Abstract
The effect of anthropogenic aerosols on lightning is one of the least
understood aspects of human-induced climate change. Global aerosol
clearly diminished during the COVID pandemic by 7.6%. A pronounced
decrease in global lightning activity in the range 3.0%-5.8% is
identified from various detection systems during this natural
experiment. The Maritime Continent lightning chimney shows the largest
reduction of 7.0% in aerosol accompanied by a lightning drop of 15%.
The COVID period in 2020 also experiences a transition from pre-COVID El
Niño to a strong and sustained La Niña. Compensation for ENSO forcing of
lightning activity is implemented to disclose the distinct responses of
three global lightning chimneys to competing thermodynamic and aerosol
effects. Our observational findings indicate a marked influence of
aerosol on a global scale by virtue of the extraordinary COVID-induced
aerosol alteration.