Earth’s oxygen-rich atmosphere, the very thing that allows complex life to exist, may not last forever. Coupled biogeochemistry and climate simulations estimate that the planet’s breathable air could ...

New evidence from rocks, molecules and machine learning is forcing scientists to redraw the opening chapters of Earth’s story, pushing the first stirrings of biology far closer to the planet’s violent ...

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 ...