Maharashtra State PSC Model Paper 3

The correct answer is 1, 2 and 3.

• Permafrost is perennially frozen soil that has been below 0⁰C for at least two years.
  • Permafrost is a condition where the top layer up to a depth of 20-40 cm is completely frozen.
  • This happens in high latitude and altitude regions.
• It's found underneath about 25% of the northern hemisphere, mainly around the Arctic - but also in the Antarctic and Alpine regions.
  • In the northern region of Alaska, the permafrost has been warming at about one-tenth of a degree Celsius per year since the mid-2000s.
• These top soils melt due to global warming which is a great threat as their melt will aggravate the condition of global warming.
  • As permafrost thaws, this carbon is released to the atmosphere in the form of methane, a powerful greenhouse gas.
  • This process leads to more climate change and is an example of a positive feedback loop, which happens when warming causes changes that lead to even more warming.
• As permafrost thaws, it can also cause substantial changes in the local ecosystem, altering the flow of water atop and through the soil, as well as what plant and animal life can thrive in the area.
• It is a part of life in the frigid North Slope, underlying buildings, roads, and other infrastructure.
  • When it thaws, it can cause considerable damage.
  • In Alaska, the warming of the permafrost has been linked to trees toppling, roads buckling, and the development of sinkholes.
• When permafrost melts, the land above it sinks or changes shape.
  • Sinking land can damage buildings and infrastructure such as roads, airports, and water and sewer pipes.
  • It also affects ecosystems.​