We have learnt that changes in climate have occurred and these have been mainly linked to high levels of Greenhouse gas (GHG) emissions. Scientific studies such as the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, 2007 (IPCC FAR) indicate that continued GHG emissions at or above current rates, would cause further warming which could lead to catastrophic changes for the Earth.
To understand how these changes will affect us in the future, climate change scientists use computer-based climate models to generate projections of future climate scenarios for coming centuries. Projections of future climate change are generated using Atmosphere-ocean general circulation models (AOGCMs), which are founded on accepted physical principles and can project aspects of climate, such as temperature and rainfall, for several decades or more into the future.
AOGCMs can give different projections of future climate depending on which Special Report on Emissions Scenarios (SRES) scenario is used.