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Context

• According to a new study, no matter how much carbon emissions are reduced, rapid melting of West Antarctica's ice sheet owing to warm waters surrounding it is now unavoidable.

Details

• The study, titled 'Unavoidable future increase in West Antarctic ice-shelf melting over the twenty-first century,' was published last week in Nature.
• If the ice sheet melted completely, it would raise global mean sea level by 5.3 meters (17.4 feet).
• If this occurs, it could have disastrous consequences for millions of people living in vulnerable coastal cities around the world, including India.

What is an Ice Sheet?

• An ice sheet is a mass of glacial ice that covers more than 50,000 square kilometers of land — roughly the size of Uttarakhand.
• Today, the planet has two large ice sheets: the Greenland ice sheet and the Antarctic ice sheet.
• They contain almost two-thirds of all freshwater on the planet.
• This means that as ice sheets gain mass, they contribute to a decrease in global mean sea level while losing mass contributes to a rise in global mean sea level.

What is the melting rate of the West Antarctic ice sheet?

• Ice sheets melt through a variety of methods. One of these is when warm ocean waters melt ice shelves, which are the borders of floating ice sheets.
• Ice shelves help to stabilize the land-based glaciers behind them.
• When an ice shelf thins or disappears, glaciers accelerate, dumping more ice into the ocean and raising sea levels.
• Sea ice, the free-floating ice that surrounds the polar regions, is distinct from both ice shelves and ice sheets.
• Sea ice forms when seawater freezes.
• The same thing is happening in West Antarctica.
• For decades, the region's ice shelves have been dwindling, glaciers have been melting faster, and the ice sheet has shrunk.

Findings of the Study

• The study predicts severe and extensive future warming of the West Antarctica Sea, as well as greater melting of ice shelves.
• This will very certainly result in greater sea-level rise, affecting coastal towns around the world, including India.
• India is vulnerable to sea level rise due to its vast coastline and dense population.
• If coastal communities cannot afford to defend themselves against increasing sea levels, such as by erecting walls, residents will have to relocate or become refugees.

Is there any hope left?

• Although the findings are dismal, the report emphasizes that they should not deter attempts to minimize the effects of climate change.
• The melting West Antarctic ice sheet, according to the experts, is just one component of sea level rise, which is just one effect of climate change.

Way Forward

• There are many other impacts that we can still avoid or limit: like the loss of the East Antarctic Ice Sheet, or the severity of heatwaves, droughts, and extreme rainfall.

PRACTICE QUESTION Discuss the potential consequences of ice sheet melting on global sea levels and climate patterns.