Warming at high latitudes, documented in both AR4 and AR5, is leading to earlier snow and sea ice melt and longer growing seasons  which are continuing to alter tundra plant communities  . Woody encroachment and increases in vegetation productivity, observed in both AR4 and AR5, are widespread and continuing. Both experiments and monitoring indicate that climate warming is causing increases in shrub, grass and sedge abundance, density, frequency, and height, with decreases in mosses and/or lichens  . Shrub growth is climate-sensitive and is greater in years with warmer growing seasons . Plant species that prefer warmer conditions are increasing , plant cover is increasing and bare ground is decreasing in long-term monitoring plots . Animals such as moose, beavers and songbirds may already be responding to these vegetation changes by expanding their ranges northward or upslope into shrub tundra .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report