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According to a new study, the fire regimes in the Arctic are changing rapidly, with ‘zombie fires’ becoming more frequent in addition to fires occurring in the once-frozen tundra.

Zombie Fire: It is a fire from a previous growing season that can smoulder under the ground which is made up of carbon-rich peat. When the weather warms, the fire can reignite. These are also known as holdover fires.

  • The fires in the Arctic spreading to areas which were formerly fire-resistant is a more worrying feature.
     
  • The tundra is drying up and vegetation there like moss, grass, dwarf shrubs, etc are starting to catch fire.
  • In 2019 and 2020, burning occurred well above the Arctic Circle, a region not normally known to support large wildfires. Wildfires on permafrost in Siberia south of the Arctic are not uncommon.

Reasons:

The reason for this anomaly is that temperatures in winter and spring were warmer than usual during 2019-20.

  • Temperature in Siberia in 2020 had gone through the roof, with the region recording a severe heatwave.
  • Nearly all of this year’s fires inside the Arctic Circle occurred on continuous permafrost, with over half of these burning on ancient carbon-rich peat soils.

 Impact:

  • The fires and record temperatures had the potential of turning the carbon sink into a carbon source and increasing global warming.
     
    • The Arctic region has a cold body of water and permafrost, it naturally acts as a carbon sink. On average it absorbs 58 megatons of CO2 a year in its cold water.
    • Soils in areas of permafrost contain twice as much carbon as there is currently in the atmosphere.
    • As the climate and permafrost soils have warmed, microbes have started to break down this organic carbon, which has been frozen and fixed in the permafrost. That has led to a rise in land emissions of CO2 and methane.
    • Also there will be less absorption of carbon by water with rising temperature.
  • It will be a feedback loop: As peatlands release more carbon, global warming increases, which thaws more peat and causes more wildfires.

Arctic fires will affect the global climate over the long term depending on what they burnt. That’s because peatlands, unlike boreal forest, do not regrow quickly after a fire, so the carbon released is permanently lost to the atmosphere.