Our species likes it cold. Homo sapiens evolved in — and still inhabits — one of Earth’s rare and fragile ice ages, periods distinguished not by an abundance of saber-toothed cats and woolly mammoths ...

"Earth Day has always been an event of the people." On April 22, 1970, 20 million people across the globe celebrated the very first Earth Day. The idea was sparked by the power of the anti-war ...

Millions of people around the world will pause on Tuesday, at least for a moment, to mark Earth Day. It's an annual event founded by people who hoped to stir activism to clean up and preserve a planet ...