evidence: New research has found that if global temperatures reach 4 degrees Celsius above pre-industrial levels by the end of the century, more than a third of ice shelves surrounding Antarctica could be at risk of collapsing and releasing "unimaginable amounts" of water into the sea. - The research, published in the journal Geophysical Research Letters, suggests that 4C warming could leave 34% of the area of all the Antarctic ice shelves- spreading over about half a million square kilometres- at the risk of collapse. - As part of the study, the researchers also identified Larsen C, the largest remaining ice shelf on the peninsula, as being particularly at risk in a warmer climate. They said other ice shelves facing this threat included Shackleton, Pine Island, and Wilkins.