The UN chief made the call in a message issued marking the World Cities Day (October 31) that comes at the end of “Urban October”, a month dedicated to raising awareness on urban challenges, successes and sustainability.

Guterres said more than half the world’s population now lives in urban areas and by 2050, two-thirds will do so.

“Much of what will be needed to house and serve this increasingly urban world has yet to be constructed, and even some new cities will need to be built,” he said.

This brings enormous opportunities to develop and implement solutions that can address the climate crisis and pave the way towards a sustainable future, the UN chief added.

Guterres cities consume more than two-thirds of the world’s energy, and account for more than 70 percent of global carbon dioxide emissions.

He said the choices that will be made on urban infrastructure in the coming decades – on urban planning, energy efficiency, power generation and transport – will have decisive influence on the emissions curve. Indeed, cities are where the climate battle will largely be won or lost.

“But in addition to their enormous climate footprint, cities generate more than 80 percent of global gross domestic product and, as centers of education and entrepreneurship, they’re hubs of innovations and creativity, with young people often taking the lead,” Guterres said.

The UN chief said from electric public transport to renewable energy and better waste management, many of the answers needed for the transition to a sustainable, low-emission future are already available. Cities around the world are turning them into a reality. 

“It’s encouraging to see this happening, but we need this vision to become the new norm. Now is the time for ambitious action,” he said.