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 (CO_2ff) emissions, because of its complete depletion in fossil fuel sources. Here, we present a study on the CO_2ff 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 CO_2ff emissions reduction from Eurasia (exclude China) and different parts in China during the COVID-19 lockdowns.