Reindeer, also known as caribou, live in the chilly Arctic, tundra, and boreal biomes of the northern hemisphere. There are both sedentary and migratory populations of this species.
Accelerating Arctic warming has spelled erratic weather. Retreating sea ice and unseasonably warm weather contribute to heavy rains, which later freeze the snow cover for months, cutting off the reindeer’s lichen food supply.
In November 2013, 61,000 in a herd of 275,000 reindeer on the Yamal Peninsula in west Siberia starved to death when thick ice covered the land. This was a more intense recurrence of 2006, when 20,000 caribou succumbed to starvation. (These are just the documented incidents, after extensive research. Most loss of Nature goes unnoted.)
Reindeer are used to sporadic ice cover, and adult males can normally smash through ice around 2 centimetres thick. But in 2006 and 2013, the ice was several tens of centimetres thick. ~ Finnish ecologist Bruce Forbes
One subspecies of reindeer has already gone extinct. Caribou are not going to survive the erratic weather at the top of the world for much longer.