Greenland’s largest glaciers may lose more ice than predicted

The three largest glaciers in Greenland contributed around 8.1 mm to the rise in sea levels between 1880–2012 reports a paper in Nature Communications. The study suggests that under the current worst case scenario for global temperature rise by the end of the century (RCP 8.5), these glaciers could lose more ice than has previously been predicted.

Jakobshavn Isbræ, Kangerlussuaq Glacier and Helheim Glacier in Greenland, hold enough ice to raise sea levels by around 1.3 metres. Previous studies have estimated the ice loss from these glaciers since the 1970s, but changes which took place throughout the 19th and 20th centuries are poorly understood.

Shfaqat Abbas Khan and colleagues used historical photographs to calculate the amount of ice lost from these glaciers from 1880–2012. The authors estimate that Jakobshavn Isbræ lost a total mass of approximately 1,518 gigatonnes over this period, while Kangerlussuaq Glacier and Helheim Glacier lost 1,381 and 31 gigatonnes from 1900–2012, respectively. They calculate that this translates to an 8.1 mm rise in sea levels.

Under RCP 8.5, models suggest that the mass loss from these three glaciers could contribute 9.1–14.9 mm to sea level rise by 2100. However, with global temperatures predicted to rise by an additional 3.7 °C by 2100 under RCP 8.5, approximately four times larger than that which has taken place since 1880, the authors suggest that the ice loss from the three glaciers could exceed current projections for this scenario.

doi: 10.1038/s41467-020-19580-5

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