With her typically blunt, often biting remarks, she has offered Americans a sort of unvarnished, outsider's view of themselves. And she has used the supersize attention she has received in this country to draw attention to her American peers, those young activists who have dutifully organised for climate action in their communities without any of the limelight that she has received.
"She's been quite selfless in this," said Xiuhtezcatl Martínez, 19, one of the 21 plaintiffs in a landmark children's lawsuit against the U.S. government. "I'm impressed with that."
Martínez has joined her in a number of her public appearances in New York and Washington, including at an Amnesty International awards ceremony this week, where Thunberg insisted on being onstage with her peers, rather than by herself. "A huge part of her messaging is, 'This is not for me,'" Martínez said.
On Wednesday afternoon, Thunberg joined her activist peers as they went to meet with the House speaker, Nancy Pelosi. She didn't want to say much, recalled Vic Barrett, 20, of White Plains, New York, who is also a plaintiff in the children's climate lawsuit. "She felt it was an opportunity for the US youth," Barrett said. "She's been very clear that she doesn't feel like all the attention needs to be on her."
Thunberg once described herself as "the invisible girl." She has never been fond of small talk. She still speaks very quietly and slowly. But she smiles much more than when she first began gaining media attention a year ago. She is more comfortable at banter, including with Trevor Noah, host of The Daily Show, who asked last week how it was to arrive in New York City after a two-week journey across the Atlantic on a solar-powered yacht.
She recalled the smell. "It was indescribable," she said, which prompted howls of laughter from the audience, also in New York City.
On Tuesday, speaking to members of a Senate task force, she spoke directly to earnest lawmakers who had commended youth climate activists like her for their courage. "Please save us your praise. We don't want it," she said. "Don't invite us here to tell us how inspiring we are without doing anything about it."
Jamie Margolin, 17, a Seattle-based activist who had been invited to the same meeting, was glad she called them out.
"She gives very blunt observations," Margolin said. "If I had done that, people would've thought I was an entitled brat."
"She comes with an outsider's perspective," Margolin added.
Thunberg explained her indignation this way on a CBS Good Morning interview: "We cannot focus on what we can and cannot say now," she said. "We must speak clearly about what's happening."
She has said she wants the global youth protests planned for Friday to be a "social tipping point."
Her earnestness comes out occasionally, like when she speaks to her peers. She often says she could not have imagined that school strikes, which she helped to inspire, would take off in so many countries. And she often speaks publicly about being "grateful."
"You will constantly feel like you are not doing enough," she said last week. "That is a very dangerous feeling to feel especially when you are actually doing everything you can."
"They are doing the impossible," she said of her peers. "I am eternally grateful for them."
Written by: Somini Sengupta
Photographs by: Anna Moneymaker
© 2019 THE NEW YORK TIMES