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.
New evidence shows that catastrophic climate change probably destroyed 96% of species at the end of the Permian period. It could happen again
Up to 120,000 animals are feared dead in central Kazakhstan, and still the cause is not known. Vets are investigating three main possibilities
New study predicts glaciers in the Everest region could decline by 70 to 99 percent over the next eight decades
The Obama administration announces a regulation it says is aimed at protecting the country's rivers, lakes and other waterways from pollution. But critics say it's a massive regulatory overreach.
The Antarctic ozone hole would have been 40% bigger and a hole over the Arctic would have opened up if ozone-depleting chemicals had not been phased out, according to research.
Storms and other extreme weather in Mexico, Texas, Oklahoma and Alaska could be the first signs that climate's bad boy is back with a vengeance
China has rapidly cleaned up its coal plants. Now comes the hard part.When William Latta first came to China, in 2005, he intended to look for companies to acquire for the French power giant Alstom. He wound up creating his own.
Scientists artificially inseminated a 100-year-old Yangtze giant softshell turtle, the last known female of her species
Researchers have identified a third gene that causes congenital insensitivity to pain when mutated
Ragweed pollen is the bane of many lives in the US, and climate change could help the plant become much more common in Europe by 2050