The research attributed 25% of rises in sea level to melting ice sheets. This represents a fivefold increase in that element’s contribution said the scientists, who drew their evidence collected as part of IMBIE, the Ice Sheet Mass Balance Intercomparison Exercise.
Backed by funds from NASA and the European Space Agency, IMBIE has studied some 50 satellite surveys of Antarctica and Greenland during a period of nearly three decades, between 1992-2020.
The ice depletion is measured by satellites tracking changes in ice sheets’ volume, gravitational pull and ice flow.
In 2019 a new record was created when the ice sheets lost an unprecedented 612 billion tonnes, attributed in part to an Arctic summer heatwave. This saw Greenland alone losing 444 billion tonnes, while Antarctica lost 168 billion tonnes.
Of the rise in global sea levels since 1992, a 21 millimetre rise is attributed to ice sheet melting, split nearly almost two thirds (13.5 mm) on Greenland’s part and one third (7.4 mm) from Antarctica.
Back then ice sheet melting accounted represented just 5.6 % of sea level rise. Today it accounts for 25.6 % of the total. If the ice sheets continue to lose mass at this pace, the IPCC predicts that they will contribute between 148 and 272 mm to global mean-sea level by the end of the century.
This third assessment from the IMBIE Team involved 68 polar scientists from 41 international organisations using measurements from 17 satellite missions, including for the first time from the GRACE-FO gravity mission.
Dr Diego Fernandez, Head of Research and Development at ESA, said: “This is another milestone in the IMBIE initiative and represent an example of how scientists can coordinate efforts to assess the evolution of ice sheets from space offering unique and timely information on the magnitude and onset of changes.
“The new annual assessments represent a step forward in the way IMBIE will help to monitor these critical regions, where variations have reached a scale where abrupt changes can no longer be excluded.”
The new dataset is available on the British Antarctic Survey website.