Global Geological And Climatic Events

Permafrost and the hazards of its Thawing


From UPSC perspective, the following things are important :

Prelims level : Permafrost

Mains level : Paper 1-Permafrost thaw.

The principal reason that led to the recent 20,000-tonne oil leak at an Arctic region power plant in Russia that is now being recognised is the sinking of ground surface due to permafrost thaw.

Try this question from Mains 2017:
Q. What is Cryosphere? How does the Cryosphere affect global climate?

What is Permafrost?

  • 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.

Where are they found?

  • These grounds are known to be below 22 per cent of the land surface on Earth, mostly in polar zones and regions with high mountains.
  • They are spread across 55 per cent of the landmass in Russia and Canada, 85 per cent 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.

How climate change is eating away at these grounds?

  • The Earth’s polar and high altitude regions — its principal permafrost reservoirs — are the most threatened by climate change.
  • Arctic regions are warming twice as fast compared to the rest of the planet, its current rate of temperature change being the highest in 2,000 years.
  • 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.
  • This degradation is expected to further aggravate as the climate gets warmer, putting at risk 40 per cent of the world’s permafrost towards the end of the century– causing disastrous effects.

The threat to infrastructure

  • Thawing permafrost is also ominous for man-made structures overhead.
  • The Russian oil leak occurred recorded temperatures in Siberia at more than 10 degrees Celsius above average, and called them “highly anomalous” for the region where the power plant is located.
  • 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.
  • These changes also threaten the survival of indigenous people, as well as Arctic animals.

A ticking time bomb

  • Beneath its surface, permafrost contains large quantities of organic leftover from thousands of years prior — dead remains of plants, animals, and microorganisms that got frozen before they could rot.
  • It also holds a massive trove of pathogens.
  • When permafrost thaws, microbes start decomposing this carbon matter, releasing greenhouse gases like methane and carbon dioxide.
  • Researchers have estimated that for every 1 degree Celsius rise in temperature, these grounds could release GHGs to the tune of 4-6 years’ of emissions from coal, oil, and natural gas.
  • Along with greenhouse houses, these grounds could also release ancient bacteria and viruses into the atmosphere as they unfreeze.


Also read:

Ambarnaya River Oil spill in Russia

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