ANTARCTICA’S ‘DOOMSDAY GLACIER’ – THWAITES GLACIER

Context:

Researchers have been able to obtain data from underneath Thwaites Glacier, also known as the ‘Doomsday Glacier’ and have found that the supply of warm water to the glacier is larger than previously thought, triggering concerns of faster melting and accelerating ice flow.

Relevance:

GS-III: Environment and Ecology (Climate Change and related issues)

Dimensions of the Article:

1. About Thwaites Glacier
2. Significance of the Glacier
3. Previous studies on the Glacier
4. What has the new study revealed?

About Thwaites Glacier

• Thwaites Glacier, also called the “Doomsday Glacier”, is in Antarctica and 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.
• The glacier is fast-moving and also melting fast over the years. It contains enough water to raise the world sea level by more than half a metre because of its size.

Significance of the Glacier

• Thwaites’s melting already contributes 4% to global sea level rise each year.
• Studies have found the amount of ice flowing out of it has nearly doubled over the past 30 years.
• 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.

Previous studies on the Glacier

• A 2019 study had discovered a fast-growing cavity in the glacier and also 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.
• 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 likelihood it will melt faster.
• This results in the glacier speeding up, stretching out, and thinning, causing the grounding line to retreat ever further.

What has the new study revealed?

• The researchers have been able to map the ocean currents that flow below Thwaites’s floating part.
• The researchers have been able to identify three inflows of warm water, among whom the damaging effects of one had been underestimated in the past.
• The study also looked at heat transport in one of the three channels which brings warm water towards the glacier from the north.
• This data will help us better calculate ice melting in the future and with the help of new technology, we can improve the models and reduce the great uncertainty that now prevails around global sea level variations.

Why is this a cause of worry?

• The study shows that 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.

-Source: Indian Express