Publish: 25 February 2022

The global response to the COVID-19 pandemic has led to a sudden reduction of both GHG emissions and air pollutants. Here, using national mobility data, we estimate global emission reductions for ten species during the period February to June 2020.

By the time the World Health Organization declared COVID-19 (Scientifically referred to as the severe acute respiratory syn-drome-coronavirus 2 or SARS-COV-2) a pandemic on 11 March 2020, the virus had already spread from China to their Asian countries, Europe and the United States. As of 5 July 2020, cases have been identified in 188 countries or regions. This has led to unprecedented enforced and voluntary restrictions on travel and work. This in turn has led to reductions of both GHG emissions and air pollutants. Analysis of mobility data from Google and Apple shows that mobility declined by 10% or more during April 2020 in all but one of the 125 nations tracked. Mobility declined by 80% in five or more nations (Supplementary Fig). Associated declines in air pollution have been observed from satellite data from local ground-based observations. The large pollution declines are expected to be temporary as pollution levels are already returning to near-normal in part of Asia.

Here we build an estimate of emission changes in GHGs and air pollution due to the COVID-19 global restrictions during the period February-June 2020 and project these into the future. These emission changes are then used to make a prediction of the resultant global temperature response. We examine the temperature response of a direct recovery to pre-COVID-19 national policies and emission levels, and also explore responses where the economic recovery to COVID-19 is driven by a either a green stimulus package or an increase in fossil fuel use.

Emission trends

Bottom-up emission-trend analyses have traditionally relied on laborious collection of various energy-industry-related indicators and statistics from multiple sources. The unprecedented recent access to global mobility data from GOOGLE And APPLE gives a unique opportunity to compare trends across many countries with a con-sistent approach. We use these data to develop a new method of emission-trend analysis. The advantage over previous approaches is the possibility of near-real-time analysis, national granularity and a systematic consistent approach across nation and over time. The disadvantages are the loss of a direct connection between energy and emissions and the need to make assumptions about these relationships. These are also disadvantages over the short time history of the mobility data providers around their detailed methodologies and uncertainties.

Here we make a simple set of assumptions to deduce estimates of emissions change from the mobility data and test the estimates extensively against the approach of LE Quere er al. Full PDF link here: https://drive.google.com/file/d/1ZrUKY7z4GfUaJOdBy-GEl28JlLD7h9nx/view?usp=drivesdk

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