Teen climate activist Greta Thunberg addressed the World Economic Forum in Davos, Switzerland, on Tuesday, tearing into world leaders whom she accused of "fueling the flames" of climate change with their inaction. She delivered the opening remarks on a panel entitled "How to Save the Planet: Averting a Climate Catastrophe."

In her remarks, she told the gathered business, political and NGO leaders that simply planting trees was "not enough," in what appeared to be a veiled swipe at President Donald Trump's announcement just a couple hours earlier that the U.S. was joining an international initiative to plant 1 trillion trees. Mr. Trump, in his opening address in Davos, also said it was time to reject the warnings of "prophets of doom and their predictions of the apocalypse."

Thunberg accused politicians of all stripes of making promises but failing to deliver any results, and she demanded an immediate end to all investment in fossil fuels.

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"We want this done now," she said. "It may seem that we are asking for lots, and you will of course say we are naive," but she said she and the children who support her around the world were actually seeking the "bare minimum" necessary to address what she calls the climate crisis facing the planet.

"Our house is still on fire. Your inaction is fueling the flames by the hour, and we are telling you to act as if you loved your children above all else," the young campaigner said.

Young activists take center stage

Earlier Thunberg took part in a panel discussion with other youth climate activists titled, "Forging a Sustainable Path Towards a Common Future," at which she called for "science and voice of young people" to be put at the center of the global conversation about climate change.

"It is about us and future generations and those who have been affected today," Thunberg said. "We need to bring the science into the conversation."

Fellow participants in the youth panel included Salvador Gómez-Colón, founder of Light & Hope for Puerto Rico; Natasha Mwansa, an 18-year-old reporter and advocate for children's and women's rights in Zambia; and Autumn Peltier, the 13-year-old chief water commissioner of the Anishinabek Nation in Northern Ontario.

"The older generation has a lot of experience, but we have ideas, we have energy, and we have solutions," Mwansa said.

Gómez-Colón, who raised money and awareness after Hurricane María devastated his native Puerto Rico in 2017, said young activists are doing more than just talking.

"We're not waiting five, 10, 20 years to take the action we want to see. We're not the future of the world, we're the present, we're acting now. We're not waiting any longer," he said.

You can watch the full panel in the video player below:

The Associated Press contributed reporting.