Today is Earth Day, a good occasion as any to reflect on the emergencies the planet currently faces. First, Harriet A. Washington, author of A Terrible Thing to Waste: Environmental Racism and Its Assault on the American Mind, talks to NPR's Sarah McCammon about the long-term damage environmental issues can have on brain development—particularly for people of color. Next, the author David Wallace-Wells talks to NPR's Rachel Martin about his book The Uninhabitable Earth, which is a lot more hopeful than the title might suggest. He runs through the worst-case scenarios climate change could wreak, and why every effort we make against further global warming matters.