Cargo Planes Could Cool Overheating Planet

Existing aircraft could be used to cool Earth by spraying particles high above the polar regions, according to groundbreaking research that suggests planetary cooling technology may be more accessible than previously thought.

Scientists at University College London discovered that regular cargo planes like the Boeing 777F could potentially deliver particles to reflect sunlight back into space, potentially lowering global temperatures without the need for specialized high-altitude aircraft.

“Solar geoengineering comes with serious risks and much more research is needed to understand its impacts. However, our study suggests that it is easier to cool the planet with this particular intervention than we thought,” said Alistair Duffey, lead author and PhD student at UCL’s Department of Earth Sciences.

The technique, known as stratospheric aerosol injection, works by releasing sulfur dioxide particles into the upper atmosphere, where they reflect incoming sunlight before it can warm the planet. While most previous research assumed these particles would need to be deployed around 20km above the equator, the new study shows meaningful cooling effects could be achieved at just 13km above the poles.

This matters because commercial aircraft can reach 13km, while specially designed planes capable of reaching 20km might require billions of dollars and a decade of development time. The discovery potentially moves geoengineering from theoretical concept toward something that could be implemented more quickly if climate change accelerates dangerously.

Using sophisticated climate simulations, researchers calculated that injecting 12 million tonnes of sulfur dioxide annually—approximately the same amount released by the 1991 Mount Pinatubo volcanic eruption—could cool the planet by around 0.6°C.

This approach does come with significant drawbacks, however. The study found that particles released at lower altitudes don’t stay in the atmosphere as long, meaning the cooling effect is about three times less efficient than high-altitude deployment near the equator.

“At this lower altitude, stratospheric aerosol injection is about one third as effective. That means that we would need to use three times the amount of aerosol to have the same effect on global temperature, increasing side effects such as acid rain,” Duffey explained.

Another limitation is that this polar approach would provide less cooling in tropical regions, where climate vulnerability is often highest. Despite these challenges, researchers believe understanding all possible climate intervention options is crucial given the growing threats posed by warming.

The sulfur dioxide would need to be released around 60 degrees north and south of the equator—approximately the latitude of Oslo, Norway and Anchorage, Alaska, and just south of the tip of South America in the southern hemisphere.

Wake Smith, a Yale School of the Environment lecturer and co-author of the study, noted that while existing aircraft would still require modifications to function as deployment tankers, “this route would be much quicker than designing a novel high-flying aircraft.”

Researchers emphasized that any implementation would require a gradual approach, as sudden changes in cooling or warming could have catastrophic consequences. They also stressed that geoengineering remains a supplement to—not a replacement for—reducing greenhouse gas emissions.

“Stratospheric aerosol injection is certainly not a replacement for greenhouse gas emission reductions as any potential negative side effects increase with the amount of cooling: we can only achieve long-term climate stability with net zero,” said Dr. Matthew Henry from the University of Exeter, who co-authored the study.

As global temperatures continue to rise and climate tipping points loom closer, this research provides policymakers with crucial information about potential emergency measures that could buy time while the world transitions away from fossil fuels.