Pine Island Glacier

An enormous Antarctic glacier has given up an iceberg over 100 square miles in size, the second time in two years it has lost such a large piece in a process that has scientists wondering if its behavior is changing for the worse.

They go to paddle between glistening icebergs or ski on blinding white ice, but a rising number of polar tourists get to see something else, too: the monumental changes wrought by global warming.

Antarctica's Pine Island Glacier, one of the biggest single contributors to world sea-level rise, is melting irreversibly and could add as much as a centimetre (0.4 inches) to ocean levels in 20 years, a study said Sunday.

An enormous Antarctic glacier has given up an iceberg over 100 square miles in size, the second time in two years it has lost such a large piece in a process that has scientists wondering if its behavior is changing for the worse.

They go to paddle between glistening icebergs or ski on blinding white ice, but a rising number of polar tourists get to see something else, too: the monumental changes wrought by global warming.

Antarctica's Pine Island Glacier, one of the biggest single contributors to world sea-level rise, is melting irreversibly and could add as much as a centimetre (0.4 inches) to ocean levels in 20 years, a study said Sunday.