Understanding uncertainties in the global Earth climate response with reduced complexity climate models

Simple climate models provide a flexible, computationally cost-effective way to emulate the more complex and higher resolution earth system models. As ESMs are improved, adding in new processes that weren't explicitly included before, so too can the simple climate models be refined to reflect changes to our understanding of the climate response to changing emissions. New developments in modelling of peatlands, wetlands, permafrost, and negative emissions scenarios have provided new data to test the simple models MAGICC and FAIR. By comparing their projections under the same scenarios used by more complex models, the reduced complexity models' limitations and uncertainties can be shown, and thus they can be improved to better capture the new knowledge. Here, we focus on peatlands, comparing the results of a new module in the model OSCAR with the current output from MAGICC and FAIR, quantifying the impact that explicit peatland processes have on global temperature. Negative emissions scenarios are also considered, all as part of a broader project to understand overshoot pathways, scenarios in which the global temperature anomaly exceeds 1.5°C but returns to a temperature below that mark. These results will show the value and capability of the simple climate models as they continue to be refined to emulate the larger models.