Reductions have come - despite the cities growing - by using less fossil fuel, boosting public transport and cutting waste

By Sebastien Malo

SAN FRANCISCO, Sept 13 (Thomson Reuters Foundation) - More than two dozen of the world's largest cities are no longer increasing their planet-warming greenhouse gas emissions, they announced at a global climate summit in San Francisco.

The 27 cities, from New York to London, said they had reached the milestone even as their populations and economies grew.

They did so by cutting their usage of fossil-fuel-generated energy, growing their public transportation systems and reducing waste, according to C40 Cities, a network of large cities acting as leaders in combatting climate change.

Paris' Mayor Anne Hidalgo said it was a relief to "finally share good news on climate change."

With economies continuing to grow even as emissions stagnate or fall, "we can prove that we can also create jobs, create opportunities with the ecological transition," she told reporters.

Global warming is currently set to exceed the more ambitious limit of 1.5 degrees Celsius (2.7-degree Fahrenheit) called for in the 2015 Paris Agreement to curb climate change, according to a draft U.N. report due for publication in October.

Under President Donald Trump, the United States - the world's second largest greenhouse gas emitter - has weakened the Paris pact by announcing last year it intended to pull out of the deal.

MOVING ACTION SOUTH

So far, cities that have "peaked" their emissions are in industrialized nations in North America, Europe and Australia, research by C40 found.

Those cities are home to 54 million people, the group said.

The absence of developing world cities from the list suggests they may need more funding to make needed changes, Hidalgo told the Thomson Reuters Foundation.

"We must strive toward funds going toward the ecological and energy transition where it is most urgent, including in developing cities," she said.

Michael Burger, executive director of the Sabin Center for Climate Change Law at New York's Columbia University, said it was expected that poorer countries, many of them still growing, might still see emissions increases.

"It is a fact that countries are on different development pathways and so different cities are going to peak emissions ... at different times," he said.

PROTESTS

Demonstrations and stunts by activists also marked the summit, which aims to deepen the leadership of authorities other than national governments in curbing global warming.

Outside the gathering, about 300 protestors chanted slogans and brandished signs and banners reading "fossil free" and "don't drill".

Law enforcement officers made two arrests, said a San Francisco police spokeswoman.

Activists said in a statement they were targeting California Governor Jerry Brown - the summit's main organizer - for "his failure to rein in the state's oil extraction".

A handful of protesters also stormed the event's main stage as Michael Bloomberg, the former New York mayor and U.N. Special Envoy for Climate Action, delivered a speech.

"Climate capitalism is killing our communities," read a banner they unfurled before they were escorted out by security officials.

"Only in America could you have environmentalists protesting an environmental conference," Bloomberg quipped.

The three-day gathering, which ends Friday, has drawn about 4,500 delegates from city and regional governments worldwide as well as industries and research institutions.

It has also attracted celebrities, from actor Harrison Ford to primatologist Jane Goodall and musician Dave Matthew. (Reporting by Sebastien Malo @sebastienmalo, Editing by Laurie Goering

Our Standards: The Thomson Reuters Trust Principles.