Ice caps and glaciers play important roles in the Earth’s systems. In this topic, we go through some of the basic physical definitions and classifications of such ice masses to set the scene for the rest of the talk and demonstrate some of the routes through which they are important to Earth’s systems. In the simplest physical terms, ice caps and glaciers are defined depending on the way they flow. An ice cap is defined as ice that flows radially from a central or high axial location. Glaciers, on the other hand, are defined as ice that moves along a valley or belt of low slope. Ice masses can have a mixture of flow patterns and can be classified in other ways, for example, by the way they move or the spatial extent of their covers. Polar ice caps and glaciers are called extremely cold regions and provide the only area of land permafrost in the world, therefore becoming an important sensitive layer in the cryosphere. As a small-scale glacier, ice caps broadly distribute in polar areas, seacoasts, the southern edge of the permafrost region in the high-altitude alpine areas of the plateau, and the northern plateau in western China. There are various types of landforms formed by conglomerated ice, including ice caps, shelves, and bergs. The ice caps are distributed in both polar regions and polar land of the world. Some dry valleys in the ice-free area at the eastern edge of Antarctica have glacier widths of less than 2 km, and these are actually ice caps. Most ice caps are located along the coastlines with marine structures.