Greta Thunberg traveled for two weeks on a solar-powered sailboat to reach the United States this month.

Highlights Greta Thunberg was visibly emotional as she spoke at UN Climate Summit

You stole my dreams, childhood with empty words, she told world leaders

Ms Thunberg traveled for 2 weeks on a solar-powered sailboat to reach US

Teenage climate activist Greta Thunberg had one question for the global leaders assembled at the United Nations: "How dare you?"

Days after telling U.S. lawmakers "listen to the scientists," she made the same demand on an international scale. Thunberg chastised leaders for praising young activists like herself while failing to deliver on drastic actions needed to avert the worst effects of climate change, and she warned that if the world continued with business as usual, her generation would face an insurmountable catastrophe.

"This is all wrong," said Thunberg, who was visibly emotional as she spoke on a panel at a U.N. climate summit Monday. With tears in her eyes and her face flushed, the 16-year-old activist - who began skipping school in her native Sweden a year ago to protest inaction on climate change - chastised the world leaders who had gathered in New York.

"I shouldn't be up here. I should be back in school on the other side of the ocean," said Thunberg, who traveled for two weeks on a solar-powered sailboat to reach the United States this month. "Yet you all come to us young people for hope. How dare you?"

Thunberg has quickly become the face of a global movement of young people demanding that their elders safeguard their planet's future. On Friday, millions of young people all over the world joined Thunberg in a climate strike that she led from New York.

Thunberg continued her campaign Monday, as she and 15 other young people filed a legal complaint with the U.N. Committee on the Rights of the Child arguing that major countries - Argentina, Brazil, France, Germany and Turkey - have known about the risks of climate change for decades but have failed to take sufficient action to curb their emissions. The petitioners range in age from 8 to 17 and hail from Argentina, Brazil, France, Germany, India, the Marshall Islands, Nigeria, Palau, South Africa, Sweden, Tunisia and the United States.

"You have stolen my dreams and my childhood with your empty words," Thunberg said as she sat on the dais with panelists who included a young clean-energy entrepreneur from India and a Brazilian lawyer representing youth climate activists. "People are suffering. People are dying. Entire ecosystem are collapsing. We are in the beginning of a mass extinction, and all you can talk about is money and fairy tales of eternal economic growth. How dare you?"

"For more than 30 years, the science has been crystal clear," Thunberg added. "How dare you continue to look away and come here and say you're doing enough when the politics and solutions needed are still nowhere in sight? You say you hear us and that you understand the urgency, but no matter how sad and angry I am, I do not want to believe that, because if you really understood the situation and still kept on failing to act, then you would be evil, and that I refuse to believe."

Her remarks ended with a warning: "You're failing us, but the young people are starting to understand your betrayal. The eyes of all future generations are upon you. And if you choose to fail us, I say, we will never forgive you."

French President Emmanuel Macron appeared to respond to Thunberg less than an hour later when he addressed the gathering in French and called on his fellow leaders to take more ambitious action given the urgency of the climate threat.

"We've seen the emotion this morning," he said.

German chancellor Angela Merkel also met with Thunberg on Monday and posted a photo of her impromptu summit with the young activist.

But it was Thunberg's encounter with another world leader that garnered the most attention.

News cameras captured a video clip of Thunberg delivering an icy stare as President Donald Trump walked by, her mouth set in a rigid frown as he approached the assembled media. The Trump administration is working to roll back several Obama-era climate rules, and last week revoked California's ability to set tighter limits on vehicles' carbon emissions, a leading driver of climate change. In 2017, Trump announced that the U.S. would leave the landmark Paris climate agreement, though the terms of the agreement mean the U.S. cannot technically exit the deal until 2020.

Though Thunberg met with former president Barack Obama during her Washington visit last week, she has brushed off suggestions that she speak with Trump.

"Why should I waste time talking to him when he, of course, is not going to listen to me?" Thunberg told CBS News last month.

Her face on Monday, it appeared, said it all.