London, UK (23 June 2026) – Data centres, the infrastructure powering the global digital economy, are being built in cities worldwide at unprecedented speed. In many cases, residents fear that this rapid growth risks pushing up energy costs, straining water supplies and electricity grids and adding more urban heat to neighbourhoods.
Key highlights
- Global Urban Data Centres Pact launches at London Climate Action Week
- 41 mayors from six continents, representing more than 90 million people, address residents’ concerns about the rapid rise of AI and digital infrastructure in cities, pledging that growth will not be detrimental to communities or the planet
- Mayors across the world call on the data centre and AI industry to work with them to create a more sustainable and equitable future
- Rapid growth means there are now over 1,700 data centres in C40 cities, with more coming online each month
A global commitment to sustainable data centres
The Pact’s founding signatories represent a combined population of more than 90 million people
So today, for the first time, 41 cities across six continents are setting a different course: at London Climate Action Week, city leaders will launch the Global Urban Data Centres Pact, a shared commitment, not to reject data centres, but to ensure any future expansion delivers cleaner energy, lower costs, and healthier communities for all.
Backed by cities including Barcelona, Johannesburg, London, Miami, Rio de Janeiro, Phoenix and Melbourne, the Pact’s founder signatories represent a combined population of more than 90 million people.
The Pact responds to the sharp rise in the development of data centres in cities, supercharged in recent years by the AI boom. As urban data centres expand, mayors are finding themselves on the frontline, between resident concerns and industry ambition, as they look to manage energy use, heat impacts and local pressures on land, water and power systems. The Pact also provides a clear roadmap for how companies and investors can work with cities and avoid having their applications to build denied.
What the Pact calls for
From heat reuse in northern Europe to water-conscious cooling in drought-prone regions, cities are already leading the way
The Global Urban Data Centres Pact sets a clear vision of the conditions that mayors believe are essential for sustainable, high-performing urban data centres that work for cities and their residents, as well as investors and companies. The Pact calls for data centres that are:
- strategically integrated into cities,
- sustainable and resource efficient,
- engaged with the local community
- focused on driving down costs and shared prosperity for cities.
Cities are already demonstrating how their leadership can harness the potential of the digital economy while protecting our environment and serving our residents. From heat reuse in northern Europe to water-conscious cooling in drought-prone regions, incentives to utilise clean energy, and reinvestment in affordable housing: practical solutions are being pioneered by cities around the world. The Pact brings these approaches together and scales them across a global network.
What city leaders are saying
Kate Gallego, Mayor of Phoenix and C40 Cities Vice Chair, said:
“Like many American cities, Phoenix has experienced first-hand the significant expansion of AI and digital economy infrastructure.
“While data centres can power important advancements, rapid growth also brings important responsibilities. Residents expect local leaders to ensure development is planned carefully, infrastructure keeps pace, and surrounding communities share in the benefits.
“That’s why Phoenix has been proud to help turn this Pact from an idea into a reality. By bringing together cities from around the world, we’re creating a practical framework to support continued innovation while helping ensure this new infrastructure is developed in a way that strengthens communities and improves quality of life for all.”
Nicholas Reece, Lord Mayor of Melbourne and C40 Cities Vice Chair, said:
“In the race to become smart cities, we don’t want to ruin the planet – that simply isn’t smart.
“In Melbourne, we believe cities should help shape the future of digital infrastructure instead of reacting to it.
“Local communities should be involved in decisions that affect them, which means growth must be matched by responsible planning, sustainable resource use and genuine community benefits.
“We’re proud to work alongside Phoenix and dozens of cities around the world to develop the Global Urban Data Centres Pact. This is a big deal, and shows how cities can learn from one another, share practical solutions and help build a digital future that is innovative, sustainable and works for local communities.”
Mayor of London and C40 Co-Chair Sadiq Khan, said:
“My ambition is for London to become the world’s leading city for environmentally friendly, low emission, high efficiency data centre development.
“AI and digital infrastructure will play a major role in the future prosperity of cities around the world, but residents are right to expect growth to be managed responsibly.
“That’s why I am proud to see cities coming together through the Global Urban Data Centres Pact to help shape a model for growth where innovation, sustainability and the interests of local communities go hand in hand.
“By working together across borders, cities can learn from each other and help build a cleaner, fairer and more prosperous future for everyone.”
Haris Doukas, Mayor of Athens, said:
“The rapid development of data centres, cloud services, and AI infrastructure presents significant opportunities for innovation and economic growth.
“At the same time, it highlights the need for careful stewardship of energy, water, land, and critical urban infrastructure.
