The near global shutdown brought about by the COVID-19 pandemic resulted in a steep but fleeting drop in the world’s carbon dioxide emissions, according to new research.
The greatest reduction in emissions came in early April, when daily global carbon emissions were down 17 percent compared to 2019, report Chris Mooney, Brady Dennis and John Muyskens for the Washington Post.
The study, published this week in the journal Nature Climate Change, estimates that the precipitous drop could translate to a reduction in total emissions of 4 to 7 percent for 2020, depending on how swiftly global activity resumes.
The larger, seven percent drop in carbon emissions for 2020 is what the researchers predict should happen if some restrictions on travel and economic activity continue through the end of the year.
The dramatic measures aimed at tamping down the deadly coronavirus begin to approximate the emissions cuts the world would need to make every year for a decade in order to meet the goals of the 2015 Paris climate agreement and stave off the worst consequences of climate change, reports the Post. A 2019 United Nations report calculated that the world would need to reduce carbon emissions by 7.6 percent every year until 2030 in order to meet the Paris goal of limiting warming to 1.5 degrees Celsius by 2100.
The unprecedented reduction in greenhouse gas emissions brought about by COVID-19 may approximate the scale of what scientists say is required to tackle climate change, but it’s not particularly informative about how humanity might get there.
Rob Jackson, an environmental scientist at Stanford University and co-author on the study, tells Carolyn Gramling of Science News that these reductions come at a huge cost, making them unsustainable and, as a result, temporary.
“Globally, we haven’t seen a drop this big ever, and at the yearly level, you would have to go back to World War II to see such a big drop in emissions,” Corinne Le Quéré, a climate scientist at the University of East Anglia and lead author of the study, tells Denise Chow of NBC News. “But this is not the way to tackle climate change — it’s not going to happen by forcing behavior changes on people. We need to tackle it by helping people move to more sustainable ways of living.”
Figuring out how steeply greenhouse gas emissions had plunged amid the pandemic was a challenge for Le Quéré and her co-authors because emissions are typically reported annually. To zoom in to the scale of days, weeks and months, the researchers used a variety of data sources, including daily electricity demand, city congestion and the numbers from home smart meters to estimate emissions in 69 countries, reports Science News. The researchers combined those data with what they call a “confinement index” that quantifies the lockdown measures enforced by various governments over time.
During the strictest levels of confinement, the analysis found aviation activity declined by 75 percent, ground transportation went down 50 percent, industry shrank by 35 percent and activity in the power sector (which includes energy used to generate electricity and heat) fell around 15 percent.
“Unless anything structurally changes, we can expect emissions to go back to where they were before this whole thing happened,” Zeke Hausfather, a climate scientist at the University of California, Berkeley, who was not involved with the new study, tells the Post.
For the last decade, humanity’s yearly greenhouse gas emissions have increased by an average of roughly 1 percent each year. From 2000 to 2010, that average increase was 3 percent a year. A single year of reduced emissions isn’t enough to make much of a dent in the amount of carbon dioxide lingering in the atmosphere.
“Carbon dioxide stays in the atmosphere for a very long time, so climate change is driven more by the total amount we’ve ever emitted than any amount we emit in a single year,” Hausfather tells NBC News. “From a climate standpoint, what really matters is long-term systemic changes that can drive emission declines over decades.”
Underscoring this point, the planet’s atmospheric concentrations of carbon dioxide reached roughly 418 parts per million this month, setting a new record for the highest concentration of the planet-warming gas ever recorded in human history, reports Alejandra Borunda for National Geographic.
An analysis from CarbonBrief earlier in May, suggests that without the decline in emissions from the coronavirus pandemic the overall concentration of carbon dioxide in the atmosphere would be just 0.4 parts per million higher.
The pandemic is not a win for climate change, but neither is it a signal that humanity’s hopes of rising to the challenge posed by the climate crisis are lost.
“A pandemic is the worst possible way to reduce emissions. There’s nothing to celebrate here,” Constantine Samaras, a climate expert at Carnegie Mellon University, tells National Geographic. “We have to recognize that, and to recognize that technological, behavioral, and structural change is the best and only way to reduce emissions.”