Tens of thousands of students from more than 60 communities across the United Kingdom skipped class on Friday to join the global youth-led #schoolstrike4climate, calling on world leaders to take bolder steps to eradicate fossil fuels and combat the climate crisis.

"It's sort of scary to think about that when I'm older there might not be a North Pole or maybe no rainforest or anything."

—11-year-old striker

Speaking to Sky News in London's Parliament Square on Friday, 12-year-old Theo said he is striking "because there are people in that building over there, going in week in and week out, and completely declining the fact that our world is dying out."

Theo added that he thinks U.K. legislators, who are failing to take necessary steps to address the crisis, "are completely obsessed...with money" and "are completely disregarding...the world."

Pointing to rising temperatures and visible changes in the global climate, Theo's 11-year-old friend said he joined the strike because "it's sort of scary to think about that when I'm older there might not be a North Pole or maybe no rainforest or anything."

"I've come here to demand that the government address climate change as the crisis and the emergency that it is." Tens of thousands of children across the UK are striking against climate change Updates on the action live here: https://t.co/oyW08RWtnI pic.twitter.com/oaXlFFuK2M — Sky News (@SkyNews) February 15, 2019 'It's scary to think that when I'm older there might not be a North Pole or maybe a rainforest.' Students protesting in London say politicians are not taking enough action on climate change. Latest on #SchoolStrike4Climate here: https://t.co/qj2gtYAIAq pic.twitter.com/OVSGWuJiIb — Sky News (@SkyNews) February 15, 2019 Parliament Square in London is getting packed with young people demanding climate action - politicians better listen! #climatestrike #schoolstrike4climate pic.twitter.com/qGHBqQQn1l — Fossil Free UK (@FossilFree_UK) February 15, 2019

The striking students carried signs that warned "our generation will suffer," and asked, "the climate is changing, why aren't we?" Chants across the country ranged from "whose streets, our streets," and "we want change," to "fuck Theresa May"—the Tory prime minister who criticized the demonstrations via a spokesperson.

Our 6th #schoolstrike4climate was the biggest yet & we striked alongside thousands around the UK! I am striking not just for the climate but for nature, for wildlife & for the people on this planet. Change is coming. The young people of this world are standing up for our future pic.twitter.com/u9GiZ6ZICi — Holly Gillibrand (@HollyWildChild) February 15, 2019 Listen to the youth. We are the future. And we stand on the shoulders of generations of activists who have come before us. Solidarity to @Strike4Youth. #YouthStrike4Climate pic.twitter.com/sOq3QGmzPZ — Extinction Rebellion (@ExtinctionR) February 15, 2019 And yes, the chant is 'fuck Theresa May'. The kids are alright. SCROLL TO CONTINUE WITH CONTENT Never Miss a Beat. Get our best delivered to your inbox.





— Callum Cant (@CallumCant1) February 15, 2019

Some students spontaneously blocked Downing Street—which houses the prime minister's residence and office—and police even began arresting some strikers, according to posts on social media by the environmental group Extinction Rebellion and other observers:

Endorsed by the National Association of Head Teachers as well as Labour Party Leader Jeremy Corbyn, the U.K. climate strike follows several recent mass mobilizations of young people across the globe.

"I've always had a strong fascination with the environment, and I've always been aware of climate change and sustainable living, but when I saw thousands of kids around the world striking for the cause it inspired me to start my own," 17-year-old Anna Taylor, a co-founder of the U.K. Student Climate Network, the group coordinating the country's strike, told the New York Times.

"Youth voices are too often left out of the discussion when it comes to climate change."

—Jake Woodier, U.K. Youth Climate Coalition

"While we're failing to deliver the changes young people need, we can hardly blame them for taking action themselves. Education has today been flipped on its head. The young are teaching the old, and we should pay attention," Greenpeace U.K. executive director John Sauven said in a statement to the Guardian.

"Young people know that their lives are going to be changed dramatically by the impacts of climate change. The risks that older people hope they might dodge are the problems the young will inherit," Sauven added. "And the longer the young wait for action to be taken, the harder it will be for them in future."

Jake Woodier, a member of the U.K. Youth Climate Coalition, noted that "youth voices are too often left out of the discussion when it comes to climate change." As he told the Times, "Our current trajectory is completely incompatible with a clean, safe environment not only for ourselves, but future generations as well."

That sentiment was echoed by Greta Thunberg—a 16-year-old from Sweden whose protests outside her country's parliament last year inspired the global movement—who discussed the U.K. demonstrations on "Good Morning Britain" Friday:

16-year-old Swedish schoolgirl Greta Thunberg, who started the climate strike at her school last year, tells us what inspired her to start the movement.#schoolstrike4climate | #ClimateStrike | #GMB pic.twitter.com/Ag4tp38rJl — Good Morning Britain (@GMB) February 15, 2019

As Thunberg put it, "Why should we be studying for a future that soon might not exist anymore?"