Evidence and Impact

Flathead Lake, Montana
FunGi-Flickr
More than 80 percent of Glacier National Park’s glaciers have disappeared since 1850 and the few remaining are expected to disappear within 15 years.

The most obvious factor influencing the glaciers’ decline is gradually warming temperatures that result in more very hot days in the summer and fewer cold days in the winter. These warmer temperatures impact natural systems throughout the Crown.

Water

The loss of glaciers diminishes water flow during the summer, which impacts native trout. Trout rely on the cold, clear glacial melt to keep stream temperatures cool during the summer.

Trout rely on the cold, clear glacial melt to keep stream temperatures cool during the summer.

Bark beetles

Warmer, often drier conditions throughout forests in the Crown have led to increasing infestations of insects that kill trees and ruin forest views that Montanans have long enjoyed. 

Mountaintop plants and wildlife

Warmer temperatures cause subalpine fir trees to expand into alpine meadows. Mountain goats now have fewer alpine meadows in which to graze. Some wildlife will move up in elevation as their habitat changes, but others, like those already living on mountaintops, have nowhere to go.