The BBC reports today (http://news.bbc.co.uk/1/hi/sci/tech/8307272.stm) the findings of the Catlin Arctic Survey. The expedition trekked across 435km of ice earlier this year and was assessing the thickness of the ice.
The team found that the ice floes were on average 1.8m thick, typical of "first year" ice which forms during the previous winter and which is more vulnerable to melting than the thicker "multi- year" ice which they had been expecting to traverse. When the ridges of ice between the floes were included, the average ice thickness was 4.8m
Professor Peter Wadhams of Cambridge University, who has been studying the Arctic Ice since the 1960s, is quoted as saying that the Catlin Arctic Survey data supports the view that the Arctic will be ice-free in summer within about 20 years and that much of that decrease would happen within 10 years:
"You'll be able to treat the Arctic as if it were essentially an open sea in the summer," he said.
This echoes a modelling study undertaken by a group headed by Professor Maslowski of NASA in 2007 (reported here: http://news.bbc.co.uk/1/hi/sci/tech/7139797.stm). Using data from 1979-2004, this study predicted that the Arctic would be ice-free in the summer by 2013. A recent Met Office study predicted a temperature increase in the Arctic of as much as 16 degrees C by 2060.
As the Arctic opens up, access to the fossil fuel reserves in the region becomes easier and international tensions are likely to rise, as I've mentioned before on this blog. See here for Canada's territorial claims to the Northwest Passage (http://news.bbc.co.uk/1/hi/sci/tech/7033498.stm ).
However, the most serious environmental risk is the methane locked up under the Arctic which could be released into the atmosphere as the temperature of the region rises. Methane release has been linked to the Permian-Triassic mass extinction which killed 96% of all life (Ryskin et al. Geology, September 2003 pages 741-744).
So we must consider not the immediate bonanza of easier access to fossil fuels (just in time to temporarily avert peak oil) but a further future, in which we face the very real possibility of extinction. Perhaps that will bring the resolve we need.