Solar Geoengineering

In 1991, Mount Pinatubo's volcanic eruption in the Philippines had a significant impact on global temperatures. The eruption released an ash plume that reached the stratosphere, forming a layer of aerosol particles. This layer acted as a solar umbrella, reflecting sunlight away from the Earth and causing a temporary cooling effect of about half a degree Celsius for nearly two years.

The concept of replicating this phenomenon, known as solar geoengineering, has sparked interest among scientists as a potential tool to combat global warming. Proponents argue that it is a critical avenue to explore as climate change worsens and the need to reduce suffering becomes paramount. However, critics believe that the risks associated with solar geoengineering outweigh its potential rewards and argue against it as a response to global warming.

Solar geoengineering aims to cool the planet by reflecting sunlight away from the Earth's surface. The most extensively researched approach involves injecting aerosols into the stratosphere, mimicking the effect of volcanic eruptions. Some scientists are also exploring methods such as brightening marine clouds to enhance their sun-reflecting capabilities. Additionally, the concept of using reflective shields in outer space is being considered. However, implementing these technologies on a large scale would require interfering with our complex climate system.

One of the main reasons for supporting solar geoengineering is the urgency of our current situation. Despite efforts to reduce carbon dioxide emissions, they continue to rise, posing ongoing climate risks. Cutting emissions to zero would only stabilise the climate without eliminating the existing risks. Therefore, proponents argue that alongside emission reduction, we must explore climate processes, conduct computer modelling, and develop technology to assess the potential effectiveness and safety of solar geoengineering as part of a broader solution.

However, the complexity of the global climate system raises concerns about the unpredictable changes that solar geoengineering could induce. Introducing new elements into the atmosphere or stratosphere could disrupt precipitation patterns and exacerbate the extreme weather events already linked to climate change. This risk is acknowledged by nearly everyone involved in the debate.

Moreover, solar geoengineering requires long-term commitment and global cooperation. While the effects of carbon dioxide emissions can persist for thousands of years, the cooling effect of solar geoengineering methods lasts only for a short time. Achieving a sustained cooling effect would necessitate constant deployment over centuries. This poses challenges in terms of institutional frameworks and treaties that can be adhered to for such an extended period, with termination shock being a potential consequence if the deployment is abruptly halted.

The governance of solar geoengineering is also a contentious issue. Concerns about its potential negative impact on decarbonization efforts and the possibility of providing an excuse for continued fossil fuel consumption have been raised. The technology's deployment at a time when efforts to reduce emissions are just beginning could undermine the urgency of decarbonization. While these concerns are acknowledged, there is a division regarding the best path forward.

The debate surrounding solar geoengineering has led to calls for non-use agreements, limits on outdoor experiments, and the avoidance of public funding and support from international institutions. Scientists and researchers have voiced different opinions on the extent of research, with some advocating for low-risk fundamental studies while opposing technology development that could lead to deployment. Others argue for robust scientific assessments and experiments to gather useful information while maintaining caution.

Currently, solar geoengineering research primarily takes place in labs through models and simulations. The question of how far research should progress is at the forefront of the discussion. Calls for a balanced approach and international scientific assessments have emerged, with diverging opinions on the level of experimentation. Striking a balance between gaining knowledge and preventing the premature deployment of solar geoengineering remains a key challenge.

Ultimately, the disagreement over solar geoengineering reflects the deep concern and commitment shared by those involved in climate-related research and advocacy. While the path forward may not be clear, the tension between differing viewpoints can foster a more thoughtful and rigorous approach to address the pressing challenges of climate change. As assessments and recommendations by world organisations focused on climate emerge, further discussion and research will shape the future of solar geoengineering.