Dark night skies are environments undisturbed by light and air pollution. Dark night skies have natural, cultural, and scenic importance. Wildlife is impacted by light pollution because animals often depend on darkness in order to hunt, conceal their location, navigate, or reproduce. For nocturnal animals, light pollution also means habitat disruption. Additionally, many species have far more sensitive vision than humans. Plants are affected by artificial light because it disrupts their natural cycles.
Dark night skies are also culturally important because they are a resource common to all cultures on Earth, and are a metaphor for countless myths and religions. They have inspired innumerable works of art, literature, and connections to the cosmos.
Natural lightscapes, including dark night skies, are a scenic resource integral to many people's Waterton-Glacier experience. Currently, two-thirds of Americans cannot see the Milky Way from their backyard, and if current light pollution trends continue, there will be almost no dark skies left in the contiguous United States by 2025. Many people seek national parks to experience this vanishing resource. Waterton-Glacier hopes to provide and preserve this important opportunity by meeting the requirements and objectives of Dark Sky Parks.
Glacier National Park and its sister park Waterton Lakes National Park of Canada have been designated an International Dark Sky Park by the International Dark Sky Association (IDA). This is the first IDA designation in the world to cross an international border. The designation requires a long-term commitment to preserving dark skies and requires the parks to meet specific objectives. These include preservation or restoration of outstanding night skies, protection of nocturnal habitat, public enjoyment of the night sky and its heritage, and demonstrating environmental leadership on dark sky issues by communicating the importance of dark skies to the general public and surrounding communities, and by providing an example of what is possible.