As billionaires race to space, they could harm the climate back here on Earth.

Eloise Marais is an associate professor at University College London and co-author of a recent study on the climate impact of rocket launches.

She says that some rockets use carbon-based fuels that produce heat-trapping greenhouse gases when burned.

“There are also other kinds of byproducts that contribute to climate change,” she says. “Water vapor is produced by some of the rockets, and that is a strong greenhouse gas as well. But there are also other pollutants that aren’t necessarily classified as greenhouse gases, like black carbon or soot. And those can have a warming effect as well.”

The effect is particularly strong when rockets release the pollution directly into the upper atmosphere.

“As they are launched, they release pollutants all the way from the surface of the Earth to their destination,” Marais says. “And these pollutants can last in the upper atmosphere for longer than they last at the surface of the Earth. And so they can persist for two, three years, maybe more.”

So although the number of rocket launches is still small, Marais says it’s important to consider the risks of a growing space tourism industry.

Reporting credit: ChavoBart Digital Media and Samantha Harrington