Predicting Climate Change using Response Theory: Global Averages and Spatial Patterns

Understand

The provision of accurate methods for predicting the climate response to anthropogenic and natural forcings is a key contemporary scientific challenge.

• Using a simplified and efficient open-source general circulation model of the atmosphere featuring O($10^5$) degrees of freedom, we show how it is possible to approach such a problem using nonequilibrium statistical mechanics.
• Response theory allows one to practically compute the time-dependent measure supported on the pullback attractor of the climate system, whose dynamics is non-autonomous as a result of time-dependent forcings.
• We propose a simple yet efficient method for predicting - at any lead time and in an ensemble sense - the change in climate properties resulting from increase in the concentration of CO$_2$ using test perturbation model runs.