But climate experts stressed that global CO2 emissions must turn around and shrink on a sustained basis if climate targets are to be met. The IEA said that “emissions still remain on an unsustainable growth trajectory.”

“The apparent slowdown in carbon emissions last year is no cause for celebration,” said Antoine Halff, a founding partner of Kayrros, an energy consulting firm that makes extensive use of satellite images. “This is not a positive achievement flowing from virtuous climate policies, but rather a byproduct of Russian aggression and its adverse effect on European energy-intensive industries on the one hand, and on the other hand the nefarious effect of China’s public health policies on its economy.”

The carbon dioxide growth rate was much slower than 2021’s blistering pace of more than 6 percent. That figure had been fueled by a rebound from pandemic-related weakness in energy use, the agency said.

Last year had its own litany of disruptions. It was marked by war in Ukraine, disruptions in Russian oil and gas exports, pandemic-related work restrictions in China, international energy price shocks, rising inflation, and disruptions in trade flows.

As a result, the IEA said that the increase was not as fast as the agency feared. Industrial production in China and Europe was curtailed. Natural gas consumption in Europe plunged 13.5 percent. And renewables met 90 percent of last year’s global growth in electricity generation, the IEA said.

“Two major events contributed to reducing emissions last year,” said Halff. “China’s zero covid policy and the war in Ukraine took a big bite off of world carbon emissions last year, but that was partly offset by a resurgence of coal as a substitute for scarce or pricey natural gas.”

Of the 321-million-metric-ton increase in carbon dioxide emissions, just over half could be attributed to cooling and heating demand in extreme weather and the rest to nuclear power plants being offline.

U.S. emissions grew by 0.8 percent, with extreme temperatures forcing the building sector to provide the highest emissions growth. The main cutbacks in emissions came from unprecedented increases in solar and wind output. While many other countries, such as Germany, reduced their natural gas use, the United States increased its use by 89 million metric tons.

Coal is another factor in rising emissions. Before the pandemic, coal seemed to be on its last legs — which was part of why many scientists in 2020 thought emissions might have reached their peak. But in the past couple of years, coal has made a resurgence. The war in Ukraine has raised natural gas prices around the world, causing some European countries to lean more heavily on coal to keep energy prices low.

Going forward, this fossil fuel may have more of a future than analysts previously thought. China last year approved the largest expansion of coal-fired power plants since 2015, according to a new report by the Center for Research on Energy and Clean Air (CREA), a Finland-based nongovernmental organization, and the Global Energy Monitor, a nonprofit that tracks fossil fuel infrastructure.

The expansion of coal plants runs counter to Chinese President Xi Jinping’s 2020 pledge that the country’s carbon dioxide emissions would peak before 2030. Xi has also said that the country will begin to “phase down” coal consumption from 2026 onward, but he has not said when new projects will stop.