Swedish teenage climate activist Greta Thunberg may be best known for leading schoolchildren on weekly strikes across Europe, but adults are also getting swept up in the action.

From political leaders to activists to former corporate executives, adults are pledging support for Thunberg’s “Fridays for Future” youth movement, which is organizing a “Global Strike for Future” on March 15.

Since August, Thunberg, now 16, has skipped school on Fridays to draw attention to government inaction on climate change. In December, she gained international prominence during a speech at the U.N. Climate Change Conference in Poland in which she called on others around the world to join her.

“Many people say that Sweden is just a small country and it doesn’t matter what we do,” Thunberg said in the speech. “But I’ve learned you are never too small to make a difference. And if a few children can get headlines all over the world just by not going to school, then imagine what we could all do together if we really wanted to. But to do that, we have to speak clearly, no matter how uncomfortable that may be.”

Thunberg helped inspire Sarah Marder—who spent 22 years in corporate affairs at Citigroup before transitioning into environmental activism and nonprofit communications—to organize the Fridays for Future strike in Milan, Italy.

“It was like I had been called to join the team,” Marder told Bloomberg Environment.

Fridays, and More Fridays

Janine O’Keeffe, a climate activist who has worked with Thunberg in Stockholm, said the first thing that struck her about the teen was that she was leading a “strike” as opposed to just a protest.

She decided she wanted to meet Thunberg, and went to introduce herself and record a radio interview. She was so impressed that she came back seven times over the next two weeks.

At the time, Thunberg had planned a three-week strike leading up to the Swedish elections, but she hadn’t decided what—if anything—would come next. On Sept. 7, the teen announced the strikes would continue weekly even after the elections.

“I decided, ‘Okay, I will do whatever I can to support Greta,’” O’Keeffe said. Soon she was providing resources and assistance to groups trying to organize strikes in other countries.

Both Marder and O’Keeffe agreed the weekly format was crucial to building momentum and allowing the strikes to grow naturally.

The weekly strikes have spread to dozens of European cities, and so far, 1,325 strikes have been organized in 98 countries for the March 15 global event, according to Fridays for Future.

Different countries have different compositions of youth versus adult participation, the activists said. Belgium, for example, has seen tens of thousands of teenagers take to the streets. Sweden’s events are led by teenage Thunberg but probably attract about 80 percent adults, O’Keeffe said.

Italy started out leaning more towards adults, but every week more and more students have contacted Marder to ask how they can get organize new strikes or get involved with existing ones.

Profile Rising

Since the U.N. conference, Thunberg has been invited to speak at more and more high-profile international events.

In January, she spoke at the annual meeting of World Economic Forum in Davos, Switzerland. With her trademark twin braids and measured delivery, she told leaders, “I am here to say our house is on fire.”

Then on Feb. 27, Thunberg gave remarks preceding European Commission President Jean-Claude Juncker at the Commission’s “Civil society for rEUnaissance” event, where Juncker promised to invest more in fighting climate change.

Members of the European Green Party pointed out, though, that much could change during the budget negotiation phase.

Comparisons to AOC

Elena Grandi, the co-leader of the Italian Greens, compared Thunberg to freshman U.S. Rep. Alexandria Ocasio-Cortez.

Just as Ocasio-Cortez has helped the New Green Deal “go viral,” the Fridays for Future movement has helped unleash a “green wave” in Europe, Grandi said.

“In my opinion, Greta is one of those international phenomena,” she said.

Grandi has been a member of the Green Party for almost a decade and has never seen so much interest in climate change, she said. In just a month, the Italian Greens recruited 2 million volunteers to help with their environmental campaigns, working almost entirely through social media.

Still, it’s important that Fridays for Future remains youth-led and apolitical, Grandi said.

“This demonstration by the young people needs to come from the young people,” she said. “The question is: Who is able to take this and do something with it?”