“Existential threat”: 19 cities pledge all new buildings to be carbon neutral by 2050

Mayors of 19 cities including London, Los Angeles and New York have signed the "Net Zero Carbon Buildings Declaration", pledging that all new buildings will meet net-zero carbon standards by 2050.

Net-zero buildings use energy efficiently and meet any remaining energy needs from renewable sources.

The 19 cities signed up to the initiative are: Copenhagen, Johannesburg, London, Los Angeles, Montreal, New York City, Newburyport, Paris, Portland, San Francisco, San Jose, Santa Monica, Stockholm, Sydney, Tokyo, Toronto, Tshwane, Vancouver and Washington, DC.

Buildings in urban areas are one of the largest sources of greenhouse gas emissions, and typically account for over half of a total city’s emissions.

They may also be deadly: the International Institute for Applied Systems Analysis estimates that 500,000 people prematurely die each year due to outdoor air pollution caused by energy used in buildings.

Cities will have to work with state and local governments as well as the private sector to deliver net-zero goals, as city governments do not have direct control over all city buildings.

Under the initiative cities will:

• Create a roadmap to reach net-zero carbon standards by 2050;
• Develop incentives and programmes;
• Report annually on progress towards targets.

Bill de Blasio, New York City mayor, said: "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.

"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."

Image: Toronto Harbour: Toronto is one of the signatories (Wikimedia Commons/John Vetterli)