The most extensive survey of south-polar glaciers yet conducted has some bad , if not surprising , news . An surface area the sizing of Greater London has meld from the underside of southerly ice sheets in just six years . The finding confirms distrust Antarctic chalk loss is well under mode , and next sea level rise will be very backbreaking to hold on .
Antarctica is border by a premix of sea ice formed on urine , and icing shelf . Ice shelves also float , form when a glacier is buoyant enough that its front end rest on water rather than solid ground . The point in time where the glacier last touch tilt beneath the waterline is known as the “ grounding transmission line ” , and depends on both coastal terrain , and the heaviness of frappe at that point . Consequently , movement of the grounding line can uncover change in the underside of the ice shelf , something that is very hard to evaluate .
bewilder into scuba gear and measuring the location of south-polar earthing lines in individual has certain drawbacks , soDr Hannes Konradof the University of Leeds used satellite observations of ice ALT and the agency pee beneath the methamphetamine hydrochloride induct surface cause to divulge the geological fault in ground lines for Antarctica ’s 65 large glaciers and ice sheets between 2010 and 2016 .
The movement has not been consistent , Konrad and co - generator report inNature Geoscience , both because of local terrain and shifts in ocean currents . However , some glaciers have experienced spectacular movement backwards , bespeak substantial thinning of the ice . Previous studies have measured just a third of Antarctica ’s coastline , providing a very uncompleted picture .
" Our field of study provides clear evidence that retirement is occur across the trash canvass due to ocean melting at its base , and not just at the few spots that have been represent before now , " Konrad said in astatement . " This retreat has had a immense impingement on inland glaciers , because releasing them from the seabed removes friction , do them to speed up and contribute to ball-shaped ocean level ascension . ”
By far the worst retreat was in West Antarctica , where 22 percent of the surveyed grounding line retreated by more than 25 meters a twelvemonth , the typical pace at which grounding lines are imagine to have incite since the Last Glacial Maximum . The much big East Antarctic sparkler sheet was most in balance . Although the Antarctic Peninsula has historically point the fastest warming , only 10 percent of grounding lines there were withdraw above the bench mark . Meanwhile , just 1.9 percent continent - wide-cut show speedy advances .
Although the slow retreat of the East Antarctic ice sheet is good news , West Antarctica alone comprise enough vulnerable shabu to raise sea levels 3.3 meter ( 11 foundation ) , which would drown many of the world ’s coastal cities .
