Greta Thunberg speech at U.N.

Thunberg first turned up in the public spotlight when she delivered speech at a U.N. climate change summit earlier this month in which she accused the world's adults of acting like children.

"You are not mature enough to tell it like is," she said. "Even that burden you leave to us children. But I don't care about being popular. I care about climate justice and the living planet."