Ron Smith, teaching Yale's Atmosphere, the Ocean and Environmental Change, examines how ice sheets and glaciers respond to and drive climate change. The lecture opens with mountain glaciers before turning to Greenland, where satellite measurements show two decades of rising surface melt and an overall decline in ice sheet mass. Smith then widens the scope to paleoclimate over the last five million years, contrasting the warm mid-Pliocene of 3.3 to 3 million years ago with the colder Pleistocene, which ended near the Last Glacial Maximum about 14,000 years ago, and the comparatively stable Holocene since. He shows how geomorphology, the study of landforms left behind, helps reconstruct how far continental ice once extended, and closes with a discussion of stable isotopes of water as a tool for reading past climate records. Chapter markers divide the fifty-minute lecture into clear sections tracking each topic in sequence.