Montreal, Toronto, and Vancouver are three of 19 cities around the world whose mayors have promised to ensure that all new buildings in their communities are net-zero carbon by 2030—and that all their cities’ buildings, old and new, meet a net-zero standard by 2050.

The mayors made their announcement ahead of the Global Climate Action Summit coming up in San Francisco next month. The full list of participating cities, with a combined population of 130 million, includes Copenhagen, Johannesburg, London, Los Angeles, Montreal, New York City, Newburyport, Paris, Portland, San Francisco, San José, Santa Monica, Stockholm, Sydney, Tokyo, Toronto, Tshwane, Vancouver, and Washington, D.C.

“As mayors of the world’s great cities, we recognize our responsibility to ensure every building, whether historic or brand new, helps deliver a sustainable future for our citizens,” said C40 Cities Chair and Paris Mayor Anne Hidalgo. “With this commitment cities are getting the job done, concretely delivering on the Paris Agreement, and building better cities for generations to come. One more time, the future is taking place in cities.”

“Cities across the world must accelerate the reduction of greenhouse gas emissions to avoid the worst impacts of global climate change,” said San Francisco Mayor London Breed. “San Francisco’s commitment to green building design has produced some of the most energy- and resource-efficient buildings in the world. Shifting away from fossil fuels and powering our buildings with 100% renewable energy will further our commitment to addressing climate change.”

“We are excited to be signing the C40 Net Zero Carbon Emissions Declaration along with other major cities around the world,” said Vancouver Mayor Gregor Robertson. “Vancouver’s Zero Emission Building Plan will not only reduce GHG emissions from new buildings by over 60% but is also driving our green economy, with a 53% increase in green building jobs since 2010.”

In its release, C40 Cities notes that buildings generally account for more than half of a city’s greenhouse gas emissions—and that outdoor air pollution due to building energy use causes a half-million premature deaths per year.

But “delivering on the commitments made today will require a united effort, as city governments do not have direct control over all the buildings in a city,” the organization states. “This commitment includes a pledge to work together with state and regional governments and the private sector to drive this transformation, and calls on national governments for equal action.”

To translate their promises into results, the cities committed to develop net-zero roadmaps, introduce a “suite of supporting incentives and programs”, report their progress annually, and evaluate whether to report on other forms of emissions, like refrigerants.

Montreal, Toronto, and Vancouver were also among a smaller group of 13 communities that committed to “owning, occupying, and developing only assets that are net-zero carbon by 2030,” C40 notes.