The Arctic Tundra: A Fragile Ecosystem Transforming Under Climate Pressure

The Arctic tundra — the vast, treeless biome that stretches across northern Alaska, Canada, Russia, Scandinavia, and Greenland — covers approximately 5.5 million square kilometres and represents one of Earth's most distinctive ecosystems. Characterised by permanently frozen subsoil (permafrost), an extremely short growing season of six to ten weeks, and plants adapted to survive months of darkness and temperatures that can drop below -50°C, the tundra is simultaneously fragile and resilient. It is also transforming at a rate that scientists describe as "unprecedented in the observational record."

The Tundra's Hidden Richness

Despite its apparent barrenness, the Arctic tundra supports over 1,700 species of vascular plants, hundreds of moss and lichen species, thousands of invertebrate species, and diverse communities of mammals and birds. The key to this richness is the brevity and intensity of the Arctic summer: when continuous daylight and temperatures above freezing coincide, biological activity is compressed into a few weeks of extraordinary productivity. Arctic plants grow rapidly, insects hatch in enormous numbers, and birds that have travelled thousands of kilometres to reach the tundra exploit this brief window of abundance to raise their chicks.

Arctic Greening — A Changing Tundra

Satellite data collected since the 1980s documents a dramatic phenomenon: the Arctic is greening. Shrub species — particularly dwarf birch and willows — are expanding in both density and geographic range across the tundra. The treeline is advancing northward. Grasses and sedges are replacing lichens and mosses in some areas. This "Arctic greening" is a direct response to warming temperatures — longer growing seasons and warmer summers allow taller, faster-growing plant species to outcompete the low-growing tundra specialists. The consequences cascade through the ecosystem: shrubs provide habitat for species not previously found in these areas, change snow distribution and albedo, and alter the carbon balance of the tundra.