Tundra: Earth's Largest Natural Region

The tundra biome covers approximately 20% of Earth's land surface (~11.5M km² / 4.4M sq mi) — the single largest natural region by area.

Distribution

• Arctic Tundra: North of treeline (60–75°N) — Alaska, Canada, Greenland, Scandinavia, Russia (vast).
• Alpine Tundra: Above treeline on mountains worldwide (Rockies, Andes, Himalaya, Alps, Africa, New Guinea).
• Antarctic Tundra: Antarctic Peninsula & islands — mosses, lichens, no vascular plants.

Defining Characteristics

• Climate: ET (Köppen) — mean warmest month 0–10°C. Short growing season (50–60 days).
• Permafrost: Continuous (Arctic) or discontinuous — ground frozen ≥2 years. Active layer thaws 0.3–1m.
• Vegetation: No trees. Mosses, lichens (reindeer moss), sedges, grasses, dwarf shrubs (willow, birch <1m), cushion plants, 1,700+ vascular species.
• Soils: Gelisols — organic-rich, cryoturbated (frost-churned), carbon-dense (1,600 Gt C — 2x atmosphere).

Fauna

• Residents: Muskox, caribou/reindeer, Arctic fox, lemming, ptarmigan, snowy owl, polar bear (coastal).
• Migrants: Millions of birds (shorebirds, waterfowl, passerines) breed in summer explosion.

Climate Change Frontline

• Warming 2–4x global average.
• Permafrost thaw → thermokarst, methane/CO₂ release, infrastructure collapse.
• Shrubification (taller shrubs) → albedo ↓, snow trapping, carbon cycle shift.
• Treeline advance → tundra displacement.

The tundra is Earth's carbon vault and climate sentinel. Its vastness belies its fragility — and its outsized role in planetary stability.