(Newser) – At 15, Greta Thunberg has many decades of living with the effects of climate change ahead of her—and she doesn't want to tell her grandchildren she didn't try to stop it. At an address to the United Nations COP24 conference in Poland last week, the Swedish activist accused world leaders of stealing the future of her generation and said they weren't mature enough to act, CNN reports. "You say you love your children above all else and yet you are stealing their future in front of their very eyes," she told the conference, which was attended by delegates from 190 countries. Sen. Bernie Sanders tweeted video of her remarks, praising her for "calling out world leaders for their global inaction."

Thunberg accused leaders of only talking about "green eternal economic growth" because they were afraid of being unpopular. "You only talk about moving forward with the same bad ideas that got us into this mess even when the only sensible thing to do is pull the emergency brake," she said. "You are not mature enough to tell it like it is." Thunberg, who represented the Climate Justice Now network of groups, already has an extensive history of activism, the Washington Post reports. Earlier this year, she went on strike from school for three weeks and picketed the Swedish parliament, demanding radical action on climate change. She was nominated for the Children's Climate Prize but asked to be removed from consideration, saying in a tweet that a ceremony that involved flying people in from all over the world had "no connection with reality." (After two weeks, officials at the conference reached a deal described as a "thousand little steps forward.")

