Regional Impacts of COVID-19 on Carbon Dioxide Detected Worldwide from Space.

Monitoring the global distribution of greenhouse gases using spaceborne observations and attributing regional anomalies of their surface fluxes to either climatic or human processes represents a new frontier in Earth system science. The reduction in economic activity in early 2020 due to the Coronavirus Disease 2019 (COVID-19) pandemic led to unprecedented decreases in monthly carbon dioxide (CO2) emissions from fossil fuel use. This paper shows, for the first time, that the regional impact of COVID-19 was observable from space. Our approach uses data assimilation to ingest satellite observations of column average CO2 (XCO2) from NASA's Orbiting Carbon Observatory 2 (OCO-2) into the Goddard Earth Observing System (GEOS), an integrated Earth system model.