The following graphs are cause for concern. They show that
(1) the area of arctic ice at its minimum yearly extent (usually in September) was this year only a half of the average value of the 1980s.
(2) the volume of arctic ice at its minimum yearly extent is on the decline with this year’s level just a fifth of that in 1979!
(3) Since the volume is decreasing at a faster rate than the area, this indicates that the mean ice thickness is also decreasing.
More on this at the following links.
Poles apart: A record-breaking summer and winter – Arctic Sea Ice News & Analysis, NSIDC
Ice records fall at both poles – New Scientist
Arctic sea ice graphs (Nevin Acropolis)
PIOMAS September 2012 (minimum) – Arctic Sea Ice in Arctic Sea Ice Blog (Nevin Acropolis)