The air has been noticeably cleaner during the COVID-19 economic lockdown and now a group have scientists have computed the numbers to show why. Global greenhouse gas emissions declined by as much as 17 percent in April. Emissions dropped as much as 10 percent in the United States.
As world economies resume, the temporary decline in greenhouse gas emissions won’t be as pronounced, but scientists predict the year-to-year decline will still be somewhere between 4 and 7 percent. For context, the 2008 financial crisis resulted in only a 1.5 percent annualized reduction in global greenhouse gas emissions. The United Nations issued a report last year indicating an annual 7.6 percent reduction in greenhouse gas emissions beginning in 2020 would be needed to comply with commitments in the Paris Climate Accord.
The new data was contained in a peer-reviewed article published by Nature Climate Change. The authors note the lack of real-time CO2 emission data led them to devise an alternate method based on country-by-country confinement policies and time frames. Here are excerpts from the report:
“The changes in emissions are entirely due to a forced reduction in energy demand. Although in this case the demand disruption was neither intentional nor welcome, the effect provides a quantitative indication of the potential limits that extreme measures could deliver with the current energy mix (for example, a higher rate of home working or reducing consumption).
“The economic crisis associated with COVID-19 is markedly different from previous economic crises in that it is more deeply anchored in constrained individual behavior. At present it is unclear how long and deep the crisis will be, and how the recovery path will look, and therefore how CO2 emissions will be affected.”
The Washington Post story on the report observed the data show broad structural change in the energy, manufacturing and transportation sectors can “slash emissions in a meaningful, sustainable way.” The data also shows behavior change alone is not enough, according to Corinne Le Quéré, lead author of the study and director of Britain’s Tyndall Center for Climate Change Research.
Le Quéré said it was notable “many sources of carbon dioxide and other pollutants have continued steadily, almost on autopilot, even as much of the world has ground to a halt. Appliances continue to run, office buildings must be maintained and some factories continue to hum. There’s a lot of inertia in the infrastructure, in the built environment.”
Broad structural change in energy, manufacturing and transportation can slash emissions in a meaningful, sustainable way. But the data also shows behavior change is not enough to meet ambitious greenhouse gas reduction targets in the Paris Climate Accord.
That will require innovation.
The authors say the pandemic offers a climate change inflection point as governments invest to stimulate economic recovery. “Where they put this stimulus is really critical,” Le Quéré says. “It’s 2020, and there’s not much time to tackle climate change.”
Some European leaders have committed to make green investments to stimulate the economy while preserving the greenhouse gas emission reductions realized during the lockdown. British Prime Minister Boris Johnson recently told Parliament, “Inadvertently, the planet this year will [have] greatly reduced its CO2 emissions.… We need to entrench those gains. I don’t want to see us going back to an era of the same type of emissions as we’ve had in the past.”
Reductions in emissions have varied by nation and by sector. The Post reports aviation emissions declined by 60 percent, but they make up a significantly smaller portion of overall emissions than surface transportation, which logged only a 36 percent reduction. Industry emissions dropped by 19 percent and power plants by 7 percent, as residential emissions increased by 3 percent. The largest decline in emissions came in China, where the coronavirus originated. The next largest decline was in the United States, followed by Europe and India.
The report said, “Our study reveals how responsive the surface transportation sector’s emissions can be to policy changes and economic shifts. Surface transport accounts for nearly half the decrease in emissions during confinement, and active travel (walking and cycling, including e-bikes) has attributes of social distancing that are likely to be desirable for some time and could help to cut back CO2 emissions and air pollution as confinement is eased.”
It cited “Bogota, New York, Paris, Berlin and other cities that are rededicating street space for pedestrians and cyclists to enable safe individual mobility, with some changes likely to become permanent. Follow-up research could explore further the potential of near-term emissions reductions in the transport sector that could be delivered with minimal or positive impact on societal well-being.”