Lockdowns led to historic drops in our CO2 emissions

The year 2020 has proved disastrous worldwide for a number of reasons owing largely to the ongoing COVID-19 pandemic. Yet there has been a silver lining in all the months-long shutdowns aimed at containing the spread of the novel coronavirus from Wuhan: a significant drop in carbon emissions.

During the first six months of the year, say scientists, we emitted 8.8% less carbon dioxide globally than during the same period last year in what amounted to a total decrease of 1,551 million tons.

Not even during the financial crisis of 2008 or the oil crisis of the 1979 was there such a precipitous drop in CO2 emissions, according to the authors of a new study. “The magnitude of this decrease is larger than during previous economic downturns or World War II,” the researchers explain.

The scientists examined daily figures compiled by the Carbon Monitor research initiative to see how emissions decreases corresponded to lockdown measures in each country around the planet. They perused hourly datasets of electricity power production in 31 countries, daily vehicle traffic in more than 400 cities worldwide, daily global passenger flights, monthly production data for industry in 62 countries as well as fuel consumption data for building emissions in more than 200 countries.

They found that there was an especially large drop in CO2 emissions from transportation as citywide lockdowns and severe travel restrictions took effect. As domestic and international travel shrank to a minimum, the carbon footprint of various forms of transportation shrank in tandem, including that of ground transportation and global aviation, the latter of which produces around 2% of annual global emissions.

“The greatest reduction of emissions was observed in the ground transportation sector. Largely because of working from home restrictions, transport CO2 emissions decreased by 40% worldwide,” explains Prof. Daniel Kammen, a scientist at the University of California, Berkeley.

“In contrast, the power and industry sectors contributed less to the decline, with -22 % and -17 %, respectively, as did the aviation and shipping sectors,” Kammen adds. “Surprisingly, even the residential sector saw a small emissions drop of 3 %: largely because of an abnormally warm winter in the northern hemisphere, heating energy consumption decreased with most people staying at home all day during lockdown periods.”

In April alone, as lockdowns were instituted to limit the spread of coronavirus infections, CO2 emissions declined by 16.9%. “Overall, the various outbreaks resulted in emission drops that we normally see only on a short-term basis on holidays such as Christmas or the Chinese Spring Festival,” explains Zhu Liu, an expert at the Department of Earth System Science at Tsinghua University in Beijing who worked on the study.

Yet by July, as severe lockdown measures had been lifted or were being lifted worldwide, most countries resumed their usual rates of CO2 emissions.

Yet shutting down normal human activities, as happened during the first half of 2020, is hardly the answer to reducing our global emissions long-term as doing so would lead to prolonged misery and economic hardships for billions of people. “While the CO2 drop [was] unprecedented, decreases of human activities cannot be the answer,” stresses Hans Joachim Schellnhuber, director of the Potsdam Institute for Climate Impact Research.

“Instead we need structural and transformational changes in our energy production and consumption systems. Individual behavior is certainly important, but what we really need to focus on is reducing the carbon intensity of our global economy,” Schellnhuber explains.