8
ÒUnequivocalÓ warming of the climate system

lThe oceans and land surface have warmed
lThe troposphere has warmed
lAtmospheric water vapor has increased
lSea level has risen
lGlaciers have retreated over most of the globe
lSnow and sea-ice extent have decreased in the Northern Hemisphere
lIndividually, these changes are consistent with our scientific understanding of how the climate system should be responding to human influences