Has Arctic Sea Ice Rapidly Thinned?

Reports based on submarine sonar data have suggested Arctic sea ice has thinned nearly by half in recent decades. Such rapid thinning is a concern for detection of global change and for Arctic regional impacts. Including atmospheric time series, ocean currents and river runoff into an ocean-ice-snow model show that the inferred rapid thinning was unlikely. The problem stems from undersampling. Varying winds that readily redistribute Arctic ice create a recurring pattern whereby ice shifts between the central Arctic and peripheral regions, especially in the Canadian sector. Timing and tracks of the submarine surveys missed this dominant mode of variability. Although model-derived overall thinning from the 1960s to the 1990s was less than hitherto supposed, there is also indication of accelerated thinning during the early-mid-1990s.