The Coronavirus and Carbon Emissions

In the past month, the world has seen a remarkably large drop in emissions of carbon dioxide, the main driver of global warming. The reason isn’t something to celebrate, though.

The coronavirus outbreak in China, which has sickened at least 77,000 people, has shut down factories, refineries and flights across the country as officials order people to stay home. As a result, China’s carbon dioxide emissions over the past three weeks have been about 25 percent lower than during the same period last year, according to calculations by Lauri Myllyvirta, an analyst at the Center for Research on Energy and Clean Air.

China is such a huge industrial polluter that even a temporary dip like this is significant: The three-week decline is roughly equal to the amount of carbon dioxide that the state of New York puts out in a full year (about 150 million metric tons) Mr. Myllyvirta estimated.

Every year, the nation’s coal use falls during the weeklong holiday around the Lunar New Year, which occurred on Jan. 25 this year. Coal-burning emissions then typically rise again once people return to work and factories spring back to life. But this year, coal use has yet to rebound. In late January, the Chinese authorities extended the New Year’s holiday and restricted travel and public gatherings in an attempt to stop the coronavirus from spreading.

The effects have rippled through virtually all sectors of China’s economy.