Earth’s energy imbalance trend strengthened by recent aerosol emission reductions

The Earth’s energy imbalance (EEI) is the difference in the net solar radiative flux and outgoing longwave radiative flux at the top-of-atmosphere. It has been shown that the positive EEI trend in the previous two decades is unexplained by internal variability and caused by anthropogenic forcing and response, such as that resulting from anthropogenic CO₂ emissions. In this work we apply two state-of-the-art global climate models, the CESM2 and ICON-HAM, forced with observed (evolving) sea-surface temperature fields for the period 2000-2019 and with multiple ensemble members, to explore causes for the positive trend in EEI. Both models are able to reproduce the observed EEI trend from the CERES satellite product relatively well. Sensitivity simulations with aerosol emissions kept constant at year 2000 values indicate a relatively strong influence of recent aerosol emission reductions on the EEI trend. Preliminary results further indicate a considerable effect of using the latest CEDS emission version, as opposed to the CMIP6 CEDS version, on the EEI trend.