This essay examines whether building the proposed Future Circular Collider (FCC) at CERN should be abandoned on climate grounds. The authors lay out the main criticisms—its estimated carbon footprint, its power needs, human-health estimates tied to emissions, its cost, and doubts about how much new science it would deliver—and then test each charge against numbers and choices. They argue that the decision cannot rest on a single visible symbol. Instead it must weigh the FCC’s environmental costs against its scientific benefits and realistic alternatives.

Patrick Janot and Christophe Grojean wrote the piece for public consultations in France and Switzerland. They bring together earlier essays and public documents to answer a set of specific complaints that surfaced in 2026 debate. The analysis focuses on climate impacts alone and is meant for a wide readership, not only specialists. The authors make clear that the views are their own and not an official CERN position.

The paper lists the main criticisms in concrete terms. Current, still-incomplete estimates put the FCC’s construction and operation at about one to two million tonnes of carbon dioxide equivalent (CO2e). Opponents say the collider’s electricity needs would be comparable to the output of two EPR reactors (European Pressurized Reactors). One statistical argument linked to health converts emissions into premature deaths using a rule of roughly one death per 4,000 tonnes of CO2e, producing the headline figure of about 500 deaths. Critics also say the collider could just produce far more data rather than a clear, new discovery, and that the billions it would cost might be better spent on lower-carbon priorities.

The authors do not dismiss these concerns. They point out a common mistake: assigning blame by where emissions are counted, rather than by where emissions can be avoided. Large emitters and whole supply systems matter more than a single project’s footprint. The essay urges comparing orders of magnitude, measuring what would be lost if the project were cancelled, and weighing feasible ways to cut the collider’s impact—such as different energy sources or technical changes—before deciding.