Rising rocket launches linked to ozone layer thinning
by Sandro Vattioni and Timofei Sukhodolov, ETH Zurich
The United Nations and Climate Standards
Rising global rocket launches could have damaging effects on the ozone layer, which protects the Earth from harmful ultraviolet radiation. Research suggests that emissions from rocket launches are a growing environmental concern, yet they remain largely unregulated.
Pollutants from Rocket Launches
Rocket launches and the emissions from re-entering spacecraft introduce pollutants that can have damaging effects on the ozone layer, particularly chlorine and soot, which can greatly exacerbate ozone depletion over time.
Moreover, recent data indicate that as the global rate of rocket launches rises—from only 97 launches in 2019 to a projection of 258 launches in 2024—there's an accompanying acceleration in atmospheric depletion. Each rocket emits various chemical compounds including nitrogen oxides that can catalyze ozone depletion.
Research Methods and Findings
Research undertaken by a team led by Laura Revell from the University of Canterbury used a chemistry climate model to project the future impacts of increased rocket launches. By simulating emissions patterns and atmospheric chemistry, the study forecasted that by 2030 the ozone layer could see a decline in its thickness of about 0.3%, with significant drops of up to 4% over Antarctica, where recovery is already at a slower rate due to previous damages from chlorofluorocarbons (CFCs).
Chlorofluorocarbons and Current Challenges
The depletion of the ozone layer due to CFCs—successfully addressed by global treaties—serves as a reminder of how international cohesiveness can mitigate environmental threats. However, without proactive policies regulating rocket emissions, the recovery trajectory for the ozone layer is at risk of projection delays stretching into decades.
Assessment of Rocket Fuel Types
| Type of Fuel | Chlorine Emissions | Soot Emissions |
|---|---|---|
| Solid Rocket Fuels | High | High |
| Liquid Cryogenic Fuels | Low | Low |
To mitigate emissions and their effect on the ozone layer, only a small percentage of launches currently utilize relatively safe cryogenic fuels due to their complex handling requirements. This method, while effective, is not widely adopted in the industry.
The Bigger Picture
The ongoing increase in satellite re-entries raises additional concerns. As satellites return to Earth, they burn up upon re-entry, generating pollutants, including nitrogen oxides—potent catalysts for ozone depletion. Moreover, the metals released during these processes could serve as surface catalysts for further ozone-depleting reactions, compounding risks.
