Arctic sea ice extent has shrunk by 2.7 [2.1 to 3.3]%
per decade, with larger decreases in summer of 7.4 [5.0 to 9.8]%
per decade. Mountain glaciers and snow cover on average have
declined in both hemispheres. The maximum areal extent of sea-
sonally frozen ground has decreased by about
7% in the Northern
Hemisphere since 1900, with decreases in spring of up to
15%.
Temperatures at the top
/media/loftslag/IPPC-2007-ar4_syr.pdf