Caribou are facing multiple threats from climate change. Historically the very cold air of the arctic holds little moisture, but warmer temperatures caused by global warming increase the amount of moisture the air can hold, so the region now sees more snow and freezing rain, which cover the ground with a thick, icy crust, making it difficult to reach the lichen they depend on for survival.
Climate change is also increasing summer droughts, leading to a higher risk of fire. Since the lichen caribou feed on takes 60+ years to grow, this can have a dramatic affect on their winter food supply.
Caribou are also threatened by a phenomena known as trophic mismatch. Plant growth is brought on by warming temperatures. However caribou begin their spring migrations based on the lengthening of days. As temperatures increase plants are blooming earlier. Now when caribou reach their typical spring birthing grounds they are finding plant life past its prime nutritional value and have to extend more energy for foraging.
Woodland caribou have been pushed toward extinction by poaching, and by logging and roads, which fragment and damage caribou habitat and bring increasing numbers of predators and motorized vehicles into caribou country. Snowmobiles pose a particular threat to the few remaining mountain caribou given their improved capacity to penetrate remote areas at high speeds, running caribou out of their last remaining habitat south of Canada.