10/06/2020 - Geography

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KEY POINTS

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.

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.

·         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.

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. According to the USA’s National Oceanic and Atmospheric Administration, 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.

The threat to infrastructure

·         Thawing permafrost is also ominous for man-made structures overhead.

·         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.

·         Soil subsidence is a major cause for concern in Siberia, where ground levels have collapsed by more than 85 metres in some parts. In Canada and Alaska, the costs of repairing public infrastructure are escalating.

·         As per an Arctic Council report from 2017, melting ice would make infrastructure foundations unable to withstand loads that they were able to during the 1980s — a finding that has been corroborated by the owners of Russia’s oil leak site, who said after the incident that the fuel tank’s supporting pillars had held it in its place “for 30 years without difficulty”.

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.

·         Along with greenhouse houses, 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.

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