Figure 1

(a) Crude oil WTI price from January to July 20208. Note the sudden and unprecedented negative price in April 2020. (b) Total number of flights tracked by FlightRadar24 from January to July 20209. At the end of March there was an abrupt decrease of the number of flights (\(\sim\) 100,000 units) because of the lockdown restrictions. (c) Daily navigated miles by passenger ships in 2020 compared with 2019.