Tales of heatwaves and natural disasters have taken our lives and our media by storm in the past few years. As humanity inches closer than ever before to crossing irreversible tipping points, we must consider the question of whether or not greenhouse gas emission reduction alone can stop the climate crisis. One possible solution to reversing climate change may lie in solar geoengineering — a technology that could postpone climate tipping points, but may also have the potential to create a new climate catastrophe.
The premise of geoengineering is that as humans understand how the Earth works, we can engineer it back to its condition prior to anthropogenic climate change. Solar geoengineering, also known as solar radiation management, works to cool the Earth by reflecting sunlight back into space. Yet this technology does not address greenhouse gas emissions, the root cause of climate change, and has the potential for serious harm: solar geoengineering could interfere with our weather patterns, cause acid rain, deplete the ozone layer, and cause more unknown side effects. The higher Earth’s temperatures rise, the more likely humanity will become desperate to cool off and employ strategies including solar geoengineering — regardless of the consequences. Solar geoengineering research needs to be done now so that if it becomes necessary, humanity will be prepared for all possible outcomes.
The scale of solar geoengineering requires that global policymakers and the public be in agreement to facilitate geoengineering. In 2010, policymakers under the Convention on Biological Diversity, placed a de facto global moratorium on studying geoengineering with exceptions for small-scale research studies. While solar geoengineering could have the potential to provide humanity with temporary amnesty from the threats of climate change while mankind attempts to permanently cut carbon emissions, the unknown consequences and consistent upkeep of technology required for success leave many unconvinced. This raises the question: If we limit research on solar geoengineering now, are we preventing humanity from engineering a new climate catastrophe, or failing to discover vital information to buy us time in fighting the current climate catastrophe?
Solar geoengineering research projects have been conducted across the globe, including any technologies that work to block sunlight or reflect sunlight back into space. One of the most controversial technologies is stratospheric aerosol injection — the process of injecting sulfur dioxide particles directly into the stratosphere, mimicking the cooling effects of a volcanic eruption.
The controversy with SAI lies in the fact that the potential good it brings is only matched by its potential for destruction. If we were to begin the process of SAI and then suddenly stop releasing the particles into the atmosphere, termination shock could take place where temperatures rise so rapidly that it could endanger the future of life on Earth. Other side effects of SAI include acid rain, ozone depletion, reduced precipitation, and regional shifts of climate change. Solar geoengineering alone may not be our solution to climate change, but it should be considered as a potential tool to help postpone the climate crisis. Research on geoengineering is essential to better understand our options for reversing climate change.
Geoengineering consequences could be incredibly devastating. But as we get closer and closer to the irreversible tipping points such as the melting permafrost and the Greenland ice sheet, humanity faces an equally significant threat: Anthropogenic climate change could change all life as we know it. Changing weather patterns will be harder to interpret, harming agriculture and potentially causing mass starvation. So, how do we choose the lesser of two evils? We engage in research on solar engineering so, as the threat posed by climate change continues to grow, we are better informed about our choices.
Where and how we research geoengineering is another political question in need of an answer. The Earth’s ecosystems are extremely interconnected, making it hard to test technology in one area without ripple effects throughout environments. To ensure ethical testing, regulations surrounding geoengineering research in the real environment must enforce safe and transparent research.
Due to these possible repercussions, another barrier threatening the advancement of SAI research is the lack of public support. A group of Harvard researchers attempted an experiment known as the Stratospheric Controlled Perturbation Experiment in 2021. SCoPEx was a privately funded experiment, but the team was publicly transparent with all research plans. After six years of preparation, the research team was ready to test run their mechanisms in Kiruna, Sweden without releasing any materials into the atmosphere. Despite the trial run releasing no materials into the atmosphere, letters from Swedish environmental organizations and the Indigenous Saami Council demanded the project be canceled, calling the experiment’s plans a “moral hazard.” Although the results of SCoPEx would have given us a better understanding of both the risks and benefits of solar geoengineering, due to the intense backlash, the project was postponed until 2022, and eventually canceled in March of 2024.
Many environmentalists including Greta Thunberg argue against projects such as SCoPEx claiming geoengineering is not the path forward for combating climate change. Solar geoengineering is seen by many as an excuse for big oil and gas companies to continue to emit large amounts of greenhouse gasses, but it could also serve as a tool to be used in tandem with curbing our emissions to net zero. A combination of solar geoengineering and emissions reductions could be a sustainable long-term solution.
Large geoengineering processes such as SAI necessitate cooperation between many stakeholders. In 2022, Making Sunsets, a solar geoengineering startup, launched an unauthorized geoengineering research project in Baja California, Mexico. The company released balloons filled with sulfur dioxide particles, a form of stratospheric aerosol injection, without government authorization. The co-founders, Luke Iseman and Andrew Song describe SAI as sunscreen for the Earth and encourage people to be a part of the solution and buy cooling credits. Yet, this unauthorized and simplistic approach led Mexico to completely ban solar geoengineering — a sign that researchers and policymakers must work together for geoengineering to become a possibility.
While Mexico has prohibited any solar geoengineering research within its territory, the rest of the world institutes limited policy and oversight. A 2023 report mandated by the U.S. Congress took a very cautionary approach to geoengineering and created no plan to develop a research program. Additionally, the EU called for an analysis of geoengineering last year and resolved that a “comprehensive scientific review process” would be essential to moving forward with geoengineering. Global policies around solar geoengineering were first put into place in 2010 through decision X/33 which enforces a de facto moratorium on geoengineering activities that could affect ecosystems and biodiversity until there is sufficient enough evidence and justification that geoengineering should take place. The decision emphasizes the need for international cooperation and public participation in the conversation surrounding solar geoengineering. Yet, the current acceleration of climate change in the past decade may necessitate a reevaluation X/33.
Eliminating greenhouse gas emissions is the key to stopping climate change, but once the earth’s tipping points are reached there is no going back. The use of SAI in tandem with cutting emissions might serve as the best tool we have to “turn back the temperature clock” and postpone climate change. The question remains, though, if the possible consequences of geoengineering outweigh the time that it could buy us.
As Earth enters the sixth mass extinction and our degrees of warming inch closer to the 1.5 and 2° C mark, geoengineering may become inevitable to prevent future climate-induced calamities. While we must continue to curb greenhouse gas emissions, if we encourage solar geoengineering research now, we will understand all the risks and consequences involved in order to make the most educated decision in the future.
