That rapidly increasing number of space launches may pose a new threat to Earth’s critical ozone layer, according to a growing body of scientific research.
Our ozone layer is often touted as a global environmental success story. Since the signing of the Montreal Protocol in 1987 – an international treaty to protect the ozone – countries around the world have come together to stop producing and emitting the chemical compounds that contributed to the dramatic thinning of the ozone layer over Antarctica. Despite a brief setback in the 2010s, the latest UN report released in January shows that we on the way to full ozone recovery by 2066.
Yet the UN’s assessment also included a caveat: Just because we’re on the road to ozone recovery doesn’t mean it’s a guarantee. Several dangers, old and new, could emerge to derail decades of global progress. Among these potential dangers to ozone are geoengineering proposal which aims to mitigate climate change. There is also the threat of climate change itself; more aerosol and greenhouse gas emissions can damage ozone recovery. And as the UN points out, space launches are another thing for us to consider.
“Rocket launches currently have little effect on total stratospheric ozone,” the researchers write in their report. But that is likely to shift going forward with new propellants, satellite constellations and the continued increase in the number of space launches, the report notes. More than 180 rockets was launched into space in 2022 – the largest ever in a single year – while the number of satellites launched has increased exponentially, according to a review study published last month in the Journal of the Royal Society of New Zealand.
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“We’ve known since the early ’90s that rocket launch emissions could lead to ozone depletion. But it’s never really been a big problem before because we’ve had so few launches that the effects are negligible,” said Laura Revellan atmospheric chemist at the University of Canterbury in New Zealand and senior author of this study, in a video call with Gizmodo.
But that is beginning to change, which means research, monitoring and exploration of space must change as well, Revell noted. Impact of rocket launches on the upper atmosphere goes widely unmonitored and unregulated, she said. “But we think this is the right time to act — before the number of launches worldwide really scales up.”
Revell’s recent review, conducted with two other researchers, assessed the increasing threat posed by space launches. Across dozens of previous studies the researchers looked at, they found evidence that several emission products from launches can negatively affect ozone through various chemical reactions or the temperature shifts they cause. These emissions of concern include water vapor, nitrogen oxides, black carbon, aluminum oxide particles, hydrogen gas and hydrogen chloride. Furthermore, the launch mechanism means that these ozone-depleting gases and particles are delivered directly to the place where they can do the most damage: the stratosphere, where 90% of atmospheric ozone is found.
Although some researchers have begun to look at the effects of individual launches in the real world, it remains an understudied area, where the science is based more on models than true observations. There are many things we still don’t know, Revell stressed. “Measurements of exhaust plumes are limited, and most current data rely heavily on plume modeling or best estimates from combustion calculations. Even the most ubiquitous fuel, liquid petroleum, remains relatively poorly modeled in exhaust concentrations,” the study authors wrote.
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As researchers assess the details of individual launches, they will islandoften find disturbing results. ONE 2022 survey that modelsd 2016 Falcon 9 launch of the Thaicom-6 satellite found that this single launch probably produced a ton of ozone-depleting nitrogen oxides— corresponding to the annual emissions of around 1,400 cars. Furthermore, the amount of total ozone loss from rocket launches may be more than 10 times what has previously been assumed due to a lack of comprehensive research, according to 2022 modelin the studio.
For context: Most living things on Earth depend on an intact ozone layer to survive and thrive. The protective blanket of atmospheric ozone absorbs the sun’s most harmful rays, known as UVB light wavelengths, which cause skin cancer, cataracts and crop damage. among other. ONE healthy ozone also protects us from an even worse version of climate change. Without it, the world would be 4.5 degrees Fahrenheit warmer than it is now.
But just because rocket launches are increasing doesn’t mean the ozone layer has to decrease. In addition to identifying the problem of increasing space launches and potential ozone damage, Revell and her co-authors also suggested a way forward for atmospheric scientists and private space companies to tackle the problem. In their view, a sustainable future for spaceflight is within reach, and the sooner we make changes, the better.
Some of their proposed changes include more research and monitoring to keep track of launch emissions and greater access to open data on launch emissions. Another recommendation is for launch providers to consider the stratospheric effects of their rockets at the design and testing stage.
“This is not a prediction of doom and gloom,” said Tyler Brown, an astrophysicist at the University of Canterbury and first author on the review study, in an email to Gizmodo.”Many things can and will change in the future. Our main goal is to get people discussing a sustainable rocket industry in the present with a serious lens for action – not just awareness.”
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