An international team of satellite experts has produced the most accurate assessment of ice losses from Antarctica and Greenland to date, ending 20-years of uncertainty.
In a landmark study, published on 30 November in the journal Science, the researchers show that melting of the Antarctic and Greenland ice sheets has contributed 11.1 millimetres to global sea levels since 1992. This amounts to one fifth 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 IPCC in 2007, the spread of the IPCC estimate 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 Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE) is a collaboration between 47 researchers from 26 laboratories, and was supported by the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA).
Led by Professor Andrew Shepherd at the University of Leeds and Dr Erik Ivins at NASA's Jet Propulsion Laboratory, the study combines observations from 10 different satellite missions to develop the first consistent measurement of polar ice sheet changes.
The researchers were able to reconcile the differences between dozens of earlier ice sheet studies through careful use of matching time periods and survey areas, and by combining measurements collected by different types of satellites.
Professor Shepherd, who coordinated the study, said: "The success of this venture is due to the cooperation of the international scientific community, and due to the provision of precise satellite sensors by our space agencies. Without these efforts, we would not be in a position to tell people with confidence how the
Earth's ice sheets have changed, and to end the uncertainty that has existed for many years." The study also found differences in the pace of change at each pole.
Dr Ivins, who also coordinated the project, said: "The rate of ice loss from Greenland has increased almost five-fold since the mid-1990s. In contrast, while the regional changes in Antarctic ice over time are sometimes quite striking, the overall balance has remained fairly constant - at least within the certainty of the satellite measurements we have to hand."
Commenting on the findings, Professor Richard Alley, a climate scientist at Penn State University who was not involved in the study, said: "This project is a spectacular achievement. The data will support essential testing of predictive models, and will lead to a better understanding of how sea-level change may depend on the human decisions that influence global temperatures."
University of Leeds: http://www.leeds.ac.uk
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
With African rhinos and elephants being killed by the thousands, rangers are stepping up their conservation efforts
On the surface of one of Saturn's icy moons, scientists have discovered the possible existence of a very important, life-sustaining element: liquid water.
To catch piracatinga, fishermen cut up river dolphins for lures. Now the government has banned the fishery, turning to genetics to enforce the law
Researchers found that a class of chemicals similar to nicotine and used on corn and soy farms has run off into streams and rivers in the Midwest. There they may be harming aquatic life, like insects.
A report by the Environmental Audit Committee says the UK's coalition government is too soft on neonicotinoid pesticides that harm pollinating insects
The FAA allows hobbyists to use the unmanned aircraft, but professors at private universities and colleges may be out of luck
The baby loggerhead sea turtles emerged on Friday night
The longer the U.S. holds off action to mitigate climate change, the more costly the effort will become, a new report shows
Birds are everywhere, but the greatest concentration of different birds — the "bird mecca" of America — is not in our great parks, not in our forests, not where you'd suppose. Not at all.
An extremely rare, albino hermaphroditic redwood tree was in danger of being sent to the chipper because it was growing too close to the path of a new railroad line in Cotati, Calif. But thanks to local outcry from arborists and the community, the tree is getting a second chance at life.