A physical model for the global mean surface air temperature anomalies over the past century

Abstract

OKSERVATIONS show that the global mean surface air temperature has risen by about 0.62"C over the past century[ll. This rise is widely thought to be the result of increasing atmospheric concentrations of greenhouse gases such as carbon dioxide, methane, nitrous oxide and chlorofluorocarbons[2', but there are at least two sources of natural climate variability, volcanic aerosols and solar variability, adding to the anthropogenic changes, which may confuse our interpretation of the observed temperature records. In this study, we used a physically based model developed recently and available data to examine what an important roles the solar variability, the greenhouse gases (GHGs) and the volcanic aerosols play in the present climatic variation.