Intergovernmental Panel on Climate Change, in 2007 assessment report published
Quote:
Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice and rising global average sea level.
…
Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the
observed increase in anthropogenic GHG concentrations. It is likely that there has been significant anthropogenic warming over the past 50 years averaged over each continent (except Antarctica).