Climate Modelling Part 2


Earth System Models (ESMs) are climate models which in addition to physical processes also simulate a range of relevant biogeochemical cycles, e.g. the carbon cycle, dynamical vegetation, atmospheric aerosols and chemistry. Relative to conventional purely physical coupled atmosphere - ocean General Circulation Models (GCMs), ESMs include many more process representations, variables, and also climate relevant feedbacks on both short - instantaneous to few years - as well as long - decades to centuries and millennia - time scales. ESMs are continuously expanding to include further processes. For example, the ESMs participating in the 6th Phase of the Coupled Model Intercomparison Project (CMIP6) will for the first time include interactive ice sheets and several models will have interactive chemistry and aerosols. ESMs are common tools to understand and project climate change and can also contribute to the design of feasible mitigation pathways for example through the computation of allowable emissions for a specific temperature target. The lecture gives an overview of the main components of ESMs and explains the underlying basics and the numerical formulation of the fundamental equations. In addition, topics such as Earth system feedbacks and projections, decadal climate predictions, detection and attribution of climate change, evaluation of ESMs with observations, and climate informatics are covered. Selected areas of current research activities and results from ESMs are presented. The lecture includes computational exercises with the Earth System Model Evaluation Tool (ESMValTool, and interpretation of ESM results.

Topics to be addressed:

Components of Earth System Models (ESMs); Fundamentals and representation in ESMs: carbon cycle, atmospheric chemistry, and aerosols; Earth system feedbacks and projections; Decadal climate predictions; Detection and attribution of climate change; Earth system model evaluation with observations; Climate informatics; Results from ESMs; Computational exercises with the Earth System Model Evaluation Tool (ESMValTool, and interpretation of ESM results.


1. Brasseur & Jacob, Modeling of Atmospheric Chemistry, 2016
2. Gettelman & Rood, Demystifying Climate Models, 2016
3. Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report, 2013
4. Jacobson, Fundamentals of Atmospheric Modeling, 2005
5. McGuffie & Henderson-Sellers, A Climate Modelling Primer, 2013
6. World Meteorological Organization (WMO) / United Nations Environment Programme (UNEP)
Scientific Assessment of Ozone Depletion