Final answer:
A glacier's growth or shrinkage is influenced by the balance between snowfall and melting. Climate change and natural climate cycles such as the Milankovich cycles also have significant impacts on glaciers. The glaciers in Glacier National Park have been shrinking due to rising global temperatures.
Step-by-step explanation:
Factors Influencing Glacier Growth and Shrinkage
The growth or shrinkage of a glacier, such as those in Glacier National Park, Montana, is controlled by the balance between snow accumulation and snow and ice melting. If the snowfall during winter exceeds the melt during summer, a glacier will grow. Conversely, if the melting outpaces the snow accumulation, the glacier will retreat. This balance is often referred to as the glacier's mass balance. Climate change is currently causing many glaciers to shrink, exemplified by the decrease in the number of glaciers in Glacier National Park from about 150 in the 1850s to only 24 by 2010. Factors such as global temperature changes, precipitation shifts, and larger climate patterns all play significant roles in affecting a glacier's mass balance.
Glaciers are also affected by long-term climate cycles, such as the Milankovich cycles, which involve changes in the Earth's orbit and axis. These changes can influence the amount of solar radiation the Earth receives, potentially leading to periods of glaciation or deglaciation. Additionally, human-driven climate change has been linked to glacier recession, as seen in the significant reduction of glacial mass in Greenland and the Antarctic, as well as the diminishing glaciers in Glacier National Park.