Greenland's largest glacier to melt down earlier than expected: Study

New Delhi : The three largest glaciers in Greenland, capable of lifting the earth's water level by approximately 1.3 meters, may melt down earlier than anticipated time, said researchers.

Until 2000, the sea level was rising due to melting of several glaciers. But over the last two decades, the world's ice sheets atop Greenland and Antarctica have become the single largest source of sea level rise.

A team of researchers based in Denmark and Britain used old images and compared them with the new ones clicked in a periodic manner to learn about how much ice has shrunk from Greenland's Jakobshavn Isbrae, Kangerlussuaq Glacier and Helheim Glaciers in the 20th century.

They found that Jakobshavn Isbrae lost more than 1.5 trillion tonnes of ice between 1880-2012, while Kangerlussuaq and Helheim lost 1.4 trillion and 31 billion tonnes from 1900–2012, respectively.

With this, the sea level has already gone up my eight millimeters, wrote researchers.

Shfaqat Abbas Khan, a researcher at the Technical University of Denmark, said using photographs taken before the satellite era was another tool to help recreate the last century's ice loss. “Historical measurements over the 19th and 20th century may hide important information that can significantly improve our future projections,” he told AFP.

But the paper, published in Nature Communications, pointed out that the high-emissions pathway temperature increase was more than four times larger than during the 20th Century, when the three glaciers already added 8 mm to seas. “The worst-case scenario is underestimated. Ice loss may be anywhere from three or four times larger than previous predicted for thee glaciers considered in this study,” said Khan.

A Nature study published in September found that if greenhouse gas emissions continued unabated, ice sheets in Greenland will shed some 36 trillion tonnes this century, enough to lift the global waterline some 10 centimetres.