Scientists warn of 'planetary emergency'

This year, the ice is "rotten" practically all the way to the North Pole, says Barber, a veteran Arctic researcher and director of the Centre for Earth Observation Science at the University of Manitoba.

"The multi-year ice, what's left of it, is so heavily decayed that it's really no longer a barrier to transportation," he says, explaining how melt ponds have left much of the ice looking like Swiss cheese.

"You could have taken a ship right across the North Pole this year," says Barber, whose research team was involved in a 36-day research cruise in the Beaufort on a Canadian Coast Guard ship.

Flashback: Thing of the past: Chunk of ice 30 miles long, 12 miles wide, and up to 82 feet thick causes Shell to halt Arctic oil drilling