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Perhaps nothing signals the arrival of summer in the United States like the familiar soft whir of air-conditioning. But there is growing concern that as other countries adopt America’s love of air conditioners, the electricity used to power them will overburden electrical grids and increase planet-warming emissions.

The number of air conditioners worldwide is predicted to soar from 1.6 billion units today to 5.6 billion units by midcentury, according to a report issued Tuesday by the International Energy Agency. If left unchecked, by 2050, air conditioners would use as much electricity as China does for all activities today.

Greenhouse gas emissions released by coal and natural gas plants when generating electricity to power those air conditioners would nearly double, from 1.25 billion tons in 2016 to 2.28 billion tons in 2050, the report says. Those emissions would contribute to global warming, which could further heighten the demand for air-conditioning.

While 90 percent of U.S. households have air-conditioning, “When we look in fact at the hot countries in the world, in Africa, Asia, Latin America and the Middle East, where about 2.8 billion people live, only about 8 percent of the population owns an air conditioner,” said Fatih Birol, executive director of the energy agency.

As incomes in those countries rise, however, more people are installing air conditioners in their homes. The energy agency predicted much of the growth in air-conditioning will occur in India, China and Indonesia.

When it gets hot, forgoing air-conditioning can be deadly. That is why Birol said the solution lies not in convincing countries to forgo air conditioners, but in making air-conditioning more energy efficient. Many air conditioners on sale in India today use twice as much electricity to provide the same amount of cooling as more efficient units, said Lucas Davis, director of the Energy Institute at the Haas School of Business of the University of California, Berkeley.

No matter what, air-conditioning will be a major issue in the fight against climate change, Birol said.

“When I look at the next few years to come, air conditioners are only second to the entire industrial sector,” he said.