It’s the 50th Anniversary of Earth Day, and on the show we wanted to talk about where there is possibility and hope in tackling climate change—so we’re focusing on youth voices and science. Those are the two places that give us the most hope. Today, we’re featuring Time’s 2019 Person of the Year, Greta Thunberg, and her powerful, urgent speech at the United Nations last fall. Then we encore an interview with Becky Alexander, Professor in the Department of Atmospheric Sciences Director and Program on Climate Change at the University of Washington, who explains the difference between pollution and carbon emissions and what it’ll take to get a hold on the runaway crisis of climate change.