Greenland and Antarctica have lost around 11 trillion tonnes of ice since the 1970s, contributing more than three centimetres to global sea-level rise. A new assessment by the Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE), an international collaboration supported by ESA and NASA, reveals that the story is not simply one of surface melting: 84% of the loss was discharged into the ocean by glaciers accelerating towards the coast, underlining the growing influence of a warming ocean on polar ice. Bringing together 42 independent surveys from 27 satellite missions, the study – published in the Nature journal Scientific Data – provides the longest satellite record of ice-sheet change assembled to date.
The latest IMBIE assessment draws on ice sheet mass balance datasets generated through ESA’s Climate Change Initiative using observations from multiple satellite missions.
“State-of-the-art processing methods developed as part of Greenland and Antarctica CCI research projects have been used in this study to track the ice sheets' contribution to sea level rise from 1992 to present day, offering a long-term view of the evolution of the ice sheets during the satellite era,” explains lead author of the study, Dr Inès Otosaka of Northumbira University.
Anna Maria Trofaier, ESA Cryosphere scientist, puts the study into context: "In climate science, reducing uncertainty is as important as measuring change itself. The development of robust, error-characterised climate data records is therefore essential. By combining observations across missions, institutions and decades, IMBIE provides a long-term perspective on ice-sheet evolution, strengthening confidence in the trends we observe while improving our understanding of the uncertainties that accompany them."
Read the full article here: ESA - Faster-flowing glaciers fuel decades of polar ice loss