An iceberg the size of Luxembourg which has broken away from Antarctica was caused by a collision with another iceberg rather than being a result of global warming. "An iceberg the size of Luxembourg has broken away from the Antarctic continent and is drifting towards an area of the Southern Ocean that plays a critical role in driving the world's ocean circulation – the global 'conveyor belt' of circulating sea water. The floating iceberg, which contains enough fresh water to supply a third of the world's population for a year, is 48 miles long, 22 miles wide, has a surface area of 965 square miles and an average thickness of 1,300 feet. It is one of the largest icebergs to be monitored by scientists. Researchers believe the iceberg may be big enough to interfere with the flow of extremely cold and salty water that naturally sinks to the seabed in this part of the southern hemisphere to form the deep current of water that is transported around the world along the sea floor. This ocean circulation transports heat and nutrients and is vital for the marine food chain as well as maintaining important currents, such as the Gulf Stream. The giant iceberg broke away from the Mertz Glacier tongue in East Antarctica about three weeks ago. The 'calving' occurred when another, equally large, iceberg rammed against the Mertz Glacier tongue. 'The calving itself hasn't been directly linked to climate change but it is related to the natural processes occurring on the ice sheet,' Rob Massom, a scientist at the Australian Antarctic Climate and Ecosystems Co-operative Research Centre in Hobart, Tasmania, told the news agency Reuters."