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:-> continue reading
Since 1979 there is a sea ice extent record for the Arctic with mostly daily measurements. The trend is clear and down, so what is the problem?
Imagine a single idealized ice floe: 1 kilometer long and 1 kilometer wide with a thickness of 2 meter drifting in the Arctic Ocean - a pretty flat cuboid. Roughly 20 centimeter are visible above sea surface as freeboard. NASA’s Arctic Mosaic at highest resolution would represent the floe with 16 white pixels arranged as square.
Let’s further assume bottom- and top melting are equal and and there is enough energy available to melt 1 meter of ice from each of the six sides within a month (30 days). How much ice is left after this period? Exactly, zero.-> continue reading
The question: "When will the Arctic be ice free?" can be posed differently as: "When will we have 100% ice loss during the melting season?". The interactive chart above tries to answer second question. The yearly loss is defined as the difference between maximum and minimum volume.
'Ice free' and 'ice loss' are slightly different concepts or metaphors. A loss of 100% means the Arctic is ice free and a loss of 0% there was no Summer. Ice-free-ness implies the sheet starts phasing out somewhere in the future. Actually this is already happening and it is accelerating. The real question is when will it hit the ground? Having 100% ice loss eliminates all room for discussion, because there is no such thing as 110% loss, 100% loss simply means game over.-> continue reading