Arctic tundra
The Arctic tundra is a treeless biome of northern high latitudes, with frozen ground, low-growing vegetation, and short growing seasons.
Permafrost: Ground that remains at or below 0°C for at least two consecutive years. Its shallow summer thaw limits rooting depth and controls drainage across much of the tundra.
Tundra: A cold, largely treeless biome characterized by low-growing vegetation and a short growing season. The Arctic is one major regional form of tundra.
Arctic climate change: The rapid warming and associated environmental changes occurring across the Arctic region. Warming alters snow, permafrost, vegetation, and the length of the tundra growing season.
Alaska North Slope: The Arctic coastal plain and foothills of northern Alaska. Its tundra includes extensive wetlands, permafrost, and major wildlife habitats.
Arctic shrub expansion: The spread or increased growth of shrubs into Arctic areas previously dominated by shorter vegetation. Shrub expansion changes snow cover, habitat structure, and energy exchange across tundra.
Active layer: The surface layer of permafrost terrain that thaws during summer and refreezes in winter. Its depth determines how much soil and plant-root activity the brief summer permits.
Growing season: The part of the year when environmental conditions permit plant growth. Its brevity constrains flowering, seed production, and plant establishment in the Arctic.
Permafrost carbon cycle: The exchange and storage of carbon in permafrost soils and ecosystems. Tundra thaw can release carbon previously stored in frozen organic matter.
Siberian tundra: A broad expanse of Arctic tundra across northern Siberia. It illustrates the biome’s immense east–west variation in climate and ecosystems.
Permafrost thaw subsidence: The sinking of land as thawing, ice-rich permafrost loses volume. Subsidence damages infrastructure and reshapes drainage in tundra communities.