Students in New York City joined others around the world in a coordinated school strike Friday, walking out of class to demand action on climate change. There were more than four hundred such strike actions in the United States alone and at least 1,600 worldwide, in more than one hundred countries.

When I meet Alaisha Negron, sixteen, in Lower Manhattan, she was on her way to City Hall where she and other striking kids were gathering. “This is all going to be flooded!” she was shouting to the handful passersby. “We’re going to be under water. Do you want that?”

Although the New York City government — not to mention the national government — could be doing much more to address the problem, it is getting one thing right: some of our public schools are nourishing the engaged and informed citizenry that this crisis needs.

Negron, along with Shemiah Neckles and Sanaa Wells, both 16, are students at the Urban Assembly Institute of Math and Science for Young Women.

“Climate change is a big thing at our school,” adds Shemiah Neckles, explaining that they grow aquatic plants, including lettuce and cucumber, and use no bottled water.

“Some people don’t know what climate change is or don’t think it’s a problem,” said Wells. “Going to a math and science school helps you to be more aware and more conscious of the things that are happening around you.” It’s a responsibility, too, she acknowledges, “We have to stand up for the people who don’t know and don’t care.”

Negron learned about the threat of climate crisis in her environmental science class. “I cried,” she remembers. “I literally cried. I had to walk out of the class. It was so heartbreaking.”

She walked out of class again Friday, this time with solidarity from all over the world.

The US Youth Climate strikers were demanding a Green New Deal; an immediate halt to all fossil fuel infrastructure projects, including pipelines; preservation of public lands; a requirement that all policy decisions be grounded in scientific research; and that climate change be declared a national emergency — and compulsory K-12 education on climate change.

In front of City Hall, there were thousands of kids, as well as some parents and teachers. One sign, marked “12 Years Left,” referred to the 2018 report by the United Nations Intergovernmental Panel on Climate Change (IPCC), which warned of irreversible consequences unless decisive action is taken to ease global warming within twelve years.

Amna Younis, fifteen, a student at Millenium Brooklyn High School, added, “In the future the world could be no more, if no one takes action now.”

Chinyere Meremetoh, eighteen, a student at the High School for Environmental Studies in Midtown, held a sign recognizing Greta Thunberg, the sixteen-year-old Swedish girl who has become a worldwide leader in the climate movement. Thunberg’s activism started with a weekly solo Friday school strike, and she has inspired kids in Sweden and around the world to do the same.

Like the Urban Assembly students, Meremetoh and her schoolmates credit their school with their engagement on this issue. Melanie Mueses, eighteen, said, “The school really pushed me to understand how the environment is crumbling and how we are affecting it,” she says. “I wasn’t like that before.” Meremetoh tells me about an art project she did, showing the sun going from cold to warm to hot. “A lot of people don’t pay attention, and don’t realize the world could be ending in a couple years.”

Mueses suspects policymakers don’t care since they think they’ll be dead when problems caused by climate change get more serious. “I feel people in power don’t feel as deeply about this as us because they’re not going to be here,” she explains. “Us, as ‘the future,’ we are the ones who are going to be most affected.”

Emmanuel Pimentel, eighteen, also a student at High School for Environmental Studies agreed: “We need the world.”

Said Meremetoh, “We have to stand up to everything Trump is saying because he’s crazy. We have to continue to fight. We can’t stop.” Asked what she hopes comes out of these actions, she says, “I hope the future president listens. We have to start taking care of the environment. I really hope the government listens to us, the young people.”

Climate strikers at City Hall were mostly high school kids, but there were younger children, too. A growing movement, #Fridays4Future will continue the Friday strikes that Greta Thunberg began.