LAST YEAR’S clear spring skies foreshadowed it and the numbers bear it out: covid-19 lockdowns caused a sharp drop in emissions from burning fossil fuels, the largest such drop since the second world war. The latest data, published on March 3rd by the Global Carbon Project, an international consortium of climate researchers, puts industrial carbon-dioxide emissions produced in 2020 at 34bn tonnes, 2.6bn tonnes (7%) lower than in 2019.

Clearly, 2020 was an unusual year and emissions have already started to rebound. What is more, the drop came at a huge cost to economies and societies. Yet, in order to meet the Paris agreement’s goal of limiting global warming to between 1.5°C and 2°C above pre-industrial levels, more big cuts will be needed for the rest of the decade. “We need a cut in emissions of about the size of the fall [from the pandemic] every two years, but by completely different methods,” said Corinne Le Quéré, of the University of East Anglia, one of the lead researchers on the study.

Global emissions were starting to turn a corner before covid-19. After decades of rapid growth, the year-on-year rise was showing signs of slowing (see chart). Between 2016 and 2019, in the aftermath of the Paris agreement, emissions dropped in 64 countries compared to the previous five-year period, although they rose in 150 others. On average, the 64 cut a cumulative 0.16bn tonnes of CO2 per year during that period—one-tenth of what is needed globally to meet the Paris goals.

The inescapable conclusion is that much, much more is needed. Ahead of this November’s COP26 UN climate summit, countries are required to put forward new, more ambitious pledges to cut emissions. So far 75 have done so, representing some 30% of global emissions. More than 100 are outstanding. A report issued by the UN Framework Convention on Climate Change, published on February 26th, found that, if carried out, the pledges that have already been submitted would cut global emissions by 1% by 2030, compared to where they were in 2010. Depressingly, climate models show that to meet the 2°C goal, this number needs to be closer to 25%, or 45% for the more ambitious 1.5°C goal.