World-famous 16-year-old Swedish climate activist Greta Thunberg has thrown out a passionate challenge on climate change from the podium at the UN: "How dare you?" She has also informed world leaders, especially President Trump, that she and her millions of followers will not be silenced. In a sad and embarrassing scene, she has shown what it takes to silence her: Take away her script and ask her a question. It was a softball question: What kind of message would you like to give to world leaders? After some fumbling, she came up with "We have had enough," and "Would anyone...