A sky without vapour trails and roads without cars: during the early days of lockdown many hoped these were the signs of an overworked planet finally getting the chance to breathe. And indeed, a comprehensive report published by Nature backed up that gut feeling.
This first graphic below records how, in the first and widely locked-down part of this year, daily global emissions were a chunky 17 percentage points down on the same part of 2019. (Of course, the lockdown’s timing varied from country to country, but on average in those studied, the maximum drop was over a quarter.) And the greatest chunk of the overall drop came from “surface transport”—cars, trucks and freight vessels.
This is more a reflection of the sheer weight of road transport than anything else. In proportional terms, shown on the second chart, the drop in emissions from emptying the skies was more dramatic. Environmentalists are often particularly concerned with aviation, because the pattern has been for fast growth, projected to continue.
So some dramatic changes, but do they give real reason for hope? Unfortunately, scientists say, the drop will have a “negligible” effect unless it is made to stick. The one recent precedent for a big drop in emissions, the one that followed the financial crisis (chart three below), suggests they soon bounce back. Environmentalists are left hoping against hope that the unprecedented restrictions on movement this year will have been enough to break polluting habits for good.
