Coronavirus crisis leads to 17% drop in global carbon emissions, study says

The world cut its daily carbon dioxide emissions by 17% at the peak of the coronavirus-induced shutdown last month, according to a new study.

But with life and heat-trapping gas levels inching back toward normal, the brief pollution break will likely be “a drop in the ocean” when it comes to climate change, scientists said.

Pollution levels for the full year will end up between 4% and 7% below 2019 levels, according to the study published Tuesday in the journal Nature Climate Change

The 7% forecast is for a scenario where the strictest coronavirus lockdown rules remain in place all year across much of the globe; if they are lifted sooner, the reduction would be closer to 4%.

Either way, it will be the biggest annual drop in carbon emissions since World War II, the scientists said.

For a week in April, the United States cut its carbon dioxide levels by about one-third. China, the world’s biggest emitter of heat-trapping gases, sliced its carbon pollution by nearly a quarter in February. India and Europe cut emissions by 26% and 27%, respectively.

The biggest global drop since the start of the COVID-19 pandemic occurred between April 4 and 9. During that period, the world spewed 18.7 million fewer tons of carbon pollution per day than it did on New Year’s Day.

Such low global emission levels haven’t been recorded since 2006. But if the world returns to its slowly increasing pollution levels next year, the temporary reduction amounts to “a drop in the ocean,” said study lead author Corinne LeQuere, a climate scientist at the University of East Anglia.

“It’s like you have a bath filled with water and you’re turning off the tap for 10 seconds,” she said.

By April 30, the world carbon pollution levels had grown by 3.3 million tons a day from its low point earlier in the month.

Carbon dioxide stays in the air for about a century.

Independent scientists praised the study as the most comprehensive yet, saying it shows how much effort is needed to prevent dangerous levels of further global warming.

“That underscores a simple truth: Individual behavior alone ... won’t get us there,” Pennsylvania State University climate scientist Michael Mann, who wasn’t part of the study, said in an email. “We need fundamental structural change.”

If the world could keep up annual emission cuts like this without a pandemic for a couple decades, there’s a decent chance Earth can avoid an additional 1.8 degrees of warming from now, study authors said. But getting the type of yearly cuts to reach that international goal is unlikely, they said.

If next year returns to 2019 pollution levels, it means the world has only bought about a year’s delay in hitting the extra 1.8 degrees of warming that leaders are trying to avoid, LeQuere said. That level could still occur anytime from 2050 to 2070, the authors said.

The study was carried out by Global Carbon Project, a consortium of international scientists that produces the authoritative annual estimate of carbon dioxide emissions. They looked at 450 databases showing daily energy use and introduced a measurement scale for pandemic-related societal “confinement” in its estimates.

Nearly half the emission reductions came from less transportation pollution, mostly involving cars and trucks, the authors said. By contrast, the study found that drastic reductions in air travel accounted for only 10% of the overall pollution drop.

In the U.S., the biggest pollution declines were seen in California and Washington, where emissions plunged more than 40%.