Scientists Warn Against Solar Geoengineering as "Termination Shock" Looms

Leading climate researchers caution that unregulated geoengineering could backfire catastrophically.

On June 19, 2026, climate scientists Raymond Pierrehumbert, Julia Slingo, Michael Mann, and Valerie Masson-Delmotte published an article in The Guardian sharply criticizing solar geoengineering schemes. They highlighted the risk of "termination shock"—the dangerous rapid climate change that would occur if geoengineering were halted after starting.

The scientists argued that current funding is skewed toward engineering deployment rather than foundational science, governance, or ethics. They warned this research is often pursued by for-profit companies without adequate oversight.

"It is the height of folly to invest in developing the technology… that only serves to enable unrestricted, profit-motivated deployment by outfits such as Stardust."

Stalled Talks and Scientific Backlash

During climate talks in Bonn ahead of COP 31, UN climate chief Simon Stiell accused some nations of stalling. Saudi Arabia and India reportedly objected to language reaffirming climate science, drawing sharp criticism from Pacific Island representatives.

"We have seen side-stepping and stalling… We simply cannot afford to reopen previous decisions, to renegotiate existing targets, or to backslide."
— Simon Stiell, UN climate chief

Sivendra Michael, speaking on behalf of Pacific Island nations, was unequivocal:

"We are hearing voices in these rooms that are doing their best to undermine science. Anyone blocking references to science, they are not our friends."

Governance Gaps and Private Sector Push

The article states that solar geoengineering research by entities such as the UK's Aria agency and startups like Stardust and Reflect Orbital is proceeding without adequate governance or scientific understanding of regional impacts.

The scientists, all affiliated with the Royal Society or similar institutions, have previously contributed to IPCC reports and national academy assessments on solar geoengineering. They urge that climate action focus on reducing fossil fuel use rather than pursuing unproven technological fixes.