Scientists warn solar geoengineering could trigger catastrophic 'termination shock'
Four leading climate scientists caution that solar geoengineering poses grave risks, including a 'termination shock' if the system is halted, and highlight insufficient research and lack of governance.
Four prominent climate scientists – Raymond Pierrehumbert (University of Oxford), Julia Slingo (former UK Met Office chief scientist), Michael Mann (University of Pennsylvania), and Valerie Masson-Delmotte (Climate and Environmental Sciences Laboratory, France) – have issued a stark warning about solar geoengineering.
They note that carbon dioxide remains in the atmosphere for millennia, while solar geoengineering effects decay in years. Building the necessary infrastructure would take up to two decades, after which humanity would become completely dependent on its maintenance. If circumstances forced its cessation, a 'termination shock' would release pent-up warming catastrophically fast.
The scientists argue that current climate models are unreliable. After just 10 years of identical stratospheric aerosol injection, global cooling could range from less than 1°C to as much as 3°C – faster than any observed change from CO2 emissions. Small-scale experiments cannot answer key questions about risks, they say.
They also criticize funding priorities. The UK's Aria agency has a £60 million geoengineering programme focused on technology development in collaboration with for-profit companies, rather than basic science. For instance, the Israeli-US startup Stardust has received over $60 million in venture capital, aiming for near-term deployment. Another firm, Reflect Orbital, plans to place giant mirrors in low Earth orbit.
All of this is happening without any governance framework. The scientists call for the same scientific diligence applied to greenhouse gas research, urging that instead of relying on 'quick fixes,' society should cut fossil fuel use.
