Physical and chemical processes governing the climate of planets. Climate feedbacks and stability; greenhouse effect, ice-albedo feedback, cloud feedbacks. Effect of atmospheric circulation on climate. Milankovitch cycles and ice ages. Long-term atmospheric evolution; runaway greenhouse,SnowballEarth, atmospheric loss/collapse, faint young Sun problem. Interaction of climate with geology/biology. Observable signatures. Habitable zones. Application to Earth, Mars, Venus, Titan, and habitability of extrasolar planets.