Scientists want to regulate space tourism: It damages the ozone layer and emits black soot into the atmosphere

Blue Origin is one of the companies offering space tourism services. Illustration: Blue Origin

The world’s super-rich’s stroll in space for pleasure comes with a cost for the climate.

The rockets are a threat to the ozone layer recovery, which has been going on since the late 1980s, and they also emit soot particles, which contribute to global warming.

This is the conclusion of a study carried out by researchers from University College London, the University of Cambridge, and the Massachusetts Institute of Technology, published in the Earth’s Future journal.

“This study allows us to enter the new era of space tourism with our eyes wide open to the potential impacts. The conversation about regulating the environmental impact of the space launch industry needs to start now so we can minimize harm to the stratospheric ozone layer and climate,” says Dr. Robert Ryan in a press release from University College London.

Together with his colleagues, he has developed a 3D model that can be used to explore the impact of 103 rocket launches that took place in 2019. The model can also be used to estimate the impact of the industry in the future based on various scenarios.

Montreal Protocol in danger

The ozone layer is found in Earth’s atmosphere and is important because it protects the planet from the Sun’s ultraviolet radiation, which can harm humans, plants, and animals. However, human emissions of ozone depleting substances have led to a partial degradation of the layer.

In order to protect the ozone layer, countries around the world signed the so-called Montreal Protocol in 1987. They undertook to phase out the use of substances that could damage the ozone layer.

It is the positive effects of this treaty that scientists fear space tourism could jeopardize. This is because solid fuels from rockets have a very harmful effect on the ozone layer. At the same time, the heat from returning spacecraft is also depleting the ozone layer.

“The only part of the atmosphere showing strong ozone recovery post-Montreal Protocol is the upper stratosphere, and that is exactly where the impact of rocket emissions will hit hardest. We weren't expecting to see ozone changes of this magnitude, threatening the progress of ozone recovery,” Dr. Robert Ryan says.

At present, however, the effect on the ozone layer is small, but the researchers point out that it will increase as space tourism becomes more common.

Black soot contributes to global warming

The researchers are also concerned about the industry’s contribution to global warming. The rockets emit black soot particles, which, much like CO2, contribute to the greenhouse effect.

Admittedly, the soot particles do not stay in the atmosphere for as long as CO2 and other greenhouse gases, but because the soot is directly injected into the upper atmosphere, the researchers expect that the effect will be approximately 500 times greater than from the soot particles emitted from the ground.

And the problem seems to be growing. Over the last 3 years, the total global warming effect caused by rocket pollution has more than doubled.

“Soot particles from rocket launches have a much larger climate effect than aircraft and other Earth-bound sources, so there doesn’t need to be as many rocket launches as international flights to have a similar impact. What we really need now is a discussion amongst experts on the best strategy for regulating this rapidly growing industry,” says Dr. Eloise Marais, one of the researchers behind the study.