Much of Canada's remaining intact ice shelf has broken apart into hulking iceberg islands thanks to a hot summer and global warming, scientists said.

Canada's 4,000-year-old Milne Ice Shelf on the northwestern edge of Ellesmere Island had been the country's last intact ice shelf until the end of July when ice analyst Adrienne White of the Canadian Ice Service noticed that satellite photos showed that about 43% of it had broken off. She said it happened around July 30 or 31.

Two giant icebergs formed along with lots of smaller ones, and they have already started drifting away, White said. The b...