“As countries such as Greece accelerate investment in digital infrastructure, it is increasingly important that development is guided by transparency, resource efficiency, and alignment with local sustainability objectives.”
Brandon Johnson, Mayor of Chicago, said:
“In Chicago, we believe that true innovation cannot come at the expense of health, safety, or our natural environment.
“We are proud to join our fellow cities around the world in signing this pact; with it, we are reinforcing our commitment to working with community and industry stakeholders to develop policies and protocols that safeguard public health and wellbeing and mitigate environmental impacts, while advancing economic growth.”
Katie Wilson, Mayor of Seattle, said:
“Seattle is working rapidly to ensure responsible data center policy, including a recent one-year data center moratorium that I am eager to sign after unanimous passage by City Council.
“I am proud to join my fellow mayors in signing the Global Urban Data Centres Pact and immediately getting to work on analysing how data centers impact Seattle’s electrical grid, water usage, utility rates, land use, local jobs, and public health, in partnership with industry partners, residents, and other global leaders.”
Cities need national governments and industry to act
More than 1,700 data centres are now operating in C40 cities, with more coming online each month
Data centres are now a core part of urban life, powering everything from public services to business growth. But without proper planning and clear standards, their expansion risks driving up energy demand, increasing costs and placing additional strain on infrastructure.
The Pact addresses this directly. But cities can’t deliver this alone; all levels of government and the private sector need to work with mayors to drive the development of urban data centres which meet these standards.
Cristina Gamboa, CEO of the World Green Building Council, said:
“The World Green Building Council and its network welcomes this bold signal from Mayors of C40 Cities.
“Data centres are not just buildings; they are major, long-term consumers of critical urban resources, and the decisions being made today about these AI factories will shape local energy systems, water supplies and communities for decades to come. By uniting behind a shared sustainability vision, C40 Cities are doing exactly what this challenge demands: ensuring data centres serve not just the global economy, but the communities and cities that host them.
“The WorldGBC stands ready to support this mayor-led momentum and continue to partner as we accelerate the shift toward resilient, regenerative data centre infrastructure fit for a sustainable digital future.”
Mark Watts, Executive Director of C40 Cities, said:
“Data centres have become one of the hottest topics in conversations between mayors around the world. The growth of AI and the digital economy is creating huge demand for new infrastructure, bringing opportunities for jobs and investment, but also real questions about energy use, water resources and community impacts.
“As the level of government closest to people, cities are uniquely placed to ensure this infrastructure is planned and operated in ways that benefit residents and protect the natural environments on which we all depend. The Global Urban Data Centres Pact shows that mayors are wasting little time in collaborating to shape the future of digital infrastructure in our cities.
“By working together, city leaders will move faster, learn from one another and establish practical approaches that maximise public benefits while minimising risks. The digital economy depends on cities. This Pact helps ensure cities and their residents benefit from it too.”
The launch comes at a critical moment. Global data centre capacity is expected to grow rapidly over the next decade, with much of that growth concentrated in cities. At the same time, cities are working to cut emissions, reduce exposure to extreme heat and ensure infrastructure keeps pace with population growth.
By creating an ambition loop between cities and industry, the Global Urban Data Centre Pact sets out a practical pathway for the sector’s growth that does not come at the expense of climate targets, natural resources, or energy prices, with no trade-offs between economic growth and quality of life.
Further endorsements are expected in the coming months, with additional cities encouraged to join the pact ahead of COP31.
Endorsing cities
The Global Urban Data Centres Pact founder signatories are:
- Abidjan, Côte d’Ivoire
- Ahmedabad, India
- Albuquerque, NM, USA
- Athens, Greece
- Austin, TX, USA
- Baakline, Lebanon
- Barcelona, Spain
- Beverly, MA, USA
- Boise, ID, USA
- Bologna, Italy
- Boston, MA, USA
- Chennai, India
- Chicago, IL, USA
- Cleveland, OH, USA
- Columbia, SC, USA
- Columbia, MO, USA
- Copenhagen, Denmark
- Curitiba, Brazil
- Freetown, Sierra Leone
- Heidelberg, Germany
- Johannesburg, South Africa
- Lincoln, NE, USA
- London, UK
- Madison, WI, USA
- Medellín, Colombia
- Melbourne, Australia
- Miami, FL, USA
- Milan, Italy
- Montreal, Canada
- Mumbai, India
- Nairobi, Kenya
- Oslo, Norway
- Palo Alto, CA, USA
- Phoenix, AZ, USA
- Portland, OR, USA
- Quezon City, Philippines
- Renca, Chile
- Rio de Janeiro, Brazil
- Riverside, CA, USA
- Seattle, WA, USA
- Sydney, Australia
- Tshwane, South Africa