ABSTRACT
Several teams of climatologists have attempted to estimate the likely effect of the projected changes in greenhouse gas concentrations on the Earth’s climate. The complex climate models they use are mathematical representations of the atmospheric, oceanic and terrestrial processes that are known to occur and that can be formulated in terms of equations capable of being solved by computers. In order to improve our knowledge of possible regional patterns of climate change the Intergovernmental Panel on Climate undertook some regional case studies using results of high resolution general circulation models experiments. As important for agriculture as possible changes in mean climate may be changes in the variability of climate, particularly in the frequency of extreme weather events that today exact a major toll on food output. The problem, however, is that climate varies naturally on a wide range of timescales as a result of many factors such as volcanic eruptions, changes in ocean circulation and solar variations.
