The global lockdown inspired by the novel coronavirus, COVID-19, has shuttered factories and reduced travel, slashing lethal pollution including the greenhouse gases that are heating the climate.

The lockdown may save more lives from pollution reduction than are threatened by the virus itself, said François Gemenne, director of The Hugo Observatory, which studies the interactions between environmental changes, human migration, and politics, according to an article by Forbes.

“Strangely enough, I think the death toll of the coronavirus at the end of the day might be positive, if you consider the deaths from atmospheric pollution,” said Gemenne, citing, for example, the 48,000 people who die annually in France because of atmospheric pollution and the more than one million in China.

Scientists estimate the U.S. death toll from air pollution at more than 100,000 per year, and the World Health Organization estimates the global toll at 7 million.

The global death toll of an uncontained pandemic remains largely a matter of conjecture. The most dramatic projections that have been released—too hastily to be peer reviewed—put the global death toll of an unchecked pandemic in the millions—total, not annual. Most credible estimates are much less. Some experts have compared it to the 1957 flu outbreak that killed just over 1 million. The toll from a contained outbreak would of course be much smaller.

Reductions in air pollution and global heating could save more lives.

“More than likely the number of lives that would be spared because of these confinement measures would be higher than the number of lives that would be lost because of the pandemic,” Gemenne said in an appearance on France 24’s The Debate.