The cryosphere—from the Greek “kryos” (ice) and “sphere” (globe)—includes all those components of the planet that are frozen. Thus, it includes the snow, glaciers, the ice present in lakes, rivers, and oceans, and the subsurface layer permanently (permafrost) or seasonally frozen. Although a greater presence of elements of the cryosphere are concentrated in the polar regions, it also develops in large sectors of the temperate zones of the planet and even in the highest sectors of the tropical and equatorial regions. Due to its composition, mostly frozen water, and its reflective, mechanical and thermal properties, the cryosphere conditions numerous climatic, environmental and socio-economic processes.