Climate Change Impact on India and World – International Reports, Key Observations, etc.

Places in news: Thwaites Glacier

Note4Students

From UPSC perspective, the following things are important :

Prelims level : Thwaites Glacier

Mains level : Glacial melting and sea level rise

The melting of Antarctica’s Thwaites Glacier – also called the “Doomsday Glacier”– has long been a cause of concern because of its high potential of speeding up the global sea-level rise happening due to climate change.

Thwaites Glacier

  • Called the Thwaites Glacier, it is 120 km wide at its broadest, fast-moving, and melting fast over the years.
  • Because of its size (1.9 lakh square km), it contains enough water to raise the world sea level by more than half a meter.
  • Studies have found the amount of ice flowing out of it has nearly doubled over the past 30 years.
  • Thwaites’s melting already contributes 4% to global sea-level rise each year. It is estimated that it would collapse into the sea in 200-900 years.
  • Thwaites is important for Antarctica as it slows the ice behind it from freely flowing into the ocean. Because of the risk it faces — and poses — Thwaites is often called the Doomsday Glacier.

What have previous studies said?

  • A 2019 study by New York University had discovered a fast-growing cavity in the glacier. Then last year, researchers detected warm water at a vital point below the glacier.
  • The study reported water at just two degrees above freezing point at Thwaites’s “grounding zone” or “grounding line”.
  • The grounding line is the place below a glacier at which the ice transitions between resting fully on bedrock and floating on the ocean as an ice shelf.
  • The location of the line is a pointer to the rate of retreat of a glacier.
  • When glaciers melt and lose weight, they float off the land where they used to be situated. When this happens, the grounding line retreats.
  • That exposes more of a glacier’s underside to seawater, increasing the melting rate resulting in the glacier speeding up, stretching out, and thinning, causing the grounding line to retreat ever further.

What has the new study revealed?

  • The recent Gothenburg study used an uncrewed submarine to go under the Thwaites glacier front to make observations.
  • The submersible called “Ran” measured among other things the strength, temperature, salinity and oxygen content of the ocean currents that go under the glacier.
  • There is a deep connection to the east through which deepwater flows from Pine Island Bay, a connection that was previously thought to be blocked by an underwater ridge.

Why this is a cause of worry?

  • The warm water is approaching the pinning points of the glacier from all sides, impacting these locations where the ice is connected to the seabed and where the ice sheet finds stability.
  • This has the potential to make things worse for Thwaites, whose ice shelf is already retreating.
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