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).
Image credit: Ian Joughin
To request an interview with Prof Andrew Shepherd, School of Earth & Environment, University of Leeds, please contact Esther Harward, University of Leeds Communications Office, phone +44 (0)113 343 4196 or email firstname.lastname@example.org
A reconciled estimate of ice sheet mass balance by Prof Shepherd et al is published in Science on 30 November 2012, DOI: 10.1126/science.1228102. For a copy of the paper please visit the website http://www.eurekalert.org/jrnls/sci/ (access granted to journalists registered with Science) or contact the Science press team, phone +1 202-326-6440 or email email@example.com