ABSTRACT

Models are used to make projections of atmospheric concentrations of greenhouse gases and aerosols and hence of future climate. Climate models apply simplified representations of the physical laws governing mass and energy exchanges in the ocean-atmosphere system enabling to better understand and redict the consequences of greenhouse gas emissions. It also become integral to policymaking at international levels and, as such, is subject to considerable scrutiny by the global change community. The simplest possible climate model would consider only the incoming and outgoing energy flows to the globe, and compute the resultant globally average annual temperature at the surface. Models provide a framework within which to test hypotheses about a system, and a means of assessing the relative importance of component processes. General circulation models (GCMs) represent the three-dimensional climate system using four primary equations describing the movement of energy and momentum, along with the conservation of mass and water vapour.