What Is Albedo?

Albedo (from Latin "albus" meaning white) quantifies reflectivity. Fresh snow has an albedo of 0.80-0.90 (reflecting 80-90% of sunlight), while dark ocean water reflects only about 0.06 (6%). Earth average albedo is about 0.30 — meaning 30% of incoming solar energy is reflected back to space, primarily by clouds, ice, snow, and deserts. Albedo is central to climate feedbacks: as Arctic sea ice melts, it exposes dark ocean water (low albedo), which absorbs more heat, causing more ice to melt — a positive feedback loop called the ice-albedo feedback that amplifies Arctic warming. Conversely, large volcanic eruptions can increase planetary albedo by injecting reflective sulfate aerosols into the stratosphere, temporarily cooling the climate. Some geoengineering proposals aim to artificially increase Earth albedo by brightening clouds or placing reflective materials in orbit.