Title: Climate responses to emissions reductions due to COVID-19
Abstract:
The worldwide dramatic responses to the COVID-19 pandemic, following China’s nationwide lockdown in late January 2020, have led to a large reduction in human activities and thusemissions of greenhouse gases (GHGs) and aerosols.This has also triggered research interest in the environmental and climate sciences community in understanding the impacts of these reductions. Observation-based and modeling studies have shown discernible impacts of COVID-19 lockdowns and restrictions on regional air quality and climate.By prescribingaerosol emission changes during the lockdown, back‐to‐work and post‐lockdown stages of COVID‐19 in a global climate model, Yang et al. (2020) show a surface warming effect over several continental regions of the Northern Hemisphere via aerosol-radiation and aerosol-cloud interactions. A dozenearth system models, including E3SM,participated in a coordinated model intercomparison (CovidMIP) to examine climate responses to short-term emissions reductions due to COVID-19 (Jones et al., 2021). Using E3SMv1, we performed 10 initial-condition ensemble simulationsthat impose a “two-year blip” forcing (i.e., two-year reductions in GHGs and aerosol emissions, starting in 2020 and reverting to the baseline SSP2-45 levels by the end of 2022). The 12 models agree on the reduced aerosol loading and associated increases in shortwave radiation at the surface. The global mean impact on surface air temperature and rainfall during 2020-2024 is small, butthere are interesting regional signals of changes in temperature andprecipitation.The CovidMIPinitial analysis and some highlights of E3SMv1 results will be discussedin this presentation.