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.
The results of the UK government's first auction for renewable energy subsidies are a boost for offshore wind, with solar the biggest loser.
Over half of India's population lives in areas with dangerous levels of air pollution. Now that has been translated into years of life lost overall
For the first time, a satellite has calculated the whopping amount of Saharan dust that is blown over the ocean to reach the Amazon rainforest every year
A vast electric fence is being erected around Mount Kenya, one of the world's great refuges for wildlife. Will it help people and animals coexist?
The world's national parks and nature reserves receive eight billion tourist visits a year, generating around $600bn of spending, according to research.
US President Barack Obama vetoes a bill that would have approved construction of the controversial Keystone XL oil pipeline, White House officials say.
Surge in wind power sees share of electricity from renewable sources double between 2010 and 2013, driving down carbon emissions
Camera traps catch sight of the critically endangered Amur leopard. A new census has found that the cat's numbers have doubled since 2007, showing that conservation efforts in Russia to keep the cat from extinction are working.
Nineteen became lodged in a Florida system, sending emergency workers into motion
Coyotes in the Deep South live among a mosaic of agricultural fields and woods but little wilderness. A new study uses tracking collars to understand how these animals thrive in three Southern states.