Final answer:
The subject matter deals with the history and geography of Glacier National Park's glaciers, which have retreated from over 150 at the end of the Little Ice Age to just 26 remaining active named glaciers as of 2015.
Step-by-step explanation:
The question pertains to the changes in the number and size of glaciers in Glacier National Park (GNP) over time. The glaciers that carved the park's landscape ended their formation about 12,000 years ago, while the current alpine glaciers formed around 7,000 years ago, growing significantly during the Little Ice Age. The end of the Little Ice Age around 1850 saw these glaciers at their maximum extent, as evidenced by moraines and historical aerial photography. Unfortunately, as of 2015, only 26 active named glaciers remain out of the over 150 that were present at the end of the Little Ice Age.
Glacier National Park once had a significant number of glaciers during the Little Ice Age, but due to glacier retreat, the number has dramatically decreased. For more information about the effects of climate conditions on glacier size, refer to sources like the U.S. EPA's climate change indicators or the National Snow and Ice Data Center World Data Center for Glaciology.