Image copyright BAS Image caption Parts of West Antarctica are undergoing significant change 
 
 Melting ice is fuelling sea-level rise around the coast of Antarctica, a new report in Nature Geoscience finds. 
 
 Near-shore waters went up by about 2mm per year more than the general trend for the Southern Ocean as a whole in the period between 1992 and 2011. 
 
 Scientists say the melting of glaciers and the thinning of ice shelves are dumping 350 billion tonnes of additional water into the sea annually. 
 
 This influx is warming and freshening the ocean, pushing up its surface. 
 
 "Freshwater is less dense than salt water and so in regions where an excess of freshwater has accumulated we expect a localised rise in sea level," explained Dr Craig Rye from the University of Southampton, UK, and lead author on the new journal paper. 
 
 Globally, sea levels are going up, in part because of the contribution of the world's diminishing ice fields. This is well known. 
 
 But the Nature Geoscience report is the first to show the direct consequences to sea surface height (SSH) around Antarctica itself. 
 
 While the satellite data record indicates there has been a general upward trend in SSH in the Southern Ocean south of 50 degrees of up to 2.4mm per year, those satellites also indicate a more rapid rise in waters sitting on the continental shelf. 
 
 Mass losses 
 
 Modelling by Dr Rye's team suggests that this additional 2mm per year can be attributed almost exclusively to freshwater runoff from Antarctica, and not to some climatic oscillation that might make sea levels "breathe" up and down on decadal timescales. 
 
 "We can estimate the amount of water that wind is pushing on to the continental shelf, and show with some certainty that it is very unlikely that this wind forcing is causing the sea level rise," Dr Rye told BBC News. 
 
 "And because we can model the freshwater forcing, and the fact that this is so much more like what we see in the real world, we can come to the confident conclusion that the signal is driven by freshwater forcing." 
 
 Recent satellite studies have underlined the increased mass losses occurring in Antarctica. 
 
 Much of this accelerated ice discharge is occurring in the continent's western sectors, particularly in the Amundsen Sea Embayment and along the Antarctic Peninsula. 
 
 In contrast to land ice, the sea ice around Antarctica stands at record levels and is becoming more extensive. 
 
 The growth is small and very regional in character, but nonetheless significant. 
 
 Quite how the freshening of surface waters might be influencing this phenomenon is now a target for study. 
 
 "That's a really interesting question which I'd like to look into with further research," Dr Rye said. 
 
 Jonathan.Amos-INTERNET@bbc.co.uk and follow me on Twitter: @BBCAmos ||||| German researchers have established the height of the Greenland and Antarctic ice caps with greater precision than ever before. The new maps they have produced show that the ice is melting at an unprecedented rate. 
 
 The maps, produced with a satellite-mounted instrument, have elevation accuracies to within a few metres. Since Greenland’s ice cap is more than 2,000 metres thick on average, and the Antarctic bedrock supports 61% of the planet’s fresh water, this means that scientists can make more accurate assessments of annual melting. 
 
 Dr Veit Helm and other glaciologists at the Alfred Wegener Institute’s Helmholtz Centre for Polar and Marine Research in Bremerhaven, Germany, report in the journal The Cryosphere that, between them, the two ice sheets are now losing ice at the unprecedented rate of 500 cubic kilometres a year. 
 
 The measurements used to make the maps were taken by an instrument aboard the European Space Agency’s orbiting satellite CryoSat-2. The satellite gets closer to the poles − to 88° latitude − than any previous mission and traverses almost 16m sq km of ice, adding an area of ice the size of Spain to the big picture of change and loss in the frozen world. 
 
 CryoSat-2’s radar altimeter transmitted 7.5m measurements of Greenland and 61m of Antarctica during 2012, enabling glaciologists to work with a set of consistent measurements from a single instrument. 
 
 Over a three-year period, the researchers collected 200m measurements in Antarctica and more than 14m in Greenland. They were able to study how the ice sheets changed by comparing the data with measurements made by Nasa’s IceSat mission. 
 
 Greenland’s volume of ice is being reduced at the rate of 375 cubic km a year. In Antarctica, the picture is more complex as the West Antarctic ice sheet is losing ice rapidly, but is growing in volume in East Antarctica. 
 
 Overall, the southern continent − 98% of which is covered with ice and snow − is losing 125 cubic km a year. These are the highest rates observed since researchers started making satellite observations 20 years ago. 
 
 “Since 2009, the volume loss in Greenland has increased by a factor of about two, and the West Antarctic ice sheet by a factor of three,” said Angelika Humbert, one of the report’s authors. 
 

– Around 61% of the world's freshwater is locked up in Antarctic ice—but a new study warns that accelerating melting on the continent is helping push up the sea levels around it. Researchers found that between 1992 and 2011, sea levels rose more around Antarctica than in the Southern Ocean as a whole. "Freshwater is less dense than salt water, and so in regions where an excess of freshwater has accumulated we expect a localized rise in sea level," the author of a study published in Nature explains to the BBC. The researchers say their models suggest freshwater runoff, not natural fluctuations, is the only explanation for the 2mm-per-year rise. "We can estimate the amount of water that wind is pushing onto the continental shelf, and show with some certainty that it is very unlikely that this wind forcing is causing the sea level rise," the lead researcher says. The researchers say the freshening of the water may explain growth in sea ice in the area, though that growth comes as new satellite-produced maps show that ice sheets on land are melting at an unprecedented rate, the Guardian notes. (Last month, researchers revealed that they had found life half a mile below the West Antarctic Ice Sheet.)