Recent research highlights a novel approach to climate intervention through Stratospheric Aerosol Injection (SAI), which could utilize existing aircraft to cool the Earth. University College London (UCL) researchers have just released an important new study of climate intervention. The researchers realized that by deploying particles such as sulfur dioxide into the stratosphere they could form far-reaching cooling influences, especially around the polar regions. This approach seeks to remove CO 2 from the atmosphere to counteract increasing worldwide temperatures while introducing important questions about its viability and potential environmental effects.
The plan involves shooting sulfur dioxide particles into the stratosphere roughly 13 kilometers above Earth’s surface. This would greatly benefit the polar regions, especially during their local spring and summer months. While this could potentially cool the planet by around 0.6°C, it is considerably less effective than injections made at higher altitudes closer to the equator. The research, simulated using the UK’s Earth System Model 1 (UKESM1), underscores the viability of SAI as a temporary climate control measure, albeit with associated risks and limitations.
Mechanism of Stratospheric Aerosol Injection
Specifically, Stratospheric Aerosol Injection would involve injecting massive amounts of reflective particles into the stratosphere, a stable, dry layer of the atmosphere. This unique environment allows particles to be stored long-term, even for up to multiple years at higher altitudes. At 13 kilometers, the particles don’t stay in the air for more than a few months, making them much less effective. This research makes clear that if we ever trigger SAI, its cooling power could be substantial. This effect is most pronounced when it’s introduced at 60 degrees north and south of the equator.
According to current projections, injecting 12 million metric tons of sulfur dioxide annually at this altitude could recreate the overall impacts of the 1991 eruption of Mount Pinatubo. The aftermath of that eruption, which included sharp decline in global temperatures. Researchers warn that to reproduce this effect with SAI would take three times that amount of aerosol at lower altitudes. This greatly increases the chances of negative side effects, not the least of which is acid rain.
“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.” – Dr. Matthew Henry
Feasibility and Future Implications
There are many hurdles for implementing Stratospheric Aerosol Injection in practice. Designing and certifying high-flying aircraft for those injections will require a decade at least. Funding this ambitious project would come with a multimillion-dollar price tag. You would re-purpose airframes that are already in service to do so. They would need some serious changes to operate as effective deployment tankers.
“Although pre-existing aircraft would still require a substantial modification program to be able to function as deployment tankers, this route would be much quicker than designing a novel high-flying aircraft.” – Wake Smith
Alistair Duffey, a Ph.D. student at UCL’s Department of Earth Sciences, is the study’s first author. It’s important to focus on these coolers. He insists that, though solar geoengineering is full of risks, it has made quicker, cooler options available to us than we ever imagined.
“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. This has implications for how quickly stratospheric aerosol injection could be started and by who.” – Alistair Duffey
Risks and Ethical Considerations
Like any other geoengineering strategy, Stratospheric Aerosol Injection poses ethical dilemmas and environmental consequences that should be thoughtfully addressed. The risk of unintended consequences is high, especially when it comes to these impacts on localized weather patterns and ecosystems. Critics believe a focus on these types of techniques would create a disincentive to pursue more environmentally necessary initiatives to cut greenhouse gas emissions.
In addition to revealing long-standing gaps in the literature, the study reinforces the need for more research into SAI’s long-term impacts on global climate systems. Understanding how this intervention might interact with ongoing climate change is crucial in determining its viability as a supplementary strategy alongside traditional mitigation efforts.