Swedish climate activist Greta Thunberg was named Time’s “person of the year” Wednesday, becoming at age 16 the youngest person to whom the U.S. magazine has given the title. Thunberg emerged as the face of the youth climate movement after she started skipping school once a week to protest outside her country’s parliament. In the past year and a half, she has drawn large crowds at international conferences and demonstrations outside Sweden. Some have welcomed Thunberg’s environmental activism, including her speeches challenging world leaders to do more to stop global warming. But others have criticized the teenager’s sometimes combative tone. “For sounding the alarm about humanity’s predatory relationship with the only home we have, for bringing to a fragmented world a voice that transcends backgrounds and borders, for showing us all what it might look like when a new generation leads, Greta Thunberg is TIME’s 2019 Person of the Year,” the media franchise said Wednesday on its website.