Glaciers and Ice Ages Explained — Formation, Landforms, and Climate Impacts | Chapter 22 from Earth: Portrait of a Planet
Glaciers and Ice Ages Explained — Formation, Landforms, and Climate Impacts | Chapter 22 from Earth: Portrait of a Planet How have glaciers and ice ages transformed our world? Chapter 22 of Earth: Portrait of a Planet by Stephen Marshak explores the powerful role of ice in shaping Earth's surface, influencing sea levels, and driving global climate. For a podcast summary, watch the chapter video on YouTube , or read on for a detailed educational guide. How Glaciers Form and Move Formation: Glaciers develop as snow compacts into firn and then recrystallizes into ice. Types include mountain (alpine) glaciers—valley, cirque, piedmont, ice caps—and massive continental ice sheets (Greenland, Antarctica). Glacier Movement: Glaciers move by plastic deformation and basal sliding. The upper zone is brittle, forming crevasses; deeper ice flows more plastically. Surges can rapidly advance glaciers. Advance vs. Retreat: The position of a glacier’s terminus depends on the b...