A weather system can be described by how quantities such as the speed, pressure and temperature of the gases behave in the atmosphere, and the water behaves in the ocean. These quantities move in 3-dimensional space.

A large number of complex mathematical equations describe their behaviour. However, they are too complex to solve by hand, or on a personal computer.

Climate models need a lot of computing power.

Supercomputers provide an extremely powerful, fast environment with many thousands of processing units to process these complex equations.

More and more climate processes have been incorporated into global models over many decades as computing power has increased.

Illustration of the processes added to global climate models over the decades, from the mid-1970s, through the first four IPCC assessment reports. Source: Adapted from the IPCC