Melting from Greenland’s ice sheet broke records last year — losing a total of 532 gigatonnes of mass overall, analysis of satellite data has revealed.
Experts led from Germany found that the ice loss in 2019 was 15 per cent higher than the previous worst year on record — which was 2012.
However, they also noted that favourable conditions in 2017–2018 meant that melting was lower than in any other two-year period between 2003–2019.
Researchers can assess how fast ice mass is lost by tracking changes in gravity as recorded by the Gravity Recovery and Climate Experiment (Grace) missions.
Melt from the Greenland Ice Sheet is one of the largest contributors to sea level rise and presently contributes an increase of around 0.03 inches (0.76 mm) annually.
In total, sea levels rose by around 0.14 inches (3.5 mm) each year from 2005 to 2017, researchers have calculated.
The findings come a week after a study revealed that Greenland’s glaciers have already passed what researchers have called the ‘point of no return’.
This, experts warned, means that the ice would now continue to melt away even if global warming could be completely stopped.
Melting from Greenland’s ice sheet broke records last year — losing a total of 532 gigatonnes of mass overall, analysis of satellite data has revealed. Pictured, icebergs float away to sea near Kulusuk, Greenland, in this file photo from August 16, 2019
Experts led from Germany found that the ice loss in 2019 was 15 per cent higher than the previous worst year on record — 2012. Pictured, the extent of Greenland’s ice loss over time as recorded by the Grace missions. The annual fluctuations represent summer and winter
In their study, glaciologist Ingo Sasgen from the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research and colleagues analysed data taken from the two satellite missions operating from 2003–2019.
The researchers found that Greenland experienced unusually low levels of melt in both 2017 and 2018, followed by record-breaking levels of around 532 gigatonnes in the following year.
In comparison, the melt back in 2012 was just 464 gigatonnes, the team noted.
Based on simulations using a regional climate model, the authors suggest that the low melt levels in 2017–2018 may have been due to their having been cold summers in western Greenland coupled with high levels of snowfall in the east.
According to the team, there is ‘an abrupt transition from a reduced rate of mass loss in 2017-2018 (58 per cent lower than 2003–2018 average) to a strongly enhanced rate of mass loss in 2019 (July mass loss rate 5 per cent above 2003-2016 average)’.
‘A similar but inverse transition occurred between the record melt year of 2012 and the near-balance year of 2013,’ they continued.
In addition, the researchers found that the overall ice loss last year exceeded the previous record loss measured by the satellite back in 2012.
This means that ‘2019 exhibited the largest mass loss on record’, following a trajectory of increasing ice loss since the late 1990s.
Based on simulations using a regional climate model, the authors suggest that the low melt levels in 2017–2018 may have been due to their having been cold summers in western Greenland coupled with high levels of snowfall in the east. Pictured, the average high-latitude temperatures around Greenland in both 2017–2018 (left) and 2019 (right)
‘It is crucial to understand and closely monitor the changes in mass balance of the Greenland Ice Sheet,’ said earth scientist Yara Mohajeran of the University of California, Irvine, who was not involved in the present study. Pictured, crevasses form on Greenland’s Helheim glacier
‘It is crucial to understand and closely monitor the changes in mass balance of the Greenland Ice Sheet,’ said earth scientist Yara Mohajeran of the University of California, Irvine — who was not involved in the present study.
‘Sasgen and colleagues take an important step in that direction.’
‘To put this 2019 Greenland melt rate into context, 532 gigatonnes in one year is equivalent to around six Olympic-sized swimming pools every single second of the year,’ added climate scientist Ed Hawkins of the University of Reading.
‘It is devastating that 2019 was another record year of ice loss,’ commented environmental scientist Twila Moon of the University of Colorado at Boulder. Pictured, an antenna at the New York University base camp overlooking Greenland’s Helheim glacier as seen in August 2019
‘It is devastating that 2019 was another record year of ice loss,’ commented environmental scientist Twila Moon of the University of Colorado at Boulder.
‘In 2012, it had been about 150 years since the ice sheet had experienced [a] similar melt extent, and then a further 600-plus years back to find another similar event.’
‘We have now had record breaking ice loss twice in less than 10 years — and the ice sheet has lost ice every year for the past 20.’
‘The research further confirms that we are in a dire state of ice loss in Greenland. This ice loss translates directly to rising seas around the world.’
The full findings of the study were published in the journal Communications Earth & Environment.