He (one of Canada's top sea-ice experts) pointed out the Arctic continued to lose multiyear ice even in 2008 and 2009, when total ice coverage rebounded somewhat.

True multiyear ice – the thick, hard stuff that stops ships – now comprises about 18 per cent of the Arctic ice pack. In 1981, when Prof. Barber first went north, that figure was 90 per cent.

“This is all just part of a trajectory moving toward a seasonally ice-free Arctic,” he said. “That's happening more quickly than we thought it would happen.”