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Why is the Pleistocene Epoch often called the Great Ice Age?

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Map showing the extent of the Laurentide, Cordilleran, and Greenland ice sheets during the Wisconsin glaciation, roughly 100,000 to 11,000 years ago. The Laurentide Ice Sheet covers most of present-day Canada and parts of the northern United States in light blue, the Cordilleran Ice Sheet covers the Pacific Northwest in teal, and the Greenland Ice Sheet is marked in purple. Modern international and state or provincial boundaries are outlined for reference. — Pleistocene Epoch Ice sheets during the Wisconsin glacial episode penetrated deep into North America.

The Pleistocene Epoch is informally referred to as the "Great Ice Age" because it was characterized by a succession of glacial and interglacial climatic cycles. During this epoch, which spanned approximately 2.6 million to 11,700 years ago, extensive ice sheets and glaciers formed and retreated repeatedly across the Earth's landmasses.12

These climatic variations were driven by changes in the distribution of solar radiation across the Earth's surface, influenced by the geometry of the planet's orbit and the tilt of its axis. The epoch is defined by this continual flux between glacial and interglacial modes, which significantly shaped the Earth's surface. While the Earth has experienced other ice ages throughout its history, the Pleistocene is particularly noted for these dramatic and repeated expansions of ice into middle-latitude regions.324