A few of the main points of the third assessment report issued in 2001 include: An increasing body of observations gives a collective picture of a
warming world and other changes in the climate system; emissions of
greenhouse gases and aerosols due to human activities continue to alter the atmosphere in ways that are expected to
affect the climate; confidence in the ability of models to project
future climate has increased; and there is new and stronger evidence that most of the
warming observed over the last 50 years is attributable to human activities.