Global carbon emissions from using fossil fuels fell by a record amount in 2020 as a result of Covid-19 lockdowns around the world, researchers have said.

They warned, however, that greener measures are needed as economies recover, including boosting cycling, walking and electric cars in the UK, to start delivering the annual emissions cuts required to to curb climate change.

The UK saw one of the biggest drops in emissions at 13%, the analysis suggests, as it saw major reductions in transport – the largest source of climate pollution for the country – and was hit by two waves of restrictions.

Worldwide, carbon emissions from burning coal, gas and oil for power and transport, from manufacturing cement and from industrial processes fell by a record 2.4 billion tonnes, a 7% drop on 2019 levels.

Transport made up the biggest share of falling emissions as car journeys were reduced and aviation was halted, researchers at the University of East Anglia (UEA), University of Exeter and the Global Carbon Project said.

In December 2020, global emissions from road transport were still 10% below 2019 levels and aviation pollution was 40% lower than last year.

The overall fall is much larger than in the economic downturn in 2009, and comes on top of faltering growth in carbon emissions in recent years, which could be partly due to climate policies by countries, the team said.

Emissions are expected to rise again in 2021 because the fall was so large this year, but it too early to say how much pollution will rebound as the world comes out of the pandemic, they said.

Emissions from industry could already be up to or above 2019 levels, and stimulus efforts by many governments have focused on existing sectors rather than new green technology and measures, although the UK is among those doing better on that front.

Sustained cuts of 1-2 billion tonnes in annual carbon dioxide emissions are needed every year this decade to curb temperature rises, the researchers warn.

Prof Corinne Le Quere, from UEA, said: “All elements are not yet in place for sustained decreases in global emission, and emissions are slowly edging back to 2019 levels.

“Government actions to stimulate the economy at the end of the Covid-19 pandemic can also help lower emissions and tackle climate change.”

We are in a unique position now, not only because of the Covid-19 pandemic, but because of pre-existing climate policies, new green deals and net zero commitments

In the UK, action on transport would help limit increase in emissions in the coming years, she said.

“Stopping the rebound now would have to be done with encouraging walking and cycling and electric bikes if you want to do it quickly by 2021, and longer term, it’s about electric mobility,” she said.

The US saw emissions drop by around 12% and in the EU27 there was an 11% drop, the research published in the journal Earth System Science Data showed.

But in China, where Covid-19 restrictions occurred and were removed earlier in the year and which came on top of rising emissions, the estimated reduction was just 1.7%.

Overall, carbon emissions from both fossil fuel burning and the way land is used, mostly from deforestation offset by vegetation re-growing on abandoned agricultural land, were 39 billion tonnes in 2020, the researchers estimate.

They have to fall to zero overall in the next few decades to meet targets under the international Paris Agreement to limit temperature rises to well below 2C (3.6F) above pre-industrial levels and to pursue efforts to curb them to 1.5C (2.7F) to prevent the worst impacts of climate change.

Lead researcher Prof Pierre Friedlingstein, of the University of Exeter, said: “We are in a unique position now, not only because of the Covid-19 pandemic, but because of pre-existing climate policies, new green deals and net zero commitments.

“Countries responsible for 50-60% of global emissions are committed to net zero, and there will be large economic stimuluses being produced.

“All of this combined is a unique opportunity to actually tackle and break this long term emissions in carbon dioxide and therefore climate change.

“There’s hope, but of course, action needs to be taken and followed,” he said.