During the most intense period of forced confinement in early 2020, daily global CO2 emissions may have been reduced by up to 17% compared to the mean level of daily CO2 emissions in 2019. As the duration and severity of the confinement measures remain unclear, it is very difficult to predict the total annual reduction in CO2 emissions for 2020; however, preliminary estimates anticipate a reduction of between 4.2% and 7.5% compared to 2019 levels.
At the global scale, an emission reduction of this magnitude will not cause atmospheric CO2 levels to decrease; they will merely increase at a slightly reduced rate, resulting in an anticipated annual atmospheric CO2 concentration that is 0.08 ppm–0.23 ppm lower than the anticipated CO2 concentration if no pandemic had occurred. This falls well within the 1 ppm natural inter-annual variability and means that in the short-term, the impact of COVID-19 confinement measures cannot be distinguished from natural year-to-year variability. …
A depressing report despite this additional (questionable?) conclusion:
“The needed changes are economically affordable and technically possible and would affect our everyday life only marginally. It is to be welcomed that a growing number of countries and companies have committed themselves to carbon neutrality. There is no time to lose.”