Global carbon emissions rebound close to pre-Covid levels

Global carbon emissions in 2021 are set to rebound close to pre-Covid levels, according to a major report into greenhouse gas levels in the atmosphere.

The latest Global Carbon Project report, involving scientists from the University of Reading, shows that fossil carbon emissions dropped by 5.4% in 2020 amid Covid lockdowns, but predicts an increase of 4.9% this year (4.1% to 5.7%) to 36.4 billion tonnes.

Emissions from coal and gas use are set to grow more in 2021 than they fell in 2020, but emissions from oil use remain below 2019 levels.

The research team, which also included the University of Exeter, the University of East Anglia, CICERO and Stanford University, say a further rise in emissions in 2022 cannot be ruled out if road transport and aviation return to pre-pandemic levels and coal use is stable.

The findings come as world leaders meet at COP26 in Glasgow to address the climate crisis and try to agree on a plan of action going forward.

'Disappointing, but sadly quite predictable'

Dr Patrick McGuire, a land surface processes computational scientist in the Department of Meteorology at the University of Reading and the National Centre for Atmospheric Science, who was part of the team running one of the supercomputer models for the report, said: “Going back to some sort of normal life after the Covid-19 lockdowns in 2020 has seen carbon emissions immediately leap back to close to their pre-Covid levels.

“This is disappointing and worrying, but also sadly quite predictable. It shows that carrying on as normal is not an option if we are to keep global temperature rise below the targets set.”

As well as Dr McGuire, fellow Reading meteorologist Dr Tristan Quaife also worked on this supercomputer model, the Sheffield Dynamic Global Vegetation Model (SDGVM), wherein they estimated how much carbon has been stored in the soil and vegetation for each month of each year since the year 1700. The SDGVM model was only one of the DGVM’s used in the study. Reading scientists have also contributed to the report in previous years.

The report – the 16th annual Global Carbon Budget – analysed emissions by the world’s major emitters, finding that 2021 emissions appear to return to pre-COVID trends of decreasing CO2 emissions for the United States and European Union and increasing CO2 emissions for India. For China, the response to the COVID-19 pandemic has sparked further growth in CO2 emissions, pushed by the power and industry sectors.

For the rest of the world taken as a whole, fossil CO2 emissions remain below 2019 levels.  Over the past decade, global CO2 net emissions from land-use change were 4.1 billion tonnes, with 14.1 billion tonnes CO2 emitted by deforestation and other land-use changes, and 9.9 billion tonnes CO2 removed by regrowth of forests and soil recovery.

Remaining carbon budget shrinks

Based on the findings, atmospheric CO2 concentration is projected to increase by 2.0 parts per million (ppm) in 2021 to reach 415 ppm averaged over the year, a lower growth compared to recent years due to La Niña conditions in 2021.

To have a 50% chance of limiting global warming to 1.5°C, 1.7°C and 2°C, the researchers estimate the remaining ‘carbon budget’ has now shrunk to 420 billion tonnes, 770 billion tonnes and 1,270 billion tonnes respectively – equivalent to 11, 20 and 32 years at 2021 emissions levels.

Professor Pierre Friedlingstein, of Exeter's Global Systems Institute, who led the study, said: "Reaching net zero CO2 emissions by 2050 entails cutting global CO2 emissions by about 1.4 billion tonnes each year on average. Emissions fell by 1.9 billion tonnes in 2020 – so, to achieve net zero by 2050, we must cut emissions every year by an amount comparable to that seen during Covid.

"This highlights the scale of the action that is now required, and hence the importance of the COP26 discussions."

The 2021 edition of the Global Carbon Project was published today (Thursday 4 November) as a preprint and is undergoing an open review in the journal Earth System Science Data.