Photo: Knowable Magazine Science Graphic
When I first wrote about geoengineering in 2012, it was viewed as unlikely and unfeasible. However, over a decade later, there is growing interest and support within the scientific community for further research into geoengineering – the intentional manipulation of the climate system to mitigate global warming. Solar geoengineering, in particular, has garnered much attention as a strategy to reflect sunlight away from Earth in order to cool the planet.
Why is there increasing support for solar geoengineering research? Initially, many scientists and experts were hesitant to explore geoengineering research, fearing it would detract from efforts to reduce emissions. Some politicians even proposed it as an alternative to emission cuts. The uncertainty surrounding the potential impacts of geoengineering on the climate system and ecosystems fueled controversy.
Despite these concerns, prominent figures such as James Hansen and a group of over 60 scientists are advocating for more research into solar geoengineering. Major institutions like the US National Academy of Sciences and environmental organizations like the Environmental Defense Fund and the Union of Concerned Scientists also back this call for research. The urgency stems from the realization that current efforts to reduce carbon emissions are insufficient to mitigate the escalating climate crisis.
Recent studies have shown that the planet is warming faster than previously predicted due to decreased sulfur dioxide emissions, leading to an accelerated rise in global temperatures. This accelerated warming could trigger catastrophic climate events and push the planet beyond critical tipping points. In light of these risks, solar geoengineering is being considered as a potential last resort strategy to prevent irreversible climate damage.
Solar geoengineering techniques, such as stratospheric aerosol injection (SAI) and marine cloud brightening, have been proposed as ways to temporarily counteract global warming by reflecting sunlight away from Earth. While these strategies may offer rapid results in cooling the planet and buying time for emission reduction, they do not address key issues like ocean acidification.
The uncertainties surrounding large-scale deployment of SAI are a major point of contention, as there is limited empirical data on the potential effects of these interventions. Modeling studies have shown that SAI could have unintended consequences such as ozone depletion, altered precipitation patterns, and disruptions to agriculture and ecosystems. The impacts of SAI would vary depending on deployment methods, location, and environmental conditions.
Despite the challenges and risks associated with solar geoengineering, proponents argue that further research is crucial to understand the potential benefits and drawbacks of these strategies. While the costs and logistics of deploying SAI on a global scale are significant, the potential benefits in mitigating climate impacts may justify continued exploration of solar geoengineering as a tool to combat climate change.
