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Headline: Crucial ice shelf holding back 'Doomsday Glacier' could collapse within a year

Caption: BY MARK WORGAN A crucial ice shelf attached to Antarctica's vast Thwaites Glacier is expected to break apart within the next year, according to scientists. They fear it will accelerate the retreat of one of the world's most vulnerable glaciers, which is often referred to as the "Doomsday Glacier", due to its potential contribution to rising sea levels. Scientists estimate that if the glacier were to collapse entirely, global sea levels could rise by around 65 centimetres, threatening coastal communities across the world. Researchers studying the glacier say satellite imagery indicates that the eastern ice shelf - a floating extension of the glacier - is close to detaching. Although the glacier itself rests on land, the ice shelf acts as a natural barrier, helping to slow the flow of ice into the Southern Ocean. Writing in the journal Geophysical Research Letters, the authors, Daniel N. Goldberg, Mathieu Morlighem, and Noel Gourmelen state: “Thwaites Glacier in Antarctica is one of the world's most dangerous glaciers for sea level rise. It is losing ice at an alarming rate—more than five times faster than in the 1990s.” Scientists say the loss of this protective shelf could significantly hasten the glacier's decline. The Thwaites Glacier, which is roughly the size of Florida, is the largest glacier in West Antarctica. In places, it is more than 2,000 metres thick and stretches approximately 120 kilometres across, making it the widest glacier on Earth. Scientists have observed rapid melting at Thwaites since the 1980s. Relatively warm ocean water has been flowing beneath the ice shelf, eroding the glacier from below where it sits on bedrock beneath sea level. Since 1992, the glacier has retreated by around 20 kilometres and has lost hundreds of billions of tonnes of ice. Predicting exactly when Thwaites might collapse remains difficult. However, recent modelling suggests the glacier could be losing between 180 billion and 200 billion tonnes of ice annually by 2067. The glacier's gradual retreat forms part of a wider concern about the future stability of the West Antarctic Ice Sheet. Thwaites acts as a critical buttress for neighbouring ice masses, helping to prevent them from sliding into the ocean. According to the British Antarctic Survey, the complete collapse of the West Antarctic Ice Sheet could raise global sea levels by approximately 3.3 metres. Scientists regard such events as potential climate "tipping points" - thresholds beyond which changes become effectively irreversible for thousands of years. Researchers say fractures are developing across the eastern ice shelf, particularly where it is anchored to an underwater ridge and at the glacier's seaward edge. Movement along the shelf's western flank, where the ice is beginning to separate, has reportedly doubled over the past eight months. Like many parts of Antarctica, the shelf is being weakened by warmer, saltier waters rising from deeper regions of the Southern Ocean. While scientists continue to debate the precise mechanisms involved, many believe changes in atmospheric circulation linked to human-induced climate change are playing a key role.

Keywords: feature,photo,thwaites glacier,antarctica,climate change

PersonInImage: The tongue of the Thwaites Glacier.