FaIR – Finite Amplitude Impulse Response
- Initial Release:2017
- Institution(s):Atmospheric, Oceanic, and Planetary Physics, Department of Physics, University of Oxford, ; Australian–German Climate and Energy College, University of Melbourne; School of Geography, Earth and Atmospheric Sciences, University of Melbourne; School of Earth and Environment, University of Leeds; International Institute for Applied Systems Analysis; Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry; Environmental Change Institute, University of Oxford.
- Referent:Nicholas J. Leach
The Finite Amplitude Impulse Response (FaIR) model is a simple emissions-based climate model. It allows the user to input emissions of greenhouse gases and short lived climate forcers in order to estimate global mean atmospheric GHG concentrations, radiative forcing and temperature anomalies. The original FaIR model (v1.0) was developed to simulate the earth system response to CO2 emissions, with all non-CO2 forcing implemented as an “external” source. FaIRv2.0.0 is an update which aims to significantly increase the structural simplicity of the model, making it more understandable and transparent. FaIRv2.0.0 can be implemented in a wide range of environments, including Excel.
The model is based on a set of six equations, five of which correspond to the standard impulse response model used for greenhouse gas (GHG) metric calculations in the IPCC’s Fifth Assessment Report, plus one additional physically motivated equation to represent state-dependent feedbacks on the response timescales of each greenhouse gas cycle. This additional equation is necessary to reproduce non-linearities in the carbon cycle apparent in both Earth system models and observations.