Stanford University
Carbon simulation

COVID lockdown causes record drop in carbon emissions for 2020

Carbon dioxide emissions from oil, gas and coal this year are predicted to reach approximately 34 billion tons, a 7 percent drop from fossil emission levels in 2019. Emissions from transport account for the largest share of the global decrease.

BY University of East Anglia and University of Exeter Communications
ClockDecember 10, 2020

The global COVID-19 lockdowns caused fossil CO2 emissions to decline by an estimated 2.4 billion tonnes in 2020 - a record drop according to new estimates from researchers at the University of East Anglia (UEA), University of Exeter and the Global Carbon Project, an initiative chaired by Stanford University scientist Rob Jackson.

The estimates, to be published Dec. 11 in the journal Earth System Science Data, show a considerably larger decline compared to even the steepest emission decreases seen over much of the past century: 0.5 billion tonnes of CO2 (GtCO2) in 1981 and 2009; 0.7 GtCO2 in 1992; and 0.9 GtCO2 in 1945 at the end of World War II. Carbon emissions from the burning of fossil fuels such as oil and gas are predicted to be approximately 34 GtCO2, 7 percent lower than in 2019.

"A drop of almost two and a half billion tons of CO2 this year is like taking 500 million cars off the world’s roads for the year. Good things are happening as more states and countries make ambitious climate commitments and real progress.” said Jackson, a professor of Earth system science in Stanford’s School of Earth, Energy & Environmental Sciences (Stanford Earth), “However, we need to reduce emissions more sustainably when economies and people are healthy. Green stimulus funding is a key to further progress.”

This animation shows the atmosphere as a "bucket" filling with greenhouse gas pollution from fossil fuel use, from 1870 to 2020.

Emissions from transport account for the largest share of the global decrease. Those from surface transport, such as car journeys, fell by approximately half at the peak of the COVID lockdowns. By December 2020, emissions from road transport and aviation were still below their 2019 levels, globally by approximately 10 percent and 40 percent, respectively, due to continuing restrictions.

Los Angeles freeway
An empty Los Angeles freeway during the coronavirus pandemic. (Image credit: iStock)

Total CO2 emissions from human activities – from fossil CO2 and land-use change – are set to be approximately 39 GtCO2 in 2020.

The release of this year’s Global Carbon Budget comes ahead of the five-year anniversary of the Dec. 12 adoption of the UN Paris climate Agreement, which aims to reduce the emission of greenhouse gases to limit global warming. Cuts of around 1 to 2 GtCO2 are needed each year on average between 2020 and 2030 to limit climate change in line with its goals.  

Five years on from the landmark agreement, the researchers say growth in global CO2 emissions had begun to falter, with emissions increasing more slowly in recent years, which could be partly in response to the spread of climate policies. For the decade prior to 2020, fossil CO2 emissions decreased significantly in 24 countries whose economies continued to grow.

However, the researchers warn that it is too early to say how much emissions will rebound during 2021 and beyond, as the long-term trend in global fossil emissions will be largely influenced by actions to stimulate the global economy in response to the COVID-19 pandemic.

Corinne Le Quéré, Royal Society Research Professor at UEA’s School of Environmental Sciences, contributed to this year’s analysis. “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,” she said.

“Incentives that help accelerate the deployment of electric cars and renewable energy and support walking and cycling in cities are particularly timely given the extensive disturbance observed in the transport sector this year,” Le Quéré added.

The emissions decrease appears more pronounced in the United States (-12 percent) and EU27 countries (-11 percent), where COVID-19 restrictions accelerated previous reductions in emissions from coal use for electricity. It appears least pronounced in China (-1.7 percent), where the effect of COVID-19 restrictions on emissions occurred on top of rising emissions. In addition, restrictions in China occurred early in the year and were more limited in duration, giving the economy more time to recover.

“If emissions roar back when economies recover,” said Jackson, who is a senior fellow at Stanford’s Woods Institute for the Environment and Precourt Institute for Energy, “this year’s decrease will mean little in the march to net-zero carbon emissions.”

In the United Kingdom, which first introduced lockdown measures in March, emissions are projected to decrease about 13 percent. The large decrease in UK emissions is due to the extensive lockdown restrictions and the second wave of the pandemic.

In India, where fossil CO2 emissions are projected to decrease about 9 percent, emissions were already lower than normal in late 2019 because of economic turmoil and strong hydropower generation, and the COVID-19 effect is superimposed on this changing trend.

For the rest of the world the effect of COVID-19 restrictions occurred on top of rising emissions, with emissions this year projected to decrease by about 7 percent.

Globally, the peak decrease in daily emissions in 2020 occurred in the first half of April, when lockdown measures were at their maximum, particularly across the U.S. and Europe.

Emissions from industrial sources such as metal production, chemicals and manufacturing, declined by up to a third during the COVID-19 lockdown in spring. However, they could already be back up to near or even above 2019 levels by now. 

Despite lower emissions in 2020, the level of CO2 in the atmosphere continues to grow – by about 2.5 parts per million (ppm) in 2020 – and is projected to reach 412 ppm averaged over the year, 48 percent above pre-industrial levels.

Although global emissions from fossil fuels and deforestation were not as high as last year, “they still amounted to about 39 billion tonnes of CO2, and inevitably led to a further increase in CO2 in the atmosphere,” said lead researcher Prof Pierre Friedlingstein, of the University of Exeter. “The atmospheric CO2 level, and consequently the world’s climate, will only stabilize when global CO2 emissions are near zero.”

Preliminary estimates based on fire emissions in deforestation areas indicate that emissions from deforestation and other land-use change for 2020 are similar to the previous decade, at around 6 GtCO2. Approximately 16 GtCO2 was released, primarily from deforestation, while the uptake of CO2 from regrowth on managed land, mainly after agricultural abandonment, was just under 11 GtCO2. Measures to better manage land could both halt deforestation and help increase the CO2 sink from regrowth.

Deforestation fires were lower this year compared to 2019 levels, which saw the highest rates of deforestation in the Amazon since 2008. In 2019 deforestation and degradation fires were about 30 percent above the previous decade, while other tropical emissions, mainly from Indonesia, were twice as large as the previous decade because unusually dry conditions promoted peat burning and deforestation.

Land and ocean carbon sinks continue to increase in line with emissions, absorbing about 54 percent of the total human-induced emissions.

Jackson is also the Michelle and Kevin Douglas Provostial Professor at Stanford.

This story was adapted from a press release issued by the University of East Anglia and University of Exeter.

Media Contacts

Rob Jackson

Department of Earth System Science

(650) 497-5841; rob.jackson@stanford.edu

UEA Communications Office

communications@uea.ac.uk

University of Exeter Press Office

+44 (0)1392 724828; pressoffice@exeter.ac.uk

Josie Garthwaite

School of Earth, Energy & Environmental Sciences

(650) 497-0947; josieg@stanford.edu

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