Leading British cities have signed up to a pledge to run entirely on green energy by 2050 as local governments push for accelerated change ahead of next week's UN climate change summit in Paris.

Councils run by the opposition Labour Party including Manchester, Liverpool, Edinburgh and many London boroughs have vowed to become "100 percent clean" before 2050, in line with the commitments to be made nationally and internationally at the Paris summit.

"We hope other towns and cities across the globe will join us to demonstrate that this transition will happen through acts of leadership by the many, not the few," said the pledge, coordinated by Lisa Nandy, Labour's top official on energy and climate change.

The commitment will mean renewable energy-powered transport, an end to gas heating in official buildings and a programme of mass insulation of homes.

Other cities involved include Leeds, Newcastle, Glasgow and Sheffield.

"This pledge shows that towns and cities across Britain are prepared to... show leadership in the run up to the Paris Climate Change talks," Nandy told AFP on Tuesday.

"City leaders around the world are already showing how it is possible to make urban areas safer, cleaner places to live while dramatically reducing emissions of greenhouse gas pollution."

If met, the pledge would help reduce Britain's carbon emissions by 10 percent, and if adopted by cities globally could "deliver cuts in carbon pollution on par with the annual output of a large economy like India," Nandy said.

- Urgency 'greater than ever' -

The C40 Cities Climate Leadership Group (C40) -- a network of global cities taking action to reduce emissions -- on Monday said that action by the world's largest cities had "forged a pathway to low-carbon and climate-resilient development."

The C40 study cited projects including installing energy-efficient LED streetlights, building bus rapid transit lines and financing waste-to-energy projects.

"Global urban policy decisions before 2020 could determine up to a third of the remaining global carbon budget that is not already 'locked-in' by past decisions," it said.

"The urgency to act is greater than ever."

C40 chairman and Rio de Janeiro mayor Eduardo Paes said that cities could "provide hope to the world and a backbone to the climate negotiators assembling in Paris this month."

UN special envoy for cities and climate change and former New York mayor Michael Bloomberg said that the "C40 cities have helped lead the way".

Some 147 heads of state and government are due in Paris next week for a 12-day summit to forge a climate pact tasked with keeping Earth liveable for humanity.

After six years of preparatory negotiations, the 195 nations gathering under the UN flag remain sharply divided on how to tackle the issue.