An international team of experts brought together by ESA and NASA has produced the most accurate assessment, with the clearest evidence yet of Polar ice losses, from Antarctica and Greenland. Image credit: Ian Joughin, University of Washington
Image above: Over the course of several years, turbulent water overflow from a large melt lake carved this 60-foot-deep (18.3 meter-deep) canyon (note people near left edge for scale).
After two decades of satellite observations, the study finds that the combined rate of ice sheet melting is increasing.
The new research shows that melting of the Antarctic and Greenland ice sheets has added 11.1 mm to global sea levels since 1992. This amounts to about 20% of all sea-level rise over the survey period.
About two thirds of the ice loss was from Greenland, and the remainder was from Antarctica.
Although the ice sheet losses fall within the range reported by the Intergovernmental Panel on Climate Change in 2007, the spread of the estimate at that time was so broad that it was not clear whether Antarctica was growing or shrinking.
The new estimates are a vast improvement – more than twice as accurate – thanks to the inclusion of more satellite data, and confirm that both Antarctica and Greenland are losing ice.
The study also shows that the combined rate of ice sheet melting has increased over time and, altogether, Greenland and Antarctica are now losing more than three times as much ice, equivalent to 0.95 mm of sea-level rise per year, as they were in the 1990s, equivalent to 0.27 mm of sea level rise per year.
The midnight sun casts a golden glow on an iceberg and its reflection in Disko Bay, Greenland. Much of Greenland’s annual ice mass loss occurs through calving of icebergs such as this.
Change in ice sheet thickness per year
NASA | OIB: High and Low over the Rift
This year Operation IceBridge has returned twice to the Pine Island Glacier, the site of a massive glacial crack poised to potentially create an iceberg the size of New York City.
Operation IceBridge returned to the Pine Island Glacier twice in 2012, and NASA glaciologist Kelly Brunt discusses the implications of the glacier’s impending calving event.