As the world grapples with the escalating effects of climate change, scientists are exploring radical solutions to slow down global warming. Among these are geoengineering technologies—deliberate, large-scale interventions in Earth’s natural systems designed to counteract climate change. These technologies, while promising, are also highly controversial, with debates centered on their effectiveness, risks, and potential to divert attention from essential decarbonization efforts.
Geoengineering strategies are generally classified into two categories: Carbon Dioxide Removal (CDR) and Solar Radiation Management (SRM). CDR methods focus on reducing atmospheric CO2 levels through technologies like carbon capture and storage (CCS) and ocean geoengineering, as well as through afforestation. On the other hand, SRM seeks to reflect a portion of the sun’s energy away from Earth, thereby reducing global temperatures.
A significant milestone in SRM research was reached in April when scientists from the University of Washington conducted the first outdoor test of SRM technology in the U.S. in San Francisco Bay. The experiment involved releasing tiny aerosol particles from a decommissioned aircraft carrier to achieve cloud brightening—a process that alters the composition of clouds over oceans to temporarily cool the Earth. While this localized test was small in scale, it represents a broader trend of SRM experimentation aimed at buying time until meaningful decarbonization can occur.
David Keith, a prominent scientist leading the Climate Systems Engineering Initiative at the University of Chicago, is exploring a more ambitious SRM approach. Keith proposes injecting sulfur dioxide into the stratosphere, inspired by the natural cooling effect observed after volcanic eruptions. For instance, when Mount Pinatubo erupted in 1991, it released 17 million tons of sulfur dioxide into the stratosphere, resulting in a one-degree Fahrenheit drop in Northern Hemisphere temperatures. Keith believes this process could be replicated to mitigate global warming temporarily.
However, the potential risks of such geoengineering approaches are immense. While localized SRM experiments like those in San Francisco Bay may have limited environmental impacts, large-scale interventions in the stratosphere could have unpredictable consequences on global weather patterns. Additionally, the sulfur dioxide used in Keith’s proposed experiment could eventually fall back to Earth, potentially causing respiratory problems and other health issues. Environmentalist David Suzuki has criticized this approach, calling it “arrogant and simplistic,” and warning of the unintended consequences that could arise from such powerful technologies.
Critics also argue that geoengineering, particularly SRM and CCS, could provide a dangerous distraction from the urgent need for decarbonization. By relying on these technologies, governments and companies might delay the transition to green energy, prolonging the use of fossil fuels and undermining efforts to combat climate change at its source. Despite these concerns, both SRM and CCS are attracting significant investment from private companies and governments worldwide. The White House has allocated billions to these technologies, and other political leaders are following suit. However, some regions, like the European Union, are urging caution, calling for thorough risk assessments and the establishment of international regulations before these technologies are widely deployed.
The promise of geoengineering lies in its potential to provide a temporary reprieve from the worst effects of climate change, buying time for the global community to implement long-term solutions. However, this potential comes with significant risks. As these technologies continue to develop, it is crucial to create international standards and regulations to govern their use. Moreover, it is vital to ensure that geoengineering does not divert attention from the critical task of decarbonization, which remains the only sustainable path to addressing climate change in the long run.