2020-12-02 | Bo Zheng
On 2 December, the MEIC team published a research article entitled “Satellite-based estimates of decline and rebound in China’s CO₂ emissions during COVID-19 pandemic” in the journal of Science Advances. Changes in CO₂ emissions during the COVID-19 pandemic have been estimated from indicators on activities like transportation and electricity generation. Here, we instead use satellite observations together with bottom-up information to track the daily dynamics of CO₂ emissions during the pandemic. Unlike activity data, our observation-based analysis can be independently evaluated and can provide more detailed insights into spatially-explicit changes. Specifically, we use TROPOMI observations of NO₂ to deduce ten-day moving averages of CO₂ emissions over China. The total reduction in China’s CO₂ emissions over January–April 2020 is equivalent to a −11.5% decrease over the corresponding period of 2019. The largest emission reductions occurred in February, while the emissions rapidly rebounded in March and April, and the CO₂ emissions in April 2020 are estimated +2.7% higher than that in 2019.
The sharper emission declines in 2020 started on 20th January 2020, when the most stringent control measures were activated by the National Health Commission. The Wuhan lockdown began three days later on 23rd January 2020, which was followed by similar measures in the other Chinese cities within the next few days. These lockdown measures did not ease until about one month later when the lowest-risk regions and cities slowly reopened some of the less exposed industries and businesses. About two months after the Chinese New Year 2020, most of China’s cities had lifted the control measures including Wuhan that reopened on 8th April after a 76-day lockdown. During the Wuhan lockdown period, China’s emissions were lower than the 2019 emissions by a cumulative of 348 Mt CO₂ (16.2% net reduction).