Just another item, which while not conclusive in its self, is an indicator of a feature typical of warming:

Data recorded by the European Space Agency's (Esa) Envisat shows both Canada's Northwest Passage and Russia's Northern Sea Route open simultaneously. - This summer's melt could break the 2007 record for the smallest area of sea ice since the satellite era began in 1979. - Shipping companies are already eyeing the benefits these routes may bring if they remain open regularly. - http://www.bbc.co.uk/news/science-environment-14670433

The two lanes have been used by a number of small craft several times in recent years.

But the Northern Sea Route has been free enough of ice this month for a succession of tankers carrying natural gas condensate from the northern port of Murmansk to sail along the Siberian coast en route for Thailand.

"They're often open at the same time in the sense that with some ingenuity you can get through them," observed Peter Wadhams, an Arctic ice expert from the University of Cambridge.

"But this time they've really been open, with a proper Suez-size tanker going through the Northern Sea Route with a full cargo - that's a real step forward," he told BBC News.

A number of major shipping companies are looking to the opening of these routes to shorten journey times and make their businesses more efficient.

If one pushes its luck and gets caught in the ice, we will have another "ExxonValdez disaster".