Glaciers have been around for a long time. Many formed at the end of the last ice age, about 20,000 years ago. Since then, they have shaped Earth's landscape, helped cool the planet, and provided living things with fresh water--all while weathering changes in Earth's climate. Studying glaciers can tell us a lot about how Earth's climate has shifted over time, how human activities are impacting the climate, and what might occur in the future. Packed...