Summary
- C40 says 41 cities across six continents have backed the Global Urban Data Centres Pact.
- European signatories include London, Barcelona, Copenhagen, Heidelberg, Milan, and Oslo.
- The pact links data centre planning with energy systems, water, heat, land, costs, and community benefit.
C40 Cities has launched the Global Urban Data Centres Pact, giving city leaders a shared framework for managing data centre development as AI-driven demand increases pressure on urban power, water, land, and heat systems.
The pact was launched during London Climate Action Week and is backed by 41 cities across six continents, representing more than 90 million people. European signatories include London, Barcelona, Copenhagen, Heidelberg, Milan, and Oslo.
The framework asks that future data centres be strategically integrated into cities, sustainable and resource efficient, engaged with local communities, and designed to support cost security and shared prosperity. C40’s pact page sets out the principles and examples from participating cities.
Urban patience is narrowing
Data centres have long relied on cities and their edges for connectivity, customers, labour, and access to power infrastructure. The AI build-out is changing the scale of that relationship. Facilities that once sat mainly inside technical and real estate discussions are now being debated as large electricity users, water users, heat sources, and land competitors.
Mayors are being pulled between digital infrastructure investment and resident concerns over utility costs, grid pressure, water consumption, noise, local heat, and whether community benefits match the infrastructure burden. The pact reflects a political shift in which local authorities are starting to set conditions rather than simply respond to development applications.
C40’s materials refer to more than 1,700 data centres already operating in C40 cities, with more coming online each month. That concentration makes urban planning rules a direct constraint on the next stage of digital infrastructure growth. The question is not whether cities need data centres, but how much load they can accept, where facilities should sit, and what infrastructure must accompany them.
London’s involvement gives the pact direct UK relevance. West London has already shown how data centre load can collide with housing, grid reinforcement, and local planning priorities. Other European cities face different but related pressures, from water stress and land scarcity to heat-network integration and electricity price exposure.
Planning moves into the utility layer
The pact treats data centres as part of city systems rather than standalone buildings. A modern facility may have efficient cooling and strong sustainability credentials, but it still connects to a specific grid, occupies land, draws or avoids water depending on design, rejects heat, requires network access, and changes local infrastructure requirements.
That system view will change planning submissions. Developers will need to show how a project sits within local energy strategies, grid reinforcement plans, heat network opportunities, water policy, transport access, construction logistics, and workforce objectives. A technically viable site may struggle if it cannot show a credible local role.
Heat reuse is likely to become one of the strongest planning themes in colder European markets. Data centres can provide low-grade heat, but useful deployment depends on nearby demand, pipework, temperature, commercial arrangements, and long-term operation. City-led frameworks can turn heat reuse from a voluntary talking point into a condition of acceptance where networks exist.
The pact could also influence investors. Markets with clearer city rules may be easier to diligence because the planning expectations are visible earlier. Markets with late-stage political opposition may carry more development risk, even where demand and power appear attractive.
The industry has often described data centres as critical digital infrastructure. Cities are now applying the logic that follows from that label. Critical infrastructure needs planning discipline, cost allocation, community explanation, and clear performance expectations.
The pact’s force will depend on whether signatory cities embed its principles into planning guidance, zoning, utility negotiations, and development agreements. If they do, urban data centre development will be judged through power, water, heat, cost, and community value long before a building reaches commissioning.
