What Is Normal Arctic Ice Extent?

Guest post by Steven Goddard I have been noticing in recent weeks that NSIDC extent is much closer to their 1979-2000 mean than NANSEN is to their 1979-2007 mean.  This is counter-intuitive, because the NANSEN mean should be relatively lower than NSIDC – as NANSEN’s mean includes the low extent years of the 2001-2007 period.…