Climate scientists discover new weak point of the Antarctic ice sheet
9 May 2012
PR No. 02/2012
Reporting this week (Thursday 10 May) in the journal Nature, scientists from ice2sea highlight how future climate change will drive considerably greater quantities of warm water toward Antarctica, and increase the loss of ice from the continent.
Researchers from the Alfred Wegener Institute (AWI) in Germany and UK Met Office Hadley Centre completed a series of experiments for ice2sea – a major EU FP7 programme that aims to improve projections of future sea-level rise. In these, models of the global ocean were driven with projections of climate produced for two possible carbon emission scenarios. A common feature in all the simulations is a massive increase in melt in an unexpected part of Antarctica, the Filchner-Ronne Ice Shelf. During the second half of the 20th Century, the melting from the underside of this ice shelf increases dramatically as water that is two degrees Celsius warmer than today is driven towards the ice sheet for the first time.
Lead Author, Dr. Hartmut Hellmer, from the Alfred Wegener Institute, said:
“The Filchner-Ronne Ice Shelf was not really on our radar screen because the satellite data show that current change is occurring on the opposite side of West Antarctica. But our models have highlighted a mechanism which drives warm water towards the coast with an enormous impact on the Filchner-Ronne Ice Shelf in the coming decades.”
The study shows the degree to which atmospheric and ocean change will be connected in future decades. These models show that the reduced concentration of sea ice in future alters the effect of wind on surface waters and re-directs the coastal current over the 700-m deep sill towards Filchner Ice Shelf.
Professor David Vaughan, leader of ice2sea, said:
“Across Europe, participants in the ice2sea programme are working hard to ensure that the next report from the Intergovernmental Panel on Climate Change is underpinned by a much better understanding of the future of the ice sheets and their impact on global sea level rise. This study takes us much closer to that goal in showing the high vulnerability of parts of Antarctica to changes in ocean circulation.”
This is the second piece of ice2sea research to be published in Nature in recent weeks. In April 2012 ice2sea scientists published research that showed the majority of ice currently being lost from the Antarctic ice sheet is due to recent changes in ocean circulation as warmer water comes into contact with several floating ice shelves.
ENDS
Notes:
Twenty-first-century warming of a large Antarctic ice-shelf cavity by a redirected coastal current: Hartmut H. Hellmer, Frank Kauker, Ralph Timmerman, Jurgen Determan &, Jamie Rae is published this week in the journal Nature.
Given the improved understanding of the role of ice shelves in controlling the continental ice sheet, it is expected that increased melting beneath the Filchner-Ronne Ice Shelf will cause melting of ice and a contribution to sea-level rise. Quantifying that contribution is a focus of current research within ice2sea, which will be reported later in 2012.
The forecasts of the current study are based on independent calculations of the ocean models BRIOS (Bremerhaven Regional Ice Ocean Simulations) and FESOM (Finite Element Sea Ice Ocean Model). The models were run from 1860 and correctly reproduced conditions to the present. The scientists then used the atmospheric projections of the models developed by the British Met Office Hadley Centre in Exeter to drive the ocean models to 2200.
Printable images, graphics and an animation of the predicted changes in the Weddel Sea are available at: http://www.awi.de/de/aktuelles_und_presse/pressemitteilungen/
Scientist contact details:
Dr Hartmut Hellmer, Lead Author, Alfred Wegener Institute (AWI)
Tel: 0471 4831-1794; email: Hartmut.Hellmer@awi.de
Professor David Vaughan, Leader of the ice2sea programme
Tel: +44 (0) 1223 221643; email: david.vaughan@bas.ac.uk
Communications:
Sina Löschke, Communications and Media Department, Alfred Wegener Institute (AWI)
Tel: 0471 4831-2008; email: Sina.Loeschke@awi.de
Heather Martin, Communications for ice2sea, British Antarctic Survey (BAS)
Tel: +44 (0)1223 221226, email: heather.martin@bas.ac.uk
The Alfred Wegener Institute (AWI) conducts research in the Arctic and Antarctic, and in the high and mid-latitude oceans. The Institute coordinates German polar research, providing important infrastructure such as the research ice breaker Polarstern, and research stations in the Arctic and Antarctic to the national and international scientific world. The Alfred Wegener Institute is one of the 18 research centres of the Helmholtz Association, the largest scientific organisation in Germany.
Ice2sea brings together the EU’s scientific and operational expertise from 24 leading institutions across Europe and beyond. Improved projections of the contribution of ice to sea-level rise produced by this major European-funded programme will inform the fifth IPCC report (due in 2013). In 2007, the fourth Intergovernmental Panel on Climate Change (IPCC) report highlighted ice-sheets as the most significant remaining uncertainty in projections of sea-level rise. Understanding about the crucial ice-sheet effects was “too limited to assess their likelihood or provide a best estimate of an upper bound for sea-level rise”.
Ice2sea is funded by the European Union’s Seventh Framework Programme (FP7): www.ice2sea.eu
