CALGARY, Alberta — A chunk of ice bigger than the area of Manhattan broke from an ice shelf in Canada’s far north and could wreak havoc if it starts to float westward toward oil-drilling regions and shipping lanes next summer, a researcher said on Friday. Global warming could be one cause of the break of the Ayles Ice Shelf at Ellesmere Island, which occurred in the summer of 2005 but was only detected recently by satellite photos, said Luke Copland, assistant professor at the University of Ottawa’s geography department. It was the largest such break in nearly three decades, casting an ice floe with an area of 66 square km (25 square miles) adrift in the Arctic Ocean, said Copland, who specializes in the study of glaciers and ice masses. Manhattan has an area of 61 square km (24 square miles). The mass is now 50 square km (19 square miles) in size. ‘The Arctic is all frozen up for the winter and it’s stuck in the sea ice about 50 km (30 miles) off the coast,’ he said. ‘The risk is that next summer, as that sea ice melts, this large ice island […]