No 'Plan B' for fighting climate change: UN chief

UN Secretary-General Ban Ki-moon said Sunday said there is no "Plan B" for fighting climate change, urging global efforts to galvanize action.

"This is the planet where our subsequent generations will live...There is no 'Plan B,' because we do not have 'Planet B,'" Ban told reporters after walking with an estimated 300,000 demonstrators in the People's Climate March through New York City.

The world needs to "galvanize our action" and harness the people's "power to change," Ban said.

The UN chief, wearing a T-shirt that read "I'm for climate action," walked nine blocks in the parade with US Former Vice President Al Gore, New York Mayor Bill de Blasio and French Ecology Minister Segolene Royal.

The march is believed to be the largest ever in the United States demanding measures to halt the advance of global climate change.

Outside New York, from London to Bogota, another 270,000 people turned out at about 2,500 events around the world, organizers said.

The event took place two days before Ban opens the much-anticipated Climate Summit at UN Headquarters in New York, which will draw more than 120 heads of state or government.

The summit is expected to set the stage for a crucial conference in Paris in December 2015 aimed at finalizing a new global climate change pact.

Politicians including US senators, actors such as Leonardo DiCaprio and Evangeline Lilly, as well as activists and the general public marched though the city to highlight global concerns about the lack of international action to stop the worsening effects of climate change.

Marchers, chanting slogans or playing music, created a noisy carnival atmosphere as they filed through Manhattan's West Side. Some were dressed in costumes associated with indigenous groups, others wore protest T-shirts. One banner in the shape of a road sign warned "Climate Crisis Ahead."

Twelve-year-old Marija Borozan from New York City was on her first ever protest march. "The world matters," she said.

"I want to save the environment," she told a reporter from UN Radio.

Ricken Patel, executive director of activist group Avaaz, which organized the march, said it was crucial for people to get out onto the streets.

"It's important because there's a huge gap between the action our survival requires...and the action our governments are willing to take" on climate change, he said. "The street is where we close that gap."

The People's Climate March is campaigning, among other issues, for curbs on harmful carbon emissions which contribute to global warming.

Ban said he hoped what people were saying in the march will be "truly reflected to the leaders" when they meet two days from now.

"Climate change is a defining issue of our times," he said. "There is no time to lose. If we do not take action now, we will have to pay much more."