carbon than it emitted.
  • It is known for being soil organic carbon reservoirs.
  • This role was due to:
    • The presence of vast areas of forests and wetlands that sequester carbon through vegetation and soil.
    • Permafrost, which locks up vast amounts of carbon and organic matter.

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