Rockets May Eat Away on the Ozone Layer

Rocket emissions and re-entry pollution threaten to delay ozone restoration, however coordinated motion and cleaner propulsion might forestall long-term injury.

The sharp improve in international rocket launches might hinder the restoration of the ozone layer, warns Sandro Vattioni. Although the danger is being underestimated, he notes that it could possibly be diminished by way of proactive and coordinated measures.

In current years, the enlargement of satellite tv for pc constellations in low Earth orbit has remodeled the evening sky, fueled by the fast progress of the house trade. This progress creates main alternatives but in addition raises environmental challenges. Pollutants launched throughout rocket launches and from burning particles throughout re-entry accumulate within the center environment, the place they’ll injury the ozone layer — Earth’s protect towards dangerous ultraviolet radiation. Scientists are solely starting to completely assess the size of this menace.

Investigations into how rocket emissions have an effect on ozone started greater than three many years in the past, however for a few years the impression was thought of minimal. As the frequency of launches continues to rise, this view is shifting. In 2019, solely 97 orbital launches have been recorded worldwide, however by 2024 the determine had climbed to 258, with projections pointing to continued fast progress.

An extended-underestimated concern

Unlike ground-level pollution, emissions from rockets and re-entering satellites can persist within the center and higher environment as much as 100 instances longer, since removing processes similar to precipitation don’t happen at these altitudes. While most launches happen within the Northern Hemisphere, atmospheric circulation finally distributes the pollution globally.

To examine long-term results, researchers from ETH Zurich and the Physical Meteorological Observatory in Davos (PMOD/WRC), in collaboration with Laura Revell’s worldwide staff on the University of Canterbury, used a chemistry–local weather mannequin to simulate how future emissions would possibly impression the ozone layer by 2030.

In a high-growth state of affairs with 2,040 annual launches by 2030 — roughly eight instances the 2024 complete — the mannequin predicts that international common ozone thickness would lower by almost 0.3%. Seasonal losses might attain as a lot as 4% over Antarctica, the place the ozone gap continues to reappear every spring.

While these reductions might seem small, the context is essential. The ozone layer continues to be recovering from earlier depletion brought on by long-lived chlorofluorocarbons (CFCs), which have been banned below the 1989 Montreal Protocol. Even immediately, international ozone thickness stays about 2% under pre-industrial ranges, and full restoration is just not anticipated till round 2066. The examine means that unchecked rocket emissions — which at the moment stay unregulated — might push this timeline again by a number of years and even many years, relying on how shortly the house trade expands.

With rockets, too, the selection of gas issues

The major contributors to ozone depletion from rocket emissions are gaseous chlorine and soot particles. Chlorine catalytically destroys ozone molecules, whereas soot particles heat the center environment, accelerating ozone-depleting chemical reactions.

While most rocket propellants emit soot, chlorine emissions primarily come from stable rocket motors. Currently, the one propulsion methods which have a negligible impact on the ozone layer are these which use cryogenic fuels similar to liquid oxygen and hydrogen. However, as a result of technological complexity of dealing with cryogenic fuels, solely about 6% of rocket launches at the moment use this know-how.

Re-entry results are nonetheless unsure

We wish to point out that our examine solely thought of emissions launched from rockets throughout ascent into house. But that is solely a part of the image. Most satellites in low Earth orbit re-enter the environment on the finish of their operational life, burning up within the course of.

This course of generates further pollution, together with numerous steel particles and nitrogen oxides, as a result of intense warmth generated upon re-entry. While nitrogen oxides are identified to deplete ozone catalytically, steel particles might contribute to forming polar stratospheric clouds or function response surfaces themselves, each of which might intensify ozone loss.

These re-entry results are nonetheless poorly understood and never but included into most atmospheric fashions. From our perspective, it’s clear that with rising satellite tv for pc constellations, re-entry emissions will turn into extra frequent, and the whole impression on the ozone layer is more likely to be even larger than present estimates. Science is known as upon to fill these gaps in our understanding.

Needed: Foresight and coordinated motion

But that alone won’t be sufficient. The excellent news: We consider a launch trade that avoids ozone-damaging results is fully potential: Monitoring rocket emissions, minimizing the utilization of chlorine and soot-producing fuels, selling different propulsion methods, and implementing the mandatory and acceptable rules are all key to making sure that the ozone layer continues its restoration. This will take coordinated efforts between scientists, policymakers, and trade.

The Montreal Protocol efficiently demonstrated that even planetary-scale environmental threats could be addressed by way of international cooperation. As we enter a brand new period of house exercise, the identical type of foresight and worldwide coordination might be wanted to keep away from dangerous results on the ozone layer – one of many Earth’s most significant pure shields.

Reference: “Near-future rocket launches could slow ozone recovery” by Laura E. Revell, Michele T. Bannister, Tyler F. M. Brown, Timofei Sukhodolov, Sandro Vattioni, John Dykema, David J. Frame, John Cater, Gabriel Chiodo and Eugene Rozanov, 9 June 2025, npj Climate and Atmospheric Science.
DOI: 10.1038/s41612-025-01098-6

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