Coupled climate models
A climate model is a computer representation of the real world, based on the fundamental laws of physics. We use these models to:
- forecast or project future weather and climate
- understand the processes that cause changes in our climate.
Scientists usually use separate software to simulate each part of the Earth system. For example, the oceans, atmosphere and ice regions. A coupled model brings these together to form a complete model of the Earth system.
Our ACCESS-S model, used for seasonal forecasting and attribution, is an example of a coupled model.
Sharing coupled model results
Scientists around the world take part in coordinated efforts, such as the World Climate Research Programme's Coupled Model Intercomparison Project (CMIP), to:
- run standardised experiments
- evaluate and compare climate model simulations.
This project started in 1995 and its most recent generation is CMIP6. Work is in progress to update the projections further with CMIP7.
Australia contributes simulations from 2 models to CMIP6 – ACCESS-ESM1.5 and ACCESS-CM2. This happens through a consortium led by CSIRO, including:
- Australia’s climate simulator (ACCESS-NRI)
- the National Computational Infrastructure (NCI)
- the Bureau of Meteorology
- several Australian universities.
Using CMIP data
The CMIP archive contains climate model output from modelling centres around the world. To enable comparison, all models run a common set of experiments. These include:
- simulations of the historical climate
- future scenarios, from low to high greenhouse gas emissions.
Most researchers across Australia use CMIP output stored at the NCI. It has CMIP5 and CMIP6 products, including on 1.5 degree grids to support comparison studies.
The Australian Climate Service uses CMIP data to produce its down-scaled climate change projections – that is, high-resolution projections that provide more locally relevant information.