It's old, cold and enormous and now it's floating free in the Arctic Ocean.
Scientists say a 4,500-year-old ice shelf broke off last month surprising scientists and adding fuel to the climate change debate.
The Markham Ice Shelf is 19 square miles in size, about the size of Manhatten, and has now broken cleanly away from Ellesmere Island in Canada's northern Arctic.
Arctic ice shelf specialist Derek Mueller says, "The Markham...
