Abstract
The Arctic tundra biome occupies Earth’s northernmost lands, covering a 5.1 million km2 area that encircles the Arctic Ocean and is bound to the south by the boreal forest biome (Raynolds et al. 2019). Arctic tundra ecosystems are experiencing profound changes as vegetation and underlying permafrost soils are strongly influenced by rising air temperatures and the rapid decline of sea ice (see essays Surface Air Temperature and Sea Ice). By the late 1990s, an increase in the productivity of tundra vegetation became evident in global satellite observations, a phenomenon that continued and soon became known as “the greening of the Arctic.” Arctic greening is dynamically linked with Earth’s changing climate, seasonal snow, permafrost, and sea-ice cover, and remains a focus of multidisciplinary scientific research.
