White-tailed ptarmigan name "Tetrao (Lagopus) leucurus" by the Arctic explorer John Richardson in 1831. It was later determined that "Lagopus" had sufficient distinguishing features to be regarded as a separate genus and the bird became "Lagopus leucurus". Molecular studies have shown that "Lagopus" is monophyletic, with the rock ptarmigan ("Lagopus muta") and White-tailed ptarmigan being sister species. The position of the willow ptarmigan ("Lagopus lagopus") is less clear cut, it showing some genetic divergence over its wide range. The genus name "Lagopus" is derived from Ancient Greek "lagos" (λαγως), meaning "hare", + "pous" (πους), "foot", in reference to the bird's feathered legs.
Climate of the Arctic twice as much as the global mean temperature has. In 2009, NASA reported that 45 percent or more of the observed warming in the Arctic since 1976 was likely a result of changes in tiny airborne particles called aerosols. Climate models predict that the temperature increase in the Arctic over the next century will continue to be about twice the global average temperature increase. By the end of the 21st century, the annual average temperature in the Arctic is predicted to increase by , with more warming in winter ( than in summer. Decreases in sea-ice extent and thickness are