Solar geoengineering, a controversial concept, could have devastating consequences if it falls into the wrong hands, scientists warn. The report highlights the potential for increased North Atlantic hurricanes, the decline of the Amazon rainforest, and droughts in Africa if solar geoengineering is deployed in specific regions by rogue actors. However, if implemented globally and coordinated over decades or centuries, it could lower global temperatures, according to the UK's Royal Society review. The world's failure to address the climate crisis necessitates a critical decision: whether to embrace geoengineering as a temporary solution or continue with the current path, which is already claiming lives and livelihoods. The logistics of large-scale geoengineering are daunting, but its cost is relatively small compared to climate action. The researchers emphasize that geoengineering only treats the symptoms of climate change, not the root cause: the burning of fossil fuels. Abruptly halting geoengineering without reducing emissions could lead to a 'termination shock,' causing temperatures to rise rapidly by 1-2C within a few decades, severely impacting vulnerable ecosystems and populations. Prof. Keith Shine, from the University of Reading, underscores the need for a scientifically informed, globally coordinated strategy to mitigate risks. The scientific community remains divided on geoengineering research, with some advocating for continued study to understand its effects and others warning of increased chances of deployment. The Royal Society report focuses on two feasible and effective methods: stratospheric sulfur dioxide injection and marine cloud brightening. The former, using high-altitude aircraft to pump sulfur dioxide into the stratosphere, creates reflective particles that bounce sunlight back into space. Volcanic eruptions, like Mount Pinatubo's 1992 eruption, provide natural examples, with a similar impact on global temperatures. Marine cloud brightening, on the other hand, involves throwing salt particles into the lower atmosphere to enable cloud formation. However, the global climate system's complexity means that regional deployment of geoengineering can have unintended consequences. For instance, stratospheric sulfur dioxide injection in the southern hemisphere could intensify North Atlantic hurricanes, while deployment in the northern hemisphere might cause droughts in the Sahel region of Africa. Marine cloud brightening in the southeast Atlantic could lead to Amazon dieback, releasing vast amounts of carbon, while deployment in the eastern Pacific could trigger a powerful La Niña event. Prof. Jim Haywood from the University of Exeter emphasizes the importance of international coordination to avoid regional conflicts of interest. The concern arises from commercial companies raising millions to pursue private geoengineering efforts, raising questions about transparency and potential misuse. Even with global agreement, 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 explore the potential of solar geoengineering. However, past experiments have faced strong opposition, highlighting the need for careful consideration and public debate.
