- biome receiving less than 250mm precipitation per year
- extreme diurnal temperature variation: scorching days, freezing nights
- covers ~33% of Earth’s land surface including hot, cold, and coastal types
- hot deserts: Sahara, Arabian, Sonoran; cold deserts: Gobi, Antarctic interior, Patagonian
- organisms exhibit specialized adaptations: succulence, nocturnality, deep root systems, dormancy
- soils are mineral-rich with low organic content, often with hardpan or salt crusts
- aeolian processes (wind erosion and deposition) shape dunes, mesas, and desert pavement
- sparse vegetation limits carbon cycle flux but desert dust fertilizes distant oceans
- oases form where groundwater intersects the surface, sustaining isolated ecology
- expanding due to desertification driven by climate change and land degradation
- solar energy potential is highest in desert climate zones