Home to animals including Arctic foxes, polar bears, gray wolves, caribou, snow geese, and musk oxen, the Arctic tundra is changing in broad and somewhat unpredictable ways as global average temperatures rise. Its underlying base of frozen soil and plant matter, called permafrost, is thawing. That is turning the tundra into a source of greenhouse gas emissions, as soil microbes convert carbon into carbon dioxide and methane. The tundra is also slow to repair itself from physical disturbances such as tire tracks from heavy vehicles.

Thriving shrubs also crowd out lichen, an important food source for caribou and other animals. Warmer tundras could also see increased risk of wildfires