The global response to the Covid-19 pandemic has driven the biggest annual fall in CO2 emissions since World War Two, say researchers.
Their study indicates that emissions have declined by around 7% this year.
France and the UK saw the greatest falls, mainly due to severe shutdowns in response to the second wave of infections.
China, by contrast, has seen such a large rebound from coronavirus that overall emissions may grow this year.
The decline in carbon in 2020 has dwarfed all the previous big falls.
Overall, the research team estimates that the country will experience a fall in emissions of 1.7% this year but some analysis suggests that the country has already rebounded enough from Covid-19 that the overall carbon output may have increased.
“All our datasets show that China experienced a big drop in emissions in February and March, but the datasets differ in the level of emissions towards the end of 2020,” said Jan Ivar Korsbakken, a senior researcher at CICERO, who was involved in the study.
“In late 2020, China is at least close to having the same level of daily emissions as in 2019, and indeed some of our estimates suggest Chinese emissions may have actually increased for the year as a whole in 2020 relative to 2019, despite the pandemic,” he added.
Researchers believe that dramatic drop experienced through the pandemic response might be hiding a longer term fall-off in carbon, more related to climate policies.
The annual growth in global CO2 emissions fell from around 3% in the early years of this century to around 0.9% in the 2010s. Much of this change was down to a move away from coal as an energy source.
“An emerging discussion pre-2020 was whether global fossil CO2 emissions were showing signs of peaking,” said Glen Peters, research director at CICERO.
“Covid-19 has changed this narrative to one that involves avoiding a rebound in emissions and asking if emissions have already peaked,” he said.
All the researchers involved in this project agree that a rebound of emissions in 2021 is almost certain.
To minimise the uptick in carbon, the scientists are urging a “green” rather than a “brown” response, meaning recovery funding should be spent on sustainable projects and not on fossil fuels.
They argue that efforts should also be made to boost walking and cycling in cities and to rapidly deploy electric vehicles.