As people around the world faced forced confinements caused by the COVID-19 pandemic, global greenhouse gas emissions fell as a result. A study led by climate scientist Corinne Le Quéré of the University of East Anglia published in the journal Nature estimated that emissions fell by 8% compared with 2019 levels. That drop brought emissions in line with their 2006 level. The researchers estimated that total 2020 emissions would fall by between 4 and 7% compared to last year. However, with communities reopening around the world, carbon emissions have begun to return, ticking back up to just 5% below 2019 levels.
At the height of lockdowns across the world, emissions from almost every industry fell drastically. Transportation over land, sea, and air ground to a halt as did factories and commercial buildings. The world used less coal, oil, and natural gas to generate power though residential emissions climbed modestly. Despite recent rebounds in emissions, the world economy is clearly nowhere near fully recovering from the effects of the pandemic. 2020 will likely see an unprecedented decrease in global emissions compared to 2019. In fact, even a 5% drop would be the largest since World War II. Even if post-pandemic economies pollute at the same rate as they did before the pandemic, 128 gigatonnes of carbon dioxide less will have entered the atmosphere, resulting in a difference of 10 parts per million, or three years of emissions at 2018 levels.
However, as countries begin to emerge from confinement, the methods they use to recover from the pandemic economically will shape the future of climate change. Whether the word recovery is green or carbon intensive could mean a difference of 19 parts per million carbon dioxide in the atmosphere. Countries including the US have begun to relax fuel efficiency standards for vehicles, committing them to higher emissions levels in the future.
Incredibly, the drop in emissions caused by the pandemic are roughly equivalent to that required to keep global temperatures from rising by the 1.5 degrees celsius agreed upon in the Paris Climate Agreement. In other words, to avoid hitting the 1.5 degrees mark, the global emissions drop created by the global health catastrophe would have to be repeated each year for the next decade.