Climate model emulation in an integrated assessment framework: a case study for mitigation policies in the electricity sector.

We present a carbon cycle-climate modelling framework using model emulation, designed for integrated assessment modelling, which introduces a new emulator of the carbon cycle (GENIEem). We demonstrate that GENIEem successfully reproduces the CO₂ concentrations of the Representative Concentration Pathways when forced with the corresponding CO₂ emissions and non-CO₂ forcing. To demonstrate its application as part of the integrated assessment framework, we use GENIEem along with an emulator of the climate (PLASIM-ENTSem) to evaluate global CO₂ concentration levels and spatial temperature and precipitation response patterns resulting from CO₂ emission scenarios. These scenarios are modelled using a macroeconometric model (E3MG) coupled to a model of technology substitution dynamics (FTT:Power), and represent different emissions reduction policies applied solely in the electricity sector, without mitigation in the rest of the economy. The effect of cascading uncertainty is apparent, but despite uncertainties, it is clear that in all scenarios, global mean temperatures in excess of 2 °C above preindustrial levels are projected by the end of the century. Our approach also reveals the diverse temperature and precipitation patterns that could occur regionally in response to the global mean temperatures associated with these scenarios, enabling more robust impacts modelling and emphasising the necessity of focussing on spatial patterns in addition to global mean temperature change. [ABSTRACT FROM AUTHOR]