Four leading climate scientists have issued a stark warning against solar geoengineering, arguing it does not buy time for decarbonisation and poses grave planetary risks. In a forceful commentary, Raymond Pierrehumbert, Julia Slingo, Michael Mann, and Valerie Masson-Delmotte dismiss the notion that such techno-fixes can offset slow progress on cutting emissions.
Solar Geoengineering: A Dangerous Gamble
The scientists highlight that solar geoengineering proposals, which aim to reduce sunlight, would require decades to build infrastructure and would create a dangerous dependency. If disrupted, a catastrophic 'termination shock' could release pent-up warming rapidly. They stress that carbon dioxide remains in the atmosphere for millennia, while geoengineering effects decay in years, making it a temporary mask that fails to address the root cause.
Flawed Assumptions and Uncharted Risks
Drawing on over a century of collective expertise, the authors note that climate models disagree on required intervention levels and responses. After just 10 years of stratospheric aerosol injection, global cooling could vary from less than 1°C to as much as 3°C – a change more rapid than from CO2 emissions. They call for rigorous scientific scrutiny, similar to that applied to greenhouse gases, before any deployment.
Governance and Profit Motives
The commentary criticises the lack of governance and the rise of venture-capital-funded startups like Stardust and Reflect Orbital, which aim to profit from geoengineering. The authors argue that developing technology without oversight enables unrestricted, profit-driven deployment, diverting resources from genuine decarbonisation efforts.
A Call for Caution
The scientists urge a halt to the 'geoengineering techno-juggernaut' and emphasise that the priority must be ending fossil fuel use. 'When you're in a climate hole, stop digging,' they conclude, warning against playing dice with the planet's future.
