Solar geoengineering, a controversial concept, has sparked intense debate among scientists and policymakers alike. While some view it as a potential solution to the climate crisis, others warn of dire consequences if it falls into the wrong hands. The latest research highlights the dual nature of this technology, emphasizing both its potential benefits and risks.
The report, published by the UK's Royal Society, reveals that solar geoengineering could have devastating effects if deployed unilaterally by rogue actors. It warns that this approach might intensify North Atlantic hurricanes, jeopardize the Amazon rainforest, and exacerbate droughts in parts of Africa. However, the study also underscores the potential benefits of global and coordinated implementation.
When applied globally and consistently over decades or centuries, solar geoengineering could significantly lower global temperatures, according to the report. This finding raises a critical question: in a world failing to adequately address the climate crisis, should we prioritize geoengineering as a temporary measure, or should we focus on more immediate and sustainable solutions?
The report's authors emphasize that geoengineering is not a panacea. It merely masks the symptoms of climate change, such as rising temperatures, without addressing the root cause: the burning of fossil fuels. Therefore, geoengineering should be seen as a complementary strategy to cutting emissions, not a replacement.
Abruptly halting geoengineering efforts without reducing emissions could lead to a 'termination shock,' resulting in a rapid temperature rise of 1-2 degrees Celsius within a few decades. This would have severe consequences for both human populations and ecosystems that cannot adapt quickly enough.
Prof. Keith Shine, a leading expert in the field, underscores the importance of a scientifically informed, globally coordinated, and internationally agreed-upon strategy. He suggests that the decision to deploy geoengineering should be made only when the risks are deemed less severe than the risks associated with insufficient climate change mitigation.
The scientific community remains divided on the issue. Some researchers advocate for continued research to enhance our understanding of geoengineering's effects, preparing for potential future needs. Others argue that further research could increase the likelihood of its deployment, as it may be perceived as a rapid solution to the climate crisis.
The Royal Society's report focuses on two feasible and effective geoengineering methods. One involves using high-altitude aircraft to inject sulfur dioxide (SO2) into the stratosphere, creating reflective particles that bounce a fraction of the sun's heat back into space. Historical volcanic eruptions, such as Mount Pinatubo's eruption in 1992, have demonstrated the cooling effect of this process.
The second method, marine cloud brightening, involves injecting salt particles produced from seawater into the lower atmosphere. These particles enable water vapor to form clouds, reflecting sunlight. This process is already observable in the ribbons of clouds created by shipping pollution.
The report highlights the complex global climate system and the potential consequences of unilateral geoengineering efforts. Deploying sulfur dioxide injection only in the southern hemisphere could intensify North Atlantic hurricanes. Focusing on the northern hemisphere might lead to droughts in the Sahel region of North Africa, while tropical deployment could cause droughts in the Mediterranean.
Furthermore, marine cloud brightening in the southeast Atlantic could result in the dieback of the Amazon, releasing vast amounts of carbon. Deployment in the eastern Pacific could trigger a massive La Niña event, with far-reaching global implications.
Prof. Jim Haywood, a member of the Royal Society team, emphasizes the importance of avoiding unilateral action by rogue actors. Such actions could have unintended consequences, as individuals might attempt to reduce temperatures in one region, potentially disrupting global climate patterns.
Despite the potential risks, some commercial companies have raised significant funds to pursue private geoengineering initiatives. Prof. Shine stresses the need for objective, critical, and transparent research, raising concerns about commercialization if it falls short of these standards.
The scientists acknowledge that even with a globally coordinated deployment, uncertainties persist regarding the extent of cooling and regional impacts. The UK's Advanced Research and Invention Agency has launched a £50 million geoengineering program, including small-scale outdoor experiments, to address these uncertainties.
However, the history of geoengineering experiments is not without controversy. Previous outdoor experiments have been canceled due to strong opposition, underscoring the need for careful consideration and public engagement in the decision-making process.
