Global circulation models is computational models which scientists use to estimate or determine how much climate has changed over a period of time(periods are coarse). They use proxy data which they get from geological time periods (e.g. Holocene) to determine what the climate was at that time and what the atmospheric conditions was during that time scale. The sources they use ranges from ices-cores, tree rings, marine sediments, glacial deposits and many more. The evidence that they get is then used to determine possible climate changes in the future. They also use climate forcings like carbon dioxide, aerosols, etc. to give more accuracy to their predictions.
There are many different circulation models that they use which ranges in complexity and computational density. The accuracy of the predictions depends on how far back proxy data are dating. The further back the less accurate predictions will be. Although the climate models of today are farley accurate, they are constantly replaced by models that give more comprehensive monitoring equipment.
Lee- Mervin Mentoor2111335@uwc.ac.za
University of the Western Cape
reviewed by: Ilse Kotzee