NEW YORK — Millions of young people took to the world’s cities Friday, flooding streets, blocking traffic and skipping school to take part in what is believed to be the biggest global climate protest in history.

The Youth Climate Strike drew potentially record crowds in several cities. In Australia, nearly 200,000 people protested in Melbourne and Sydney. Hundreds of thousands more—in Islamabad, Nairobi, Berlin, London, La Paz, New York, and as many as 1,500 other cities on every continent—joined in a global plea for elected leaders and governments to take action on the climate crisis.

It was “even bigger than we dared dream,” said Bill McKibben, environmentalist, author and founder of 350.org, which helped organize some of Friday’s protests. “At a minimum, 5 million people were out around the planet to show their determination to bend the curve of history. A remarkable day.”

In New York City, organizers estimated a quarter million protesters joined rallies and marched through the financial district toward Battery Park. Chants of “Hey, hey. Ho, ho. Fossil fuels have got to go,” rang through the concrete canyons, along with: “Wall Street, we see your greed.”

“We are a new generation, and we are the last generation … that can stop a climate disaster,” 17-year-old Grace Goldstein told the crowd at a rally before the march.

Other speakers at the New York rally talked about the damage caused by fossil fuels and how marginalized communities—like those recovering from devastating hurricanes in the Bahamas and Puerto Rico—will bear the brunt of climate change.

NYCs massive #ClimateStrike march has begun, from Foley Sq down Centre St to Chambers St across to Broadway… and down to the Battery! Thank you @ClimateCrisis and everyone else marching! pic.twitter.com/WUpeRP0ZQS

— Gale A. Brewer (@galeabrewer) September 20, 2019

The group Young Evangelicals for Climate Action held demonstrations at about a dozen colleges and universities, stressing that protecting God’s creation and speaking up for people’s right to clean air and water and a stable climate is part of living their faith.

The damage from extreme weather events, particularly the kinds that scientists warn will only worsen as global temperatures rise, is growing more evident around the world.

As the strikers were hitting the streets, parts of coastal Texas were reeling from flooding left by Tropical Storm Imelda, now one of the wettest tropical storms on record to hit the Lower 48 states, not far behind 2017’s Hurricane Harvey. Off the U.S. Pacific Coast, a potentially devastating marine heat wave was taking shape, increasing the risks to sea life, as well as risks for hurricanes in Hawaii and wildfires in California. Large swaths of the Midwest flooded in the spring, and the Arctic saw widespread wildfires through the summer and record melting on the Greenland Ice Sheet.

The coordinated strike was timed ahead of the United Nations Climate Summit in New York, where countries are expected to enhance their commitments to reducing greenhouse gases under the Paris climate agreement. Another strike is scheduled for next Friday.

The protests come a year after teenager Greta Thunberg sat alone outside the Swedish Parliament with a handmade sign, imploring the government to take action on climate change. Thunberg’s solo protest grew into a global youth movement, culminating in Friday’s events and capping off a week in which Thunberg testified before Congress and was preparing to speak before the UN Climate Summit.

“I think it will make it ever clearer to our leaders that their ability to delay is just about finished,” McKibben said of Friday’s events. “People are fed up, scared, and also hopeful that we can build a new world. Those who get in the way from this point will do it at their political peril.”

Here, some dispatches from around the U.S., from InsideClimate News reporters:

San Diego, California

First came the rallying cry to fire up the students at Eastlake High School in Chula Vista, Calif., just south of San Diego.

“Climate change is not a lie. Do not let our planet die.”

Then came the stream of unambiguous messages from the students at the microphone.

 “I am angry that the generation in power has denied climate change,” said demonstration organizer and 16-year-old senior Sonya Googins, She spoke to a crowd of students who left class to raise their voices in the school’s outdoor plaza.

“It is real. It is a threat to the world. It is time to do something.”

The Eastlake students want to see action now—policies, philosophy and action that will begin to turn the tide.

“If we don’t think about this moment right here, right now, there might not even be a future,” said 14-year-old freshman MacKenzie Tarde.

There was no mistaking the determination and wisdom of the hundreds of Eastlake students who participated.

“We have been given the leftovers of an irreplaceable planet that is beautiful and astounding and will never see the tomorrows to come if we don’t act and let our voices be heard,” said Jessica Garcia, a 14-year-old freshman.

—David Hasemyer

Portland, Maine

Hundreds of students led the crowd in a chant on the steps of Portland City Hall in Maine: “We believe Bill Nye, climate change is not a lie!”

The students, ranging from elementary to college age, baked under sunny skies and temperatures about 10 degrees above normal for a September afternoon.

Teachers from local high schools led large groups of sign-wielding students. Many schools in the area had given permission for kids to skip class in order to attend the rally.

