Final answer:
The largest contemporary U.S. glacier is located in Alaska, which has experienced notable changes due to climate change, as evidenced by shrinking glaciers like the McCarty Glacier. The correct answer is option 1.
Step-by-step explanation:
The largest contemporary U.S. glacier is found in Alaska. Glaciers are dynamic systems that grow and shrink in response to changes in temperature and precipitation. The significant retreat of glaciers, such as those documented in Glacier National Park, is a visible effect of climate change. Glaciers in national parks like Glacier National Park are shrinking due to this global phenomenon. McCarty Glacier is an example of an Alaskan glacier that has completely disappeared, as shown in historical photo comparisons. Alaska hosts the largest glaciers in the U.S., and their changes are crucial indicators of environmental change.