Greta Thunberg, the 16-year-old Swedish climate activist, captured global attention with her emotional speech at the United Nations in September. Her relentless advocacy for an international focus on climate change has raised awareness as few prior activists have managed to. Critics see her youth as evidence Thunberg isn’t serious, or is being manipulated by the adults around her. Defenders say it makes her more credible, as a possible future resident of a catastrophically warmed planet. One thing, however, is clear: Thunberg is not the first of her kind. She stands on the shoulders of decades of teenage climate activists who were doing the work without funding, before social media, and certainly before heads of state were calling children “leaders” of any kind.

My first exposure to the international community of youth climate activists was at the 2013 Warsaw U.N. climate change Conference of the Parties (COP): A person in a Tyrannosaurus rex costume was accompanied by a group of students singing a song about the environmental rights group Climate Action Network’s “Fossil of the Day” award—a distinction given to the country with the most counterproductive actions, like supporting coal-powered plants or refusing to agree to larger greenhouse gas emissions cuts. There were hints of the emotional toll climate change, and countries’ inattention to it, was taking on these kids, who came both from developed countries and also from all over Africa, the Philippines, Fiji, and the Caribbean islands. It may have looked like a skit, but only because there was no space for the visceral anger and frustration that today’s youth activists have.

Tone Bjørndal, now 26 and working for a Norwegian climate advocacy group, was just 16 when she attended her first COP—one that would become a disastrous foreign policy failure. It was in 2009 in Copenhagen. There were 2,000 teenagers and college students in her group, called the Youth Constituency of the U.N. Framework Convention on Climate Change (YOUNGO), she told me. The U.N. recognized their presence in this titular way, but elsewhere made it clear the teens weren’t to be treated as true stakeholders.

The group, composed of kids who had traveled on what little private and public funding they could scrounge up, was expecting 120 passes to the conference—usually attended by more than 20,000 delegates, U.N. staff, and members of the media—but received only two passes on the opening day. “We gave up on the line,” she wrote in an email to her parents at the time. “We waited 4.5 hours, and they told us it would be three to seven more—we were freezing, angry, and frustrated.”

Nathan Thanki, 28, a former YOUNGO participant who now works for the Global Campaign to Demand Justice in London, told me that despite the efforts of a few of his professors and some NGOs, who sponsored young students from around the world to attend these meetings, most people at the time dismissed young activists. “We were not respected that much by the people in the UNFCCC secretariat or the COP presidencies or chairs of various bodies—many of whom can be quite patronizing, especially to young people, and especially to those they deem ‘radical,’” he said.