"It's Time To Talk About Geoengineering" - No, Actually It's Time To Talk About Termination Shock [View all]

Ed. - This piece was written by four climate scientists, including Michael Mann and Raymond Pierrehumbert, who, in short, know what they're talking about - IOW, it's not your typical op-ed.

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The essential thing to understand is that carbon dioxide, once emitted, is only very slowly removed from the atmosphere. A sizable share of it will still be keeping Earth dangerously hot millennia from now. Solar geoengineering proposals involve injection of substances whose effect, by contrast, decays in a matter of years. Some might think this is an advantage of solar geoengineering. We can turn it on and off quickly when the damage it is doing to our planet becomes clear, right? Wrong.

Recent analyses demonstrate that it would take as long as two decades to create the required infrastructure. By then we would completely reliant on maintaining it – a tall task in a dangerous world with global conflict. It would only temporarily mask the pent-up warming implicit in the ongoing buildup of carbon dioxide, and this pent-up warming would be released in a catastrophically rapid “termination shock” if circumstances force the cessation of solar geoengineering. So solar geoengineering does not “buy time” for decarbonisation. The same can be said for other geoengineering schemes, which also require sustained maintenance over centuries to millennia. Five hundred years from now, the fabled Bering dam may crumble, but the carbon dioxide wreaking havoc on the climate system will still be there waiting.

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Even more ominous is the explicit entry of venture-capital funded for-profit startups seeking to make money from solar geoengineering deployment in the near future. The Israeli-US startup Stardust has received more than $60m in venture capital, and their business model assumes near-term deployment. And then there’s Reflect Orbital which wants to put giant mirrors in low Earth orbit; they are pitching sales of illumination rather than solar geoengineering, but the technology is identical and we doubt it will be long before they try to get in on the “cooling credits” game.

All of this is happening in the total absence of governance. There are pious calls for governance from some of the pro-geoengineering researchers, but what is the path to get there? Is it governable at all? It is the height of folly to invest in developing the technology – even if we knew what might work – that only serves to enable unrestricted, profit-motivated deployment by outfits such as Stardust. As private companies whose technology is subject to little regulation, they and their backers have no legal obligations to submit themselves to public scrutiny nor to provide any assurances on ensuing climate impacts. Will these technologies be carried out devoid of any serious scientific understanding of the consequences and of social, legal and political concerns?

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https://www.theguardian.com/commentisfree/2026/jun/19/solar-geoengineering-risk-to-planet-earth