In 1856 a scientist and women's rights campaigner in upstate New York set glass jars of different gases in the sun and noticed that the one filled with carbon dioxide grew hottest. A century later a young chemist began logging the air on the slope of a Hawaiian volcano, and his numbers climbed every single year. Since then, scientists have drilled ice that holds bubbles of air older than our species, dropped thousands of robots into the ocean, and watched from orbit as glaciers thin. Each clue, gathered by different people with different tools, points to the same conclusion.

This course follows that evidence step by step. You will learn how the greenhouse effect keeps Earth livable, how carbon moves between air, ocean, life and rock, and what ice cores reveal about ice ages and ancient hothouse worlds. You will weigh the measurements that show the planet warming and the fingerprints that reveal why, see how feedbacks turn a small push into a large change, and look inside the models scientists use to test the future. You will finish by exploring what warming means for heat, water, coasts and coral reefs, and what the physics says about the choices still in our hands.