Scientists have estimated that the ice sheet melt in Greenland will increase global sea levels by three to 23 centimetres by the next century.

Heatwaves have become a major cause of ice melt in addition to global temperature rises.
Heatwaves have become a major cause of ice melt in addition to global temperature rises. (Gokalp Sakli / AA)

The 3.5 trillion tonnes of Greenland's ice sheet that has melted over the past decade has raised global sea levels by one centimetre and is heightening worldwide flood risks.

The ice sheet atop the world's largest island contains enough frozen water to lift oceans some six metres (twenty feet) globally, new research showed on Monday.

Writing in the journal Nature Communications, researchers said that Greenland's meltwater runoff had risen by twenty-one percent over the past four decades.

Extreme melting events in Greenland have been increasing in frequency for at least forty years.

One-third of the ice lost in the past decade came in just two hot summers, 2012 and 2019, the research showed.

More strikingly, the data provided by the European Space Agency showed that the ice sheet had lost 3.5 trillion tonnes of ice since 2011, producing enough water to raise oceans globally and put coastal communities at higher risk of flood events.

READ MORE: Greenland's ice sheet reaches point of no return

'Heatwaves a major cause of ice loss'

Although it is one of the most studied places on Earth by climatologists, Monday's research is the first to use satellite data to detect Greenland ice sheet runoff.

The images showed significant annual variation in ice melt and, combined with temperature data, showed that heatwaves were increasingly a major cause of ice loss, above and beyond global temperature rises.

Predicting how much Greenland's melt will contribute to rising sea levels is notoriously tricky for scientists who also need to factor in the potential rise caused by other land-based glacier melt.

And, as oceans warm, water expands, also contributing to higher sea levels.

Monday's authors said that the satellite data had allowed them to quickly and accurately estimate how much ice Greenland had lost in a given year, and convert that into sea-level rise equivalent.

"Model estimates suggest that the Greenland ice sheet will contribute between 3-23 cm to global sea-level rise by 2100," said co-author Amber Leeson, senior lecturer in Environmental Data Science at Britain's Lancaster University.

This new spaceborne method of estimation will “refine our estimates of future sea-level rise," she added.

READ MORE: Walloped by heat wave, Greenland sees massive ice melt

Source: AFP