The Little Ice Age The period of regional cooling from roughly 1300 to 1850 — glacial advances, frozen rivers, failed harvests — and what it reveals about climate sensitivity.
Ocean Currents Large-scale movements of seawater driven by wind, density differences, and Earth's rotation that redistribute heat around the planet.
Greenhouse Effect The warming of Earth's surface by greenhouse gases that absorb and re-emit infrared radiation, keeping the planet habitable.