Annual ice mass loss from Greenland in 2019 exceeded the previous record melt in 2012 by 15%, according to a paper published in Communications Earth & Environment. By contrast, melting in the two-year period of 2017 and 2018 was reduced compared to any other two-year period between 2003 and 2019.
The Greenland Ice Sheet is one of the largest contributors to sea level rise, and is associated with about 0.76 mm per year, out of the total of about 3.5 mm per year rise in global mean sea level from 2005 to 2017. The satellite missions GRACE (Gravity Recovery and Climate Experiment) and its follow-on mission GRACE-FO have made it possible to quantify ice mass loss by tracking changes in gravity.
Ingo Sasgen and colleagues analysed data from the two satellite missions from 2003 to 2019 and detected anomalously low melt in 2017 and 2018, followed by record-high melt in 2019 of approximately 532 gigatonnes. Using simulations with a regional climate model, the authors attributed the low melt in 2017–2018 to cold summers in western Greenland and high snowfall in the East.
In an accompanying News and Views article in Nature Climate Change, Yara Mohajerani writes: “It is crucial to understand and closely monitor the changes in mass balance of the Greenland Ice Sheet. Sasgen and colleagues take an important step in that direction.”
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