What causes glaciers to advance or retreat?

Glaciers advance or retreat depending on the balance between snowfall and melting. When snowfall exceeds melting, the glacier grows and advances downhill. Conversely, when melting outpaces accumulation, the glacier retreats, exposing previously covered ground. Factors such as temperature changes, precipitation, and human activities influence this balance. Glaciers are sensitive indicators of climate change and play a key role in regulating water cycles.