PENNSYLVANIA: A massive block of ice the size of Delaware broke off from Antarctica and is now freely floating in the Weddell Sea. Weighing around 1 trillion tons, the iceberg is the largest on record and poses no immediate threat to sea levels. However, scientists said the break is just a preview of the effects of global warming on marine ice shelves. They said the the break may have altered the profile of the continent’s western peninsula for decades to come.
Researchers at Project Midas, a team from Swansea University and Aberystwyth University in Britain, confirmed the break using data from NASA satellites. They had been monitoring a rift in an ice shell called Larsen C for years before it began to grow rapidly in January, increasing in length to approximately 120 miles. Lead investigator Adrian Luckman of Swansea University said, “We have been anticipating this event for months, and have been surprised how long it took for the rift to break through the final few kilometres of ice. It may remain in one piece but is more likely to break into fragments. Some of the ice may remain in the area for decades, while parts of the iceberg may drift north into warmer waters.”
The main argument now is whether the break away was induced due to man-made climate change. Glaciologist at Project Midas, Martin O' Leary said icebergs break away naturally in a process known as calving. “We're not aware of any link of human-induced climate change” in this case he said. The team said that even if that is the case, the event works as a proxy to help them study how ice shelves fracture.
The calving in question has reduced Larsen C by over 12 per cent. Many worry on its potential effect on the remainder of the shelf, among Antarctica's largest. Named for the man who discovered it in 1893, the Norwegian explorer Carl Anton Larsen, the Larsen Ice Shelf is actually a series of many floating chunks of ice. Larsen C, the largest, was first photographed in the 1960s. Even then, the fateful crack was already visible, according to NASA. Ice shelves form as ice sheets - large accumulations of snow on top of a land mass - flow downhill to the ocean. The shelves naturally shed weight in the form of icebergs - the process called calving - or through melting on the bottom.
“That’s just the way Antarctica works,” said Helen Fricker, a glaciologist at the Scripps Institution of Oceanography at UC San Diego who studies ice shelves. One way to know if a sheet is healthy is to see if it’s gaining as much ice as it is losing. Ice sheets grow as snow accumulates and freezes on the surface, and lose ice through melting and calving of their shelves. If a large enough iceberg calves off, an ice shelf could collapse. That’s what happened to Larsen C’s neighbours, Larsen A and Larsen B, in 1995 and 2002 respectively.
