On the state of reduced-complexity climate modelling
Reduced-complexity climate models are the most computationally efficient end of the climate model hierarchy. They are widely used in climate science research, particularly at the science-policy interface. However, unlike the Coupled Model Intercomparison Project (CMIP) that focuses on more comprehensive Earth System Models, there has never been a systematic intercomparison project targeted specifically at reduced-complexity climate models. In this PhD completion seminar, Zebedee Nicholls will introduce the Reduced-Complexity Model Intercomparison Project (RCMIP) and discuss the state of reduced-complexity climate modelling. Beyond the intercomparison and evaluation efforts of RCMIP, the thesis includes elements of reduced-complexity model development and application, both of which will be discussed. Zebedee will also offer suggestions on possible next steps for reduced-complexity climate modelling, based on his experiences performing each step in the development-evaluation-application cycle. The thesis provides new insights into the behaviour and performance of reduced-complexity climate models, particularly understanding of their limitations. These insights allow users of reduced-complexity climate models, most notably at the science-policy interface, to have greater confidence when interpreting results from reduced-complexity climate models.
Zebedee is a world-leading expert in reduced complexity climate model development. He is the only researcher to have contributed heavily to the development of both MAGICC and FaIR, the two reduced complexity climate models used for emissions scenario assessment in the IPCC’s Special Report on Global Warming of 1.5°C. Alongside Malte, he leads the Reduced Complexity Model Intercomparison Project (RCMIP), which performs standardised evaluation of reduced complexity climate models (see rcmip.org). He also led the development of a common resource for reduced complexity model calibration data based on ESM output (cmip6.science.unimelb.edu.au) and helped create the input greenhouse gas datasets for CMIP6’s future scenario experiments (greenhousegases.science.unimelb.edu.au). Before his PhD, Zebedee completed his undergraduate Masters course in Physics at St.John’s College, University of Oxford. Beyond his PhD and Climate Resource work, Zebedee is also a Contributing Author to Chapter 1 of Working Group 1 of the forthcoming IPCC Sixth Assessment Report.