General circulation models (GCMs) are a class of computer-driven models for weather forecasting; those that
project climate change are commonly called global climate models. GCMs are the core tool for simulating the
coupled climate system using physical representations of the atmosphere, land and ocean surface.6 GCMs simulate
the most important features of the climate (i.e. air temperature and rainfall) reliably at a large scale, although, as
uncertainties are inherent in CGMs, predictions for rainfall intensity, frequency and spatial distribution have a lower confidence.5 CGMs are commonly downscaled to enable their outputs to
be made relevant to regional- or local-scale climate change scenarios