As the Arctic experiences profound changes due to climate alterations, a new pattern of wildfires referred to as ‘zombie fires’ has begun to emerge. The research shows an alarming increase in the frequency of these fires, including in territories previously considered immune, such as the cold, barren tundra.
The nature of ‘Zombie Fires’
Zombie Fires have been identified as underground fires from previous growing seasons that can sustain themselves under carbon-rich peat soils and reignite with warmer temperatures. This phenomenon, also known as “holdover fire”, comes with a disturbing expansion: fires are now occurring in regions previously resistant to them. The tundra – a cold, treeless region mostly located in the north of the Arctic Circle or above the timberline on mountains – is experiencing desiccation, with its vegetation such as moss, grass, and dwarf shrubs catching fire. This trend was particularly evident in 2019 and 2020 when burning was observed significantly above the Arctic Circle, where large wildfires are not typically seen.
Causes of the Changing Fire Pattern
The shift in wildfire patterns is largely attributed to warming temperatures. In Siberia, 2020 witnessed higher winter and spring temperatures than usual, resulting in a severe heatwave. This year’s fires struck predominantly in areas of continuous permafrost, with over half igniting on ancient carbon-rich peat soils.
The Impact on the Global Climate
These changes bring serious implications for global warming. The Arctic, characterized by its cold water bodies and permafrost, naturally serves as a carbon sink, absorbing around 58 megatons of CO2 annually. However, the rising temperatures and burning of peatlands are threatening to turn this carbon sink into a significant carbon source. As microbes start to decompose the organic carbon in the warmed permafrost soils, there is an increase in CO2 and methane emissions. Since peatlands are slow to regrow after a fire, the carbon released cannot be reabsorbed, leading to a permanently increased amount of carbon in the atmosphere.
Understanding Arctic Permafrost
Arctic Permafrost is ground that stays entirely frozen at 0 degrees Celsius or below for at least two consecutive years. It‘s made up of various components such as rock, sediments, sand, dead plant, animal matter, soil, and different degrees of ice. Predominantly found near the polar zones and regions with high mountains, it contains substantial amounts of carbon and other greenhouse gases, which can be released via combustion. With the Arctic region warming twice as fast as the rest of the planet, permafrost is under significant threat from climate change.
Moving Forward
The rapidly changing fire dynamics in the Arctic necessitate a thorough understanding of the patterns and effects of these fires. Indigenous peoples of the Arctic have traditionally possessed significant knowledge about handling fires, from which the global community could potentially learn. It is urgent to develop and implement new permafrost and peat-sensitive firefighting approaches, calling for international collaboration, investment, and proactive measures.
