Fabio Panetta May 12, 2021 09:05 The COVID-19 pandemic has caused the largest decrease in global economic activity on record. But the drop in carbon dioxide emissions has been only temporary. Although global CO2 emissions fell by 6.4% overall in 2020, they had already begun to increase in the second half of the year and have now returned to pre-crisis levels. The fact that last year’s extraordinary circumstances still did not bring global emissions into line with the targets set by the 2015 Paris climate agreement is a stark reminder of the scale of the challenge we face. As the Nobel laureate economist William Nordhaus reminds us, climate change is the quintessential global externality. Its effects are spread around the world and no country has sufficient incentives or capacity to solve the problem on its own. International coordination is therefore essential.