GLACIERS by Michael Hambrey & Jurg...

GLACIERS by Michael Hambrey & Jurg Alean (Cambridge University Press: $15.95; 208 pp., illustrated). Hambrey and Alean offer an interesting, approachable introduction to the vast rivers of ice. They explain how glaciers form and how they affect the landscape and human history. The average glacier moves between 50 and 400 meters each year: Their irresistible power was demonstrated in 1986, when the Hubbard Glacier blocked the mouth of Russell Fiord near Yakutat, Alaska. Although many glaciers appear to be in retreat, the authors note that scientists lack sufficient hard data to discern long-term patterns. The current interglacial period may end in a few thousand years, and ice will once again cover much of Europe, North America and Asia.