There are a number of positive feed back systems that help a glacier get back into balance with its environment. Glaciers forced to retreat because of climate warming will withdraw to a position where the temperature is lower. For example, valley glaciers will retreat to higher altitudes . A decrease in precipitation usually means a decrease in the rate and amount of ice moving through the glacier. This means that there is a decrease in ablation .
Increased precipitation has the opposite effect.
How quickly an ice body responds to an environmental change is called the response time. In general, the smaller the ice mass, the faster the response to a change in its environment. Valley glaciers will shrink much faster than a continental ice sheet if the climate warms and all other factors are equal. In fact, a large ice sheet might not react at all to temperature or precipitation changes that happen over the period of a year or even a decade. All factors being equal, if an ice mass is going to respond to a climatic change, the size of the ice mass is probably the dominant control on the response time.