biome characterized by permafrost, minimal tree growth, and extreme cold
two types: arctic tundra (high latitude) and alpine tundra (high altitude)
short growing season of 50-60 days limits vegetation to mosses, lichens, grasses, and dwarf shrubs
permafrost layer stores massive quantities of frozen carbon cycle reserves
thawing permafrost releases methane and CO2, creating a climate feedback loop
fragile ecology: slow recovery from disturbance due to extreme conditions
supports migratory species: caribou, arctic foxes, snowy owls, millions of nesting birds
soil is thin, waterlogged in summer, and nutrient-poor
alpine tundra occurs above treeline on every continent with mountains
acts as a sensitive indicator of planetary warming trends
covers ~10% of Earth's land surface