Carbon dioxide emissions have fallen dramatically since lockdowns were imposed around the world due to the coronavirus crisis, research has shown.

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,” said study leader Corinne Le Quéré, of the University of East Anglia in Norwich, England.

Worldwide, daily emissions fell by 17% — or 17 million metric tons of carbon dioxide — during the peak of the pandemic confinement measures in early April, compared to average daily levels in 2019, the researchers found.

When the lockdown was at its most stringent, in some countries emissions fell by just over a quarter (26%) on average.

The last time that daily carbon dioxide emissions were this low was in 2006.

The study centered on 69 countries, all 50 US states and 30 Chinese provinces, which account for 85% of the world population and 97% of all global carbon dioxide emissions.

Emissions from cars and other types of “surface transport” accounted for almost half of the decrease in global emissions during peak confinement on April 7, while emissions from industry and power plants together accounted for 43% of the decrease, the study found.

“This is a really big fall, but at the same time, 83% of global emissions are left, which shows how difficult it is to reduce emissions with changes in behaviour,” said Corinne Le Quéré.

The unprecedented fall is likely to be only temporary. As countries slowly get back to normal activity, over the course of the year the annual decline is likely to be only about 7%, if some restrictions to halt the virus remain in place. However, if they are lifted in mid-June the fall for the year is likely to be only 4%.