Rising rocket launches linked to ozone layer thinning

The rapid increase in global rocket launches could slow down the recovery of the vital ozone layer, explains Sandro Vattioni. The problem is underestimated – but it could be attenuated by a prospective coordinated action.

In recent years, the night sky has filled with satellites from expansion constellations in low terrestrial orbit, driven by a booming space industry. Although this development brings exciting opportunities, it also raises new environmental concerns.

The rocket launches and reintegrating space debris release pollutants into the central atmosphere, where they can damage the ozone layer that protects life on earth against the influence of harmful UV – an increasing concern that scientists only understand.

Research on the effects of rocket emissions on the ozone layer started over 30 years ago, but for a long time, these effects were considered small. This perception begins to change as the launch activity accelerates. In 2019, there were only 97 launches of orbital space rockets worldwide. By 2024, this number had increased to 258 and should continue to increase quickly.

A long-term concern for a long time

In the medium and upper atmosphere, rocket emissions and spatial debris that come in can remain up to 100 times longer than emissions from ground sources due to the absence of elimination process such as cloud -based washing. While most launches occur in the northern hemisphere, atmospheric circulation spreads these pollutants worldwide.

To better understand the long -term impact of the increase in rocket emissions, we have collaborated with an international research team led by Laura Revell from the University of Canterbury. Using a climate model of chemistry developed in Eth Zurich and the physical meteorological observatory in Davos (Pmod / WRC), we have simulated how projected rocket emissions will affect the ozone layer by 2030. The study is published in the journal NPJ climate and atmospheric science.

Assuming a growth scenario with 2,040 annual launches in 2030, or eight times the figure for 2024 – the average thickness of overall ozone would decrease by almost 0.3%, with seasonal discounts up to 4% compared to Antarctica, where the ozone hole is still formed each spring.

Although these figures may seem modest at first glance, it is important to remember that the ozone layer is still recovering from previous damage caused by long -term chlorofluorocarbons (CFC), which have been successfully prohibited by the Montreal protocol in 1989. The emissions of the rockets – accidentally unregulated – could delay this recovery by years or years decades, according to the growth of the rocket industry.

With rockets too, the choice of fuel counts

The main contributors to the exhaustion of ozone rocket emissions are gaseous chlorine and soot particles. Chlorine catalystly destroys ozone molecules, while soot particles warm the average atmosphere, accelerating chemical reactions impoverishing ozone.

While most of the rocket propellants emit soot, chlorine emissions come mainly from solid rocket engines. Currently, the only propulsion systems that have a negligible effect on the ozone layer are those that use cryogenic fuels such as liquid oxygen and hydrogen. However, due to the technological complexity of the handling of cryogenic fuel, only about 6% of rocket launches are currently using this technology.

Back to school effects are still uncertain

We would like to mention that our study considered only the releases released from the rockets during the ascent in space. But this is only part of the image. Most satellites in low terrestrial orbit enter the atmosphere at the end of their operational life, burning in the process.

This process generates additional pollutants, including various metallic particles and nitrogen oxides, due to the intense heat generated during the start of the school year. Although nitrogen oxides are known to exhaust catalystly ozone, metallic particles can help form polar stratospheric clouds or serve as reaction surfaces themselves, which can both intensify the loss of ozone.

These return to school effects are still poorly understood and not yet incorporated into most atmospheric models. From our point of view, it is clear that with the increase in the constellations of satellites, the start -up emissions will become more frequent and the total impact on the ozone layer is probably even higher than current estimates. Science is called upon to fill these shortcomings in our understanding.

Necessary: Provident and coordinated action

But that alone will not be enough. The good news: we believe that a launching industry avoids the damaging effects of ozone is quite possible: monitoring rocket emissions, minimizing the use of chlorine and fuels producing soot, promoting alternative propulsion systems, and the implementation of the necessary and appropriate regulations is all key to guarantee that the ozone layer continued its recovery.⁴ This will take coordinated efforts between scientists, decision -makers and industry.

The Montreal Protocol has successfully demonstrated that even environmental threats on a planetary scale can be treated by global cooperation. While we are entering a new era of spatial activity, the same type of foresight and international coordination will be necessary to avoid the harmful effects on the ozone layer – one of the most vital natural shields of the earth.