CERN Seizes Opportunity After China Shelves 100 km Collider, Clearing Way For Europe’s FCC

CERN's director-general, Fabiola Gianotti, says Beijing's recent decision to pause its proposed 100-kilometre Circular Electron Positron Collider (CEPC) creates a "window of opportunity" for Europe to press ahead with its own successor to the Large Hadron Collider (LHC).

The CEPC, first announced a decade ago, would have been the world's largest particle accelerator. By contrast, the LHC — a 27-kilometre ring that runs roughly 100 metres below the Franco‑Swiss border — remains the largest operating collider and was instrumental in the discovery of the Higgs boson in 2012.

What CERN Is Proposing

CERN is developing plans for the Future Circular Collider (FCC): a 91-kilometre ring to be built about 200 metres underground. The FCC is designed to extend particle-physics research beyond the LHC's lifetime, probing fundamental questions such as the nature of dark matter and dark energy — the unseen components that are thought to make up roughly 95% of the universe's energy and matter.

The estimated price tag for the FCC is around $17 billion. The project is still awaiting formal approval from CERN's 25 member states, although the CERN Council issued a very positive opinion on the feasibility study on November 7, assessing geological, territorial, technological, scientific and financial aspects. If timelines hold, approval could come in 2028 and the FCC might be operational in the late 2040s.

China's Pause and Its Implications

Gianotti told journalists that the Chinese Academy of Sciences has decided to back a smaller, lower-energy collider instead of the full-scale CEPC for now. Wang Yifang, director of the Institute of High Energy Physics in Beijing, confirmed the CEPC is not in China’s next five-year plan and said China may resubmit the project for consideration in 2030 — or, if the FCC is approved first, seek to join CERN’s effort instead.

"This is an opportunity," Gianotti said, noting that an approved Chinese project would likely have started sooner than the FCC and could have created direct competition. "If the FCC is approved, the Chinese would abandon their project to come and work with us," she added.

Gianotti’s five-year term ends in December; she will be succeeded by British physicist Mark Thomson.

Support, Cost, And Local Opposition

Supporters argue the FCC would keep Europe at the forefront of particle physics and enable experiments that could illuminate the unseen components of the cosmos. Opponents — including the Co‑cernes collective, which represents local residents and environmental critics — say the size, cost and social and environmental impacts of the required excavation are excessive. Co‑cernes has pointed to China’s decision as evidence to question the FCC’s necessity.

For now, CERN sees China’s pause as a strategic opening to consolidate international collaboration and secure approval for the FCC. The coming years will determine whether Europe moves ahead alone, wins broader global partners, or merges efforts with Chinese scientists should they opt to join the FCC programme.