Tldr; between 2003 and 2011 the Arctic sea ice volume decreased by 50% or 900km³ per year. Latest PIOMAS volume reads 3,400 km³.
With a tremendous effort and more importantly in a public way the Environmental Audit Committee invited and interviewed experts and scientists to collect all evidence about the conditions in the Arctic.
Topics cover everything from methane, permafrost, black carbon over sea ice to polar bears and more. The report went online earlier this day and is the most extensive and actual reader available now.
Here is the paragraph concerning volume and the conclusion:
Since our evidence sessions, some preliminary analysis of data from the CryoSat-2 satellite was broadcast in August 2012, which supported predictions that the Arctic would become ice-free during the summer sooner rather than later. The European Space Agency's CryoSat-2 satellite was launched in 2010 to monitor the changes in the thickness of the Arctic sea-ice and the ice sheets on Greenland and Antarctica.
Professor Seymour Laxon of the Centre for Polar Observation and Modelling—leading the analysis of the Cryosat-2 data—told us that preliminary analysis of the Cryosat-2 data combined with that of NASA's ICESat satellite, showed that between 2003 and 2011 the volume of summer sea ice in October/November had reduced from ~14,000 to ~7,000 cubic kilometres (a 50% decrease).
Averaged over the period, up to 900 cubic kilometres of summer sea-ice was lost a year. He told us that these data "suggest a decrease ... at least as large as that simulated by PIOMAS, and possibly higher".
The Met Office believed that evidence pointed to weather patterns having influenced the rapid loss of sea ice over this summer. The changes in sea-ice volume shown in recent estimates "only extends over a few years" and was not "representative of a long term trend".
Although we recognise the Met Office's and Professor Laxon's concerns about extrapolating trends in volume loss into the future, a simple calculation based on this data points to the Arctic becoming ice-free in the summer within a decade.
There is growing evidence that the damaging effects of climate change are being felt strongly in the Arctic. The ice-cap is retreating. In September 2012 it had reached its lowest extent since satellite records began, and new evidence shows that it is also thinning faster than previously thought.
The general view that the ice-cap is not at risk of a summer collapse in the next few years may need to be revisited and revised. A collapse not only threatens the unique ecosystems there, but would have damaging ramifications for regional and global climate.
I'd like to point at the passage about 'simple calculation' and how the report overrules the scientists resisting to make an extrapolation. It seems in the UK the politics don't want to give the alarm button out of their hands - a refreshing approach to consider scientific results never as alarming. Finally it is up to the reader to make this interpretation, whatever his agenda is.
Read more: publications.parliament.uk