4 Climate Scientists Warn Geoengineering Could Trigger 3C Cooling Swings Without Governance
Updated
Updated · The Guardian · Jun 21
4 Climate Scientists Warn Geoengineering Could Trigger 3C Cooling Swings Without Governance
3 articles · Updated · The Guardian · Jun 21
Summary
Four senior climate scientists said solar geoengineering could leave the planet dangerously dependent on decades of maintenance, with any forced halt risking a rapid “termination shock” as masked warming returns.
Two decades may be needed to build deployment infrastructure, they wrote, while carbon dioxide persists for centuries to millennia—making geoengineering a temporary mask rather than a substitute for cutting emissions.
After just 10 years, modelled stratospheric aerosol injection produces outcomes ranging from less than 1C to as much as 3C of global cooling, which the authors say shows scientists are still “flying blind.”
£60 million from the UK’s Aria program and more than $60 million raised by startup Stardust illustrate how funding is shifting toward deployable technology and for-profit ventures despite unresolved ethics and governance gaps.
The authors argue that geoengineering is diverting money and attention from the core task of phasing out fossil fuels, while no credible global framework exists to regulate planetary-scale intervention.
With decarbonization lagging, is it more dangerous to develop geoengineering or to leave it off the table entirely?
If a rogue company deploys geoengineering, what power does any nation have to stop a potential global catastrophe?
Who gets to control the Earth's thermostat, and what happens to those who disagree with the setting?
Solar Geoengineering in 2026: Uncontrolled Risks, Governance Gaps, and the Looming Threat of Extreme Climate Swings
Overview
As the world faces escalating climate challenges, highlighted by record-breaking heat events like Phoenix’s 105°F in March 2026, the idea of geoengineering—reflecting part of the sun’s rays to cool the planet—has shifted from fringe to serious debate. This approach is gaining attention as a possible last resort to prevent catastrophic climate tipping points, such as the collapse of ocean currents or ice sheets, which are increasingly likely if current warming trends continue. However, the potential for misuse and unpredictable consequences makes careful consideration and global oversight essential before any deployment.