Back to Headlines
Environment
Jun 19, 2026
Analyzed by GPT OSS 120B

Termination Shock: Experts Warn of Planetary Risks from Geoengineering

AI Summary
Leading climate scientists warn that large‑scale geoengineering, especially solar radiation management, could trigger a catastrophic ‘termination shock’ if halted. They stress the lack of governance, the high financial stakes, and the urgent need to focus on decarbonisation instead.

In a joint commentary, four eminent climate experts—Raymond Pierrehumbert, Julia Slingo, Michael E. Mann and Valerie Masson‑Delmotte—sound an alarm over the accelerating push for geoengineering solutions, warning that premature or uncontrolled deployment could plunge the planet into rapid warming once the interventions stop.

The Growing Push for Solar Geoengineering and Its Technical Premises

The Guardian series highlights a surge in proposals to offset carbon‑driven warming by reducing sunlight, chiefly through stratospheric aerosol injection. While proponents tout the ability to “turn it on and off,” the authors argue that the required infrastructure would take up to two decades to build, creating a long‑term dependency that masks, rather than solves, the underlying carbon buildup.

Cost and Funding Landscape of Geoengineering Initiatives

Public and private financing is already flowing into the sector. The UK’s £60 million ARIA programme is earmarked for technology development, often in partnership with for‑profit firms. Meanwhile, the Israeli‑US startup Stardust has secured over $60 million in venture capital, and companies like Reflect Orbital are planning satellite‑based mirrors, all with minimal regulatory oversight.

Potential Climate and Governance Risks of Deployment

Experts stress that solar geoengineering could trigger a “termination shock” – a rapid, catastrophic temperature rise if the program is halted. Model simulations show a wide range of outcomes, from less than 1 °C to more than 30 °C of cooling for the same aerosol injection, underscoring profound scientific uncertainty. Moreover, the lack of a robust governance framework means private actors could deploy technologies without public scrutiny, raising ethical, legal, and geopolitical concerns.

Future Outlook: Governance Gaps and the Need for Caution

The authors call for the same level of scientific diligence applied to greenhouse‑gas mitigation to be extended to geoengineering research. Without rigorous modelling, inter‑comparison studies, and international governance, the sector risks becoming a profit‑driven “techno‑juggernaut” that diverts resources from essential decarbonisation efforts. The consensus is clear: stop digging the climate hole by burning fossil fuels before attempting to “reboot” the planet with untested hacks.

  • Raymond Pierrehumbert – Professor of planetary science, University of Oxford; lead author of IPCC AR3 and US National Academy report on solar geoengineering.
  • Julia Slingo – Former chief scientist of the UK Met Office; recipient of the Rossby Medal and nine honorary doctorates.
  • Michael E. Mann – Presidential Distinguished Professor, University of Pennsylvania; member of the US National Academy of Sciences.
  • Valerie Masson‑Delmotte – Director of research, Climate and Environmental Sciences Laboratory; co‑chair of IPCC Working Group 1 for AR6.