What are climate models? How are they used and what can they say

Climate models are mathematical representations of Earth’s climate system, used to get a picture of what the atmosphere and Earth may look like some time in the future in response to natural and anthropogenic processes. (Reference 14)

There is confidence that climate models provide credible quantitative estimates of future climate change, particularly at continental scales and above. This confidence comes from their ability to reproduce observed features of current climate and past climate changes, their success in making predictions that have been subsequently confirmed by observations, and the foundation of the models based on accepted physical principles. (References 15-16)

Despite the science community’s confidence in climate models, models still show significant errors, mainly resulting from the assumptions that all climate models must make about how the Earth works. The complex and non-linear nature of climate means there will always be a process of refinement and improvement. However, models have evolved to the point where they successfully predict long-term trends and are now developing the ability to predict more chaotic, short-term changes. While it is not possible to precisely project all aspects of future climate (in particular because the magnitude of future impacts is based in large part on the outcomes of social and political decisions that are difficult to anticipate), most climate scientists argue there is enough reliable information on future climate trends and patterns to begin implementing robust adaptation strategies (Reference 17)