We have entered a mass experiment for climate change. With remote working and the pandemic quickly squelching economic and social activities across the globe, global emissions have fallen by an estimated 6 per cent to 8 per cent last year - the largest drop in the century.

Cleaner air was celebrated across much of the world, the result of fewer buses, cars and trucks on the roads as well as airplanes in the skies - at least for a couple of months before pollution levels rose as economic activity resumed.