NEW YORK — In one of a series of events held around the globe to raise awareness about climate change, tens of thousands of activists walked through Manhattan on Sunday, warning that climate change is destroying the Earth — in stride with demonstrators worldwide who urged policymakers to take quick action.
In Seattle, hundreds of people turned out for an afternoon rally at Westlake Park.
Celebrities like actor Mark Ruffalo and actress Evangeline Lilly were joined in midtown Manhattan by United Nations Secretary-General Ban Ki-moon, former Vice President Al Gore and New York City Mayor Bill de Blasio.
Organizers, using data provided by 35 crowd spotters and analyzed by a Carnegie Mellon University mathematician, estimated that 311,000 people marched in New York.
On Tuesday, more than 120 world leaders will convene for the United Nations Climate Summit aimed at galvanizing political will for a new global treaty by the end of 2015.
“My sense is the energy you see on the streets, the numbers that have amassed here and in other cities around the world, show that something bigger is going on, and this U.N. summit will be one of the ones where we look back and say it was a difference maker,” de Blasio said.
“Climate change is a defining issue of our time, and there is no time to lose,” he said. “There is no Plan B because we do not have planet B. We have to work and galvanize our action.”
In New York, a contingent came from Moore, Okla., where a massive tornado killed 24 people last year, as did hundreds of people affected by Superstorm Sandy, which the U.S. National Oceanic and Atmospheric Administration and the British meteorological office said was made more likely by climate change.
In London, organizers said 40,000 marchers participated, while a small gathering in Cairo, Egypt, featured a huge art piece representing wind and solar energy.
In Rio de Janeiro, marchers at Ipanema Beach had green hearts painted on their faces.
Celebrities in London including actress Emma Thompson and musician Peter Gabriel joined thousands crossing the capital’s center, chanting: “What do we want? Clean energy. When do we want it? Now.”
“This is important for every single person on the planet, which is why it has to be the greatest grass-roots movement of all time,” Thompson said. “This is the battle of our lives. We’re fighting for our children.”
In Australia, the largest rally was in Melbourne, where an estimated 10,000 people took to the streets with banners and placards calling on their government to do more to combat global warming.
Australian Prime Minister Tony Abbott was a particular target of the protesters. Abbott’s center-right coalition has removed a carbon tax and has restricted funding for climate-change bodies since coming to power last year.
The coalition of groups that organized the event is calling for a rapid shift away from fossil fuels, and a massive expansion of clean energy.
In Seattle, Ross Macfarlane, a senior adviser at Climate Solutions, said he spoke about the need to reach a social and political tipping point that will create enough pressure to prompt action on climate change. “That’s what the global day of action is all about,” said Macfarlane.
Other rallies were held this weekend around the Pacific Northwest, including one Saturday at the Peace Arch Park north of Bellingham that brought together people from the U.S. and Canada.
Others scheduled Sunday included rallies in Spokane, Walla Walla, Puyallup, Pullman and Longview, where several dozen people gathered at the city’s Lake Sacajawea Park. There, for 350 seconds, they clashed garbage-can lids, rang Tibetan bells and made other noise to show support for the New York march.
“It was kind of registering that here in Longview, we want change, too,” said the Rev. Kathleen Patton, an organizer of the event.
In New York, The People’s Climate March, organized by a dozen environmental, labor and social-justice groups, was a spectacle even for a city known for doing things big.
At one point, the march came to a halt because the entire 2.2-mile route was full, and more than two hours into the procession, people were still setting out from the starting point near Columbus Circle.
The climax of the march came in the early afternoon. All along the route, crowds had been quieted for a moment of silence. On Avenue of the Americas at 57th Street, there was an eerie silence as marchers raised their arms and looked down.
Then at exactly 1 p.m., a whistle pierced the silence, setting off a minutelong cacophony intended as a collective alarm on climate change.
There were the beats of the drums and the blaring of horns, but mostly it was whoops and cries of the marchers.
One of the key organizers of the event, the international advocacy group Avaaz, presented a petition with more than 2.1 million signatures demanding action on climate change.
“It’s a testament to how powerful this movement is,” said Ricken Patel, executive director of Avaaz. “People are coming in amazing numbers.”
Like the march, the summit meeting Tuesday at the United Nations will be flush with speeches intended to build support for addressing climate change.
But the gathering of world leaders is not meant to be a formal negotiating session for a potential 2015 agreement.
A few blocks from the march, in a hotel conference room on Lexington Avenue, Secretary of State John Kerry convened a meeting of foreign ministers of the 17-member Major Economies Forum, focused on climate change. Todd Stern, the chief United States climate-change negotiator, held back-to-back meetings throughout the day.
Kerry said he intended to keep a focus on climate change throughout the week, despite the pressure of other crises, including insurgent terrorists in Iraq and the Ebola outbreak in Africa.
Global emissions of greenhouse gases jumped 2.3 percent in 2013 to record levels, scientists reported Sunday, in the latest indication that the world remains far off track in its efforts to control global warming.
The emissions growth last year was a bit slower than the average growth rate of 2.5 percent during the past decade, and much of the dip was caused by an economic slowdown in China, the world’s single largest source of emissions.
It may take an additional year or two to know if China has turned a corner toward slower emissions growth, or if the runaway pace of recent years will resume.
In the United States, emissions rose 2.9 percent after declining in recent years, said the tracking initiative called the Global Carbon Project, which published its findings in the journal Nature Geoscience.
In another development, the family of John D. Rockefeller, whose legendary wealth flowed from Standard Oil, plans to announce Monday that its $860 million philanthropic organization, the Rockefeller Brothers Fund, is joining the movement that began a couple of years ago on college campuses to divest in fossil fuels.
In recent years, 180 institutions — including philanthropies, religious organizations, pension funds and local governments — as well as hundreds of wealthy individual investors have pledged to sell assets tied to fossil-fuel companies from their portfolios and to invest in cleaner alternatives.
Compiled from The New York Times and The Associated Press, and including material from Seattle Times staff reporter Hal Bernton.