They range in size from very small to very large. The smallest glaciers are only a few hundred meters long and the largest ones are giant ice sheets that cover huge areas like Greenland and Antarctica. Glaciers are an important source of water and can be used to supply water to places that have hot and dry summers. Also, the water that melts from glaciers can be used to make electricity. In the future, Antarctic glaciers may even be used to give water to places like Africa, the Middle East, and Australia.
Glaciers are also dangerous.
The study of glaciers is important because glaciers are sensitive to the climate changes of Earth. Scientists can measure the glaciers in order to know how much freshwater is on Earth.