This article originally appeared in BUILDER magazine.

Mayors of 19 major global cities, including eight cities in the U.S., have signed the Net Zero Carbon Buildings Declaration ahead of the upcoming Global Climate Action Summit, Sept. 12–14, in San Francisco. By signing the declaration, the mayors have pledged to ensure that all new buildings in their cities operate at net-zero carbon by 2030 and that all buildings, old or new, meet net-zero carbon standards by 2050.

The declaration was created through C40 Cities, which represents the ongoing commitment of 96 global cities and more than 700 million citizens to the “highest goals” of the Paris Agreement, including the reduction of global warming to under 1.5 degrees C (34.7 degrees F). According to C40 estimates, urban buildings can account for up to 70% of a city’s total emissions and over half a million people die each year due to outdoor pollutant exposure.

The U.S. signatories are the mayors of New York City; Portland, Ore.; Los Angeles, San Francisco, San Jose, and Santa Monica, Calif.; Washington, D.C.; and Newburyport, Mass. The global signatories include the mayors of Toronto, Vancouver, and Montreal, Canada; Paris; London; Sydney, Australia; Tokyo; Stockholm, Sweden; Copenhagen, Denmark; and Johannesburg and Tshwane, South Africa.

“Climate change poses an existential threat to New York City, and making our buildings more sustainable and efficient is a key part of the solution,” said Bill de Blasio, mayor of New York City, in a statement. “With this commitment, we’re delivering on our promise to make New York City cleaner and safer for generations to come by meeting the Paris Agreement. We’re proud to stand alongside other cities worldwide that are taking bold and meaningful steps to cut the pollution driving climate change.”

In order to achieve these goals, each city pledged to establish a road map toward net-zero carbon implementation, develop construction incentives and programs, and report annually on their progress toward these targets. While city governments don't have direct control over all buildings in a city, the Declaration includes a pledge to work with state and regional governments, as well as the private sector, to enact change. It also calls on federal and national governments to take the same or similar actions.

Thirteen cities—including Portland, San Jose, Santa Monica, and Newburyport—have made an additional commitment to own, develop, and occupy only net-zero carbon assets by 2030. They will evaluate the current energy demand and usage levels at their municipal buildings, create a road map toward reduction, and make additional annual reports.

“Paris is home to some of the world’s most beautiful and iconic buildings. 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 Anne Hidalgo, mayor of Paris and chair of C40. “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.”