Tue 19 May 2020 – In the first peer-reviewed study of the drop in global carbon emissions during the Covid-19 lockdown, an analysis of six economic sectors during the period January to April shows aviation was the most impacted by the confinement. While responsible for 3% of global emissions, it accounted for a 10% decrease in the global total during the first four months of the pandemic. The study, which has just been published in the journal Nature Climate Change, shows that daily global emissions across sectors during the peak of the confinement measures in early April decreased by 17% – or 17 million tonnes (MtCO2) – compared to mean daily levels in 2019, dropping to levels last observed in 2006. Depending on the level of remaining worldwide restrictions and their duration, the researchers from the universities of East Anglia (UK) and Stanford (US) estimate a fall of 4 to 7 per cent in overall 2020 global emissions, the rate of decline needed annually to limit climate change close to a 1.5C warming, they point out.

The estimated total change in emissions from the pandemic amounts to 1,048 MtCO2 until the end of April, equivalent to a 8.6% decrease over January to April 2019. Carbon emissions from the aviation sector declined by around 60% during the period, the equivalent of approximately 1.7 MtCO2 per day.

The estimated decrease in daily fossil CO2 emissions from the severe and forced confinement of world populations at its peak are extreme and probably unseen before, says the paper.

“Population confinement has led to drastic changes in energy use and CO2 emissions. These extreme decreases are likely to be temporary though, as they do not reflect structural changes in the economic, transport, or energy systems,” commented Prof Corinne Le Quéré of the University of East Anglia, who led the analysis.

“The extent to which world leaders consider climate change when planning their economic responses post COVID-19 will influence the global CO2 emissions paths for decades to come.

“Opportunities exist to make real, durable, changes and be more resilient to future crises by implementing economic stimulus packages that also help meet climate targets, especially for mobility, which accounts for half the decrease in emissions during confinement.”

The authors warn that the rush for economic stimulus packages must not make future emissions higher by delaying new green deals or weakening emissions standards. They recommend reducing demand for aviation by supporting more local tourism and video conferencing for businesses.

Co-author Prof Rob Jackson of Stanford University and Chair of the Global Carbon Project added: “The drop in emissions is substantial but illustrates the challenge of reaching our Paris climate commitments. We need systemic change through green energy and electric cars, not temporary reductions from enforced behaviour.”

Commenting on the study, Cait Hewitt of the Aviation Environment Federation said: “With many of us having realised the benefits of video calls for keeping contact with work colleagues, demand for business flights is likely to remain low even as flights resume, and minimising travel by holidays close to home will feel like the right thing to do for many of us for some time to come. This is a great time for policymakers to focus on boosting local tourism and making sure polluting sectors such as aviation help pay for the green investments that are needed to build towards a clean and healthy future.”

Added Dan Rutherford, Aviation Director at the International Council on Clean Transportation (ICCT): “The study shows that airline emissions are particularly sensitive to behavioural change. Policies to curb frequent flying can be a win/win for public health and the environment while still allowing flights when we need them.”

The research received support from the Royal Society, the European Commission projects 4C, VERIFY and CHE, the Gordon and Betty Moore Foundation, and the Australian National Environmental Science Program.

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