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Current Affairs

Permafrost and thawing

Date: 10 June 2020 Tags: Climate Change

Issue

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.

 

Background

The thermoelectric plant at Norilsk is built entirely on permafrost, whose weakening over the years due to climate change caused the pillars supporting a fuel tank at the plant to sink, leading to loss of containment on May 29.

 

Details

  • 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 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.

  • While permafrost itself is always frozen, the surface layer that covers it need not be. In Canada and Russia, for example, colourful tundra vegetation carpet over permafrost for thousands of kilometres.

  • 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.

  • 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.

  • 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 that serve more than 3.5 crore people that live in permafrost regions. These changes also threaten the survival of indigenous people, as well as Arctic animals.

  • 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 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.

  • Along with greenhouse houses, these grounds could also release ancient bacteria and viruses into the atmosphere as they unfreeze.