CERN's proposed Future Circular Collider (FCC), a large-scale project in particle physics, is at the heart of an intense public debate. Objections raised include an "unacceptable carbon footprint," the requirement for two EPR nuclear reactors for its operation, an estimated cost of billions of euros that could be reallocated to other priorities, and claims of unclear scientific objectives. This discussion, which emerged in the summer of 2026 within the Particles and Fields Division of the French Physical Society, questions whether a collider of this magnitude is compatible with efforts to combat climate change.

A recent essay addresses these criticisms, confronting emotionally charged concerns with an analysis based on orders of magnitude and a clear scientific vision. The study distinguishes between a project's immediate carbon footprint and its full balance sheet, including the costs of postponing or abandoning the initiative. It also explores ways to mitigate its impact, such as the potential use of natural hydrogen, an uncertain prospect. The aim is to provide a solid foundation for the public debate, organized by France's National Commission for Public Debate and the Swiss consultation, targeting a broad audience beyond the particle physics community.

The essay frames the discussion about the FCC as a fundamental choice about the kind of society we want to build: one organized around renunciation and ever-shrinking horizons, or one that transforms its production methods to choose a desirable future. The decision regarding the FCC, therefore, is not solely based on climate considerations, but requires an evaluation of the real consequences of the available choices.