Climate models are suitable tools (computer programs) to simulate climate variables such as temperature, wind, precipitation, humidity, radiation, … based on the laws of physics and physical processes. Sometimes these models refer to general circulation models (GCMs) or Atmospheric-Ocean General Circulation Models (AO-GCMs). They are many types of climate models, and two common categories are global climate models (GCMs) and regional climate models (RCMs). There are also earth system models, which are more advanced and comprehensive versions of GCMs, which also include the carbon cycle and processes in the land surface.

Usually, the global climate models consist of two or three coupled components: the atmhosphere, the oceans, and ice.

There are also simple climate models describing the global mean state, earth system models of intermediate complexity (EMICs) in addition to the more advanced GCMs.