• The thawing of permafrost is the principal reason that led to the recent 20,000-tonne oil leak at an Arctic region power plant in Russia.
  • The thermoelectric plant at Norilsk (3,000 km northeast of Moscow) is built entirely on permafrost, whose weakening over the years due to climate change caused the plant to sink.

What is permafrost?  

While permafrost itself is always frozen, the surface layer that covers it (called the “active layer”) need not be. For example, in Canada and Russia colourful tundra vegetation carpet over permafrost for thousands of kilometres.

  • Permafrost is ground that remains completely frozen at 0 degrees Celsius or below for at least two years. 
  • It is defined solely based on temperature and duration
  • The permanently frozen ground, consisting of soil, sand, and rock held together by ice, is believed to have formed during glacial periods dating several millennia.
  • These grounds are known to be below 22 percent of the land surface on Earth, mostly in polar zones and regions with high mountains. 
  •  Its thickness reduces progressively towards the south, and is affected by a number of other factors, including 
    • the Earth’s interior heat, snow and vegetation cover, presence of water bodies, and topography.
  • They are spread across 
    • 55 percent of the landmass in Russia and Canada, 
    • 85 percent in the US state of Alaska, and possibly the entirety of Antarctica. 
    • In northern Siberia, it forms a layer that is 1,500 m thick; 740 m in northern Alaska. 
    • At lower latitudes, permafrost is found at high altitude locations such as the Alps and the Tibetian plateau.

Impact of climate change on permafrost:

  • The Earth’s polar and high altitude regions - its principal permafrost reservoirs - are the most threatened by climate change. 
  • According to the USA’s National Oceanic and Atmospheric Administration, Arctic regions are warming twice as fast compared to the rest of the planet. 
  • In 2016, Arctic permafrost temperatures were 3.5 degrees Celsius higher than at the beginning of the 20th century.
  • A study has shown that every 1 degree Celsius rise in temperature can degrade up to 39 lakh square kilometre due to thawing. 

How thawing poses risk to the world?

  • Threat to infrastructure: As temperatures rise, the binding ice in permafrost melts, making the ground unstable and leading to massive potholes, landslides, and floods.
    • The sinking effect causes damage to key infrastructure such as roads, railway lines, buildings, power lines and pipelines threatening the survival of indigenous people, as well as Arctic animals.
  • Releasing GHGs: When permafrost thaws, microbes start decomposing carbon matter beneath its surface, releasing greenhouse gases like methane and carbon dioxide.
    • Researchers have estimated that for every 1 degree Celsius rise in average temperature, permafrost grounds could release greenhouse gases to the tune of 4-6 years’ of emissions from coal, oil, and natural gas - becoming a major factor of climate change in themselves.
  • Source of disease: Along with greenhouse gases, these grounds could also release ancient bacteria and viruses into the atmosphere as they unfreeze. 
    • In 2016, a melted 75-year-old anthrax-infected reindeer carcass led to an outbreak of the disease, causing the death of a child and hospitalising 90 people.