Abstract:
General circulation and Earth-system climate models that are used to make global climate projections are computationally expensive to run. Furthermore, as these models take time to develop and test, and intercomparison projects such as CMIP6 take several years to coordinate, simpler models have become an important tool in assessing climate responses to a broad pathway of emissions. A recent example is the IPCC Special Report on 1.5°C, where scientific assessments must be made with the available evidence in a short timeframe.
We have developed a simple open-source earth system model emulator, FaIR, which projects temperature responses as a function of input emissions and effective radiative forcing. FaIR can be tuned to simulate a particular model, where emissions and forcing relationships are based on emerging CMIP6 results and peer-reviewed literature following the IPCC's Fifth Assessment Report. Two distinct advantages of simple models, arising from their low resource demands, are (1) large probabilistic ensembles can be run where input parameters such as aerosol radiative forcing and climate sensitivity are varied to produce a range of plausible temperature projections for a given emissions pathway, and (2) unlike in CMIP6 where only a handful of future pathways are investigated, hundreds of future emissions pathways can be modelled such as will be done in the IPCC's Working Group 3 report on climate change mitigation, spanning the full range of plausible future climates. They find utility in being coupled to integrated assessment models of the population and economy, and are now being extended to report climate impacts and other metrics of interest beyond global mean temperature.
The IPCC Special Report on 1.5°C uncovered structural differences between FaIR and the MAGICC model which has more historical precedence. Given the importance of simple models for calculating policy-relevant metrics such as the remaining carbon budget consistent with Paris Agreement targets or the social cost of carbon, this has motivated an intercomparison exercise of simple models for the upcoming IPCC Sixth Assessment Report.
What is the Joint Oslo Seminar (JOS):
Atmospheric and climate sciences have a stronghold in Oslo among the four institutions University of Oslo, the Meteorological Institute, CICERO and NILU. This joint seminar invites renowned international experts to contribute to an informal series of lectures, meant to create interaction with the Oslo atmospheric and climate science community on recent highlights and analysis in the field. All seminars will be held on Thursdays (Noon -1pm) and lunch (sandwiches) will be served on a “first-come-first-served”-basis.