Phoenix Mayor Kate Gallego says a global push to rein in the environmental costs of data centers has gained support since she helped launch it earlier this year, with more than 50 mayors now having joined the effort. Gallego announced the milestone Tuesday, framing it as evidence that Phoenix, a city confronting the growth of data centers, is shaping the conversation rather than just absorbing its consequences.
“I’m proud to be a voice on the global front—working with the Mayor of Melbourne, Australia, to launch the Urban Data Center Pact earlier this year. More than 50 mayors have now joined our efforts,” Mayor Kate Gallego
wrote. The pact she referenced, formally called the Global Urban Data Centres Pact, debuted at London Climate Action Week in June, according to
C40 Cities
, the international network of mayors that organized the effort.
C40 described the pact's founding signatories as 41 cities spanning six continents and representing more than 90 million people, while other coverage at the time, including a report from RTÉ, put the number at 40 cities preparing to sign. The pact later reached 49 endorsing cities, while Gallego said more than 50 mayors had joined the effort. C40's own materials describe the pact as a “mayoral-led vision that sets the conditions for sustainable urban data centres,” aiming to guide the industry's growth without sacrificing climate goals, water supplies, or affordable energy prices.
Why Phoenix Signed On
Gallego has cast Phoenix's involvement as a direct response to what the city is already living through. “Phoenix has experienced first-hand the significant expansion of AI and digital economy infrastructure,” she said, according to C40's report on the pact's launch. Melbourne Lord Mayor Nicholas Reece echoed that framing, saying, “We’re proud to work alongside Phoenix and dozens of cities around the world to develop the Global Urban Data Centres Pact,” per the same C40 account.
The stakes for Phoenix are concrete. The metro area now has 225 existing or planned data centers, with proposals on the table that could double local electricity demand, according to Data Center Dynamics.
A Global Resource Squeeze
The pact's underlying concern is the scale of data-center growth and its demands on urban resources. Cities are weighing how to accommodate digital infrastructure while protecting climate goals, water supplies and affordable energy. Because facilities can be concentrated in particular locations, their electricity needs can put pressure on local grids.
Water is under similar strain. As artificial-intelligence use expands, data centers place demands on electricity and water. C40 separately estimates that the combined data-center and network ecosystem accounts for 2.5 to 3.7 percent of global greenhouse gas emissions.
What the Pact Asks Of Cities and Companies
The Global Urban Data Centres Pact calls for facilities that are strategically integrated into cities, resource-efficient, engaged with local communities, and focused on shared prosperity, according to C40's project materials. It is intended to guide planning, permitting and negotiations around future development. Melbourne, where roughly 50 major data centers already operate, expects the facilities to account for about 10 percent of local power demand by 2030 and as much as 20 percent by 2040, per RTÉ.
Not every city has taken the collaborative route. Seattle's City Council voted unanimously to adopt an emergency data-center moratorium and a policy framework intended to help prevent large facilities from siting in the city, according to a statement from the Seattle City Council. Gallego's post did not address whether Phoenix is weighing similar restrictions, and it remains unclear which specific cities have joined the pact's ranks since its June debut.
