The space tourism industry could have a greater effect on the climate than the aviation industry if left unregulated, a new study published in the journal “Earth’s Future” has shown. According to the study, black carbon particles (soot) emitted by rockets are nearly 500 times more efficient at storing heat in the atmosphere than all other sources of soot combined (surface and aircraft).
In 2019, researchers from UCL, the University of Cambridge and MIT used a 3D model to explore the impact of rocket launches and re-entries. They also analyzed the impact of projected space tourism scenarios based on the recent multi-billion dollar space race. This resulted in a greater effect on climate.
While the study revealed that the current total ozone loss due to rockets is small, current growth trends around space tourism indicate that it could be damaged in the Arctic during the spring. This is because pollutants from solid-fuel rockets, spacecraft re-entry heating and debris are particularly damaging to stratospheric ozone.
Soot particles from rocket launches have a much larger climate effect than aircraft and other ground-based sources.
Eloise Marais, co-author of the study
“Rocket launches are routinely compared to emissions of greenhouse gases and air pollutants from the airline industry, which we show in our work to be wrong,” said co-author Eloise Marais, from the UCL’s Department of Geography. ”Soot particles from rocket launches have a much larger climate effect than aircraft and other ground-based sources. There doesn’t need to be as many rocket launches as international flights to have a similar impact.
The researchers collected information on chemicals from the 103 rocket launches in 2019 around the world, as well as data on reusable rocket reentry and space debris.
They also used recent Virgin Galactic, Blue Origin and SpaceX test flights, as well as Virgin Galactic’s proposed annual, at least daily, launches to build a scenario of a future formidable space tourism industry. This data was then incorporated into a 3D model to explore the impact on climate and the ozone layer.
The team suggests that warming due to soot more than doubles after just three years of additional emissions from space tourism launches. According to the researchers, this is of particular concern because when soot particles are injected directly into the upper atmosphere they have a much greater effect on climate than other sources of soot, since the particles are 500 times more efficient at retaining heat.
What we really need now is a discussion among experts about the best strategy for regulating this rapidly growing industry.
Eloise Marais, co-author of the study
Under a scenario of daily or weekly space tourism rocket launches, the impact on the stratospheric ozone layer threatens to undermine the recovery that has taken place following the successful implementation of the Montreal Protocol, the study suggests.
Lead author of the study, Robert Ryan of UCL’s Department of Geography, said, “The only part of the atmosphere that shows strong ozone recovery after the Montreal Protocol is the upper stratosphere, and that is exactly where the impact of rocket emissions will be much greater.”
The study has allowed scientists to enter the new era of space tourism with a better understanding of the potential impact. According to the authors of the study, the conversation about regulating the environmental impact of the space launch industry must begin now so that damage to the stratospheric ozone layer can be minimized.”
“We did not expect to see ozone changes of this magnitude, that could threaten the progress of ozone recovery,” said Robert Ryan. “There is still much we need to find out about the influence of rocket launch and atmospheric reentry emissions, in particular, the future size of the industry and the types and byproducts of new fuels such as liquid methane and derived biofuels.”