Molly Wendell-Pearson and Devyn Shaughnessy, 15-year-old sophomores from Casco Bay High School, started the morning at Devyn’s house, making signs. “We don’t need opinions on facts,” Wendell-Pearson wrote on one. 

More than 2,000 people attended the strike, one of several planned across the state. 

“They should have acted before,” said 10-year-old Thea Dugas, a fifth grader at Portland’s Reiche Elementary School. “Now my generation has to fix it.”

—Sabrina Shankman

Boston

Thousands of people gathered at Boston’s City Hall Plaza, where climate policy stars Gina McCarthy, former head of the U.S. Environmental Protection Agency, spoke, and Sen. Ed Markey (D-Mass.), co-sponsor of the Green New Deal, was spotted in the crowd. But it was the leaders of the youth movement who stole the show.

Eighteen-year-old Jeremy Ornstein of the Sunrise Movement gave an impassioned speech for urgent action that drew parallels to the civil rights movement and his grandmother’s fight for survival during the Holocaust.

“I know our ancestors are here right now standing with us. We are not alone,” Ornstein said. “We hold a weight on our back, but we hold it together, and that is how we are going to win.”

Ahria Ilyas, a member of Youth-On-Board and a freshman at Suffolk University, spoke of issues of environmental justice magnified by climate change.

“I am a woman of color in a world and neighborhood of homes that has been and will continue to be impacted by climate change, intolerable temperatures, destructive hurricanes and storms,” Ilyas said. “Listen to the people struggling. Stop ignoring the problems, address them head on and push for the Green New Deal.”

—Phil McKenna

Washington, D.C.

A crowd of thousands gathered at the foot of the U.S. Capitol building with a prevailing message: This is urgent.

“We have a lot to do,” said Malia Weinmann, a 12-year-old middle school student. “And we’ve got to get started.” Her sign read, “If you did your job, we’d be in school,” capturing another central message of the day: Lawmakers are failing to tackle this crisis.

With congressional committees holding hearings in buildings nearby, activists took to a stage overlooking the National Mall, imploring elected leaders to take action.

“We want you all … Congress, to look us in the eyes and tell us you’re going to do something,” said Nina Berglund, an activist from Minnesota. “You’ve had your time to talk. Now is our time. … This is nothing to be debated about.”

—Georgina Gustin

Louisville, Kentucky

In Louisville, 15-year-old twins Sophia and Isabella Blickenstaff had a message for Sen. Mitch McConnell (R-Ky.), the powerful U.S. Senate Majority Leader who has dismissed the urgency of the climate crisis.

“Listen to the young people,” Sophia said. “They know what they are talking about.”

The twins were among hundreds of students and adults who showed up at the morning rally in downtown Louisville that was punctuated by periodic downpours.

They finished each other’s sentences, and when asked how they felt the older generations had handled the climate threat, Sophia started off: “If there had been action earlier …,” then Isabella added: “It wouldn’t be as big of an emergency.”

“So yeah, I’m a little frustrated,” said Sophia, completing the thought.

Their grandmother, Diane Mueller of Columbus, Ohio, beamed with pride beside them. “This is democracy in action,” she said. “It’s just as important as any lesson in school today.”

—James Bruggers

Columbus, Ohio

It began with a group of schoolchildren from Red Oak Community School singing verses from what has become the anthem of the climate school strike movement.

“This is an S.O.S. from the kids.

Will the grownups take note of this?

We’re finding our voice, calling you out.”

Hundreds of students filled the steps of the Ohio Statehouse in Columbus. They spoke of their frustration that Ohio has not yet taken significant action to address climate change. This summer, the governor signed a measure that subsidizes coal-fired power plants and repeals requirements that utilities invest in renewable energy.

“We’re coming out to strike, letting people know that when they’re doing stuff we don’t like, we’re not going to stand for it,” said Addie Dodge, 17, a student at a nearby Columbus Academy.

Her sign read: “If You Won’t Act Like Adults, We Will!”

—Dan Gearino

Salt Lake City, Utah

Hundreds of Utahns carried umbrellas along with their posters for a rally at the historic City County Building in Utah’s capital. Teens led chants, including “This is what democracy looks like,” and “Corporate greed we must fight; corporate greed is not alright.”

Signature-gatherers joined Friday’s events in a campaign to amass more than 116,000 signatures to put climate pricing on the 2020 state ballot. If voters approve the measure, it would raise an estimated $100 million a year through a $12 tax on each metric ton of carbon dioxide emitted in the state.

Kate Nichols, Brenna Utley and Madeline Wimmer skipped a day of high school senior classes to join what they see as a history-making event.

“It shows that our future generation cares,” said Utley, “that we know what’s going on.”

“I want to be here longer,” said Wimmer, concerned that people will go the way of the dinosaurs because of the changing climate. “I want to have a family, and I want them to enjoy this.”

The three said the climate strike might be a sign that real change has begun. Nichols added: “At least I hope so.”

—Judy Fahys