Decrease in fossil fuel CO2 emissions during COVID-19 lockdowns based on  Δ14CO2 observation

Radiocarbon can be used as an independent and objective tracer to evaluate fossil fuel CO2 (CO2ff) emissions, because of its complete depletion in fossil fuel sources. Here, we present a study on the CO2ff emissions reduction during the COVID-19 lockdowns in 2020 based on atmospheric Δ14CO2 observation at Chinese background sites. We observed obvious enhancements (several per mill to dozens of per mill) of atmospheric Δ14CO2 during the COVID-19 lockdowns compared with that in the same period. A preliminary analysis showed that these enhancements indicate several percepts to dozens of percents CO2ff emissions reduction from Eurasia (exclude China) and different parts in China during the COVID-19 lockdowns.