Climate response to emissions reductions due to COVID-19: Initial results from CovidMIP

With twelve Earth system models from the Coupled Model Intercomparison Project, Phase 6 (CMIP6) they performed coordinated experiments to investigate if effects of COVID-19-related changes in societal activity are visible in the climate system. These twelve models performed over 300 model simulations spanning both initial condition and model structural uncertainty and thereby offering an unprecedent opportunity for further focused research.

The authors show that the imprint of COVID-19-induced changes in emissions is visible in atmospheric composition – notably aerosol optical depth over southern and eastern Asia, and in the amount of solar radiation reaching the planet’s surface. However, despite these changes in the make-up of the atmosphere, no detectable change in surface temperatures or rainfall could be found. They conclude that the emissions reductions were too small in magnitude and time to have a significant effect on global climate, and that larger, sustained changes on a longer timescale are required to have detectable effects. The authors recommend that both, a further focus on the regional analyses, and a detailed analysis of extremes are required to test the impacts of COVID-19-related emission reductions on near-term climate.