Wilfried Haeberli, a glaciologist from the University of Zurich, describes how glaciers in Peru and around the world are been affected by climate change. He discusses the practical, short-term threats melting glaciers represent to humans who live near them or depend on them as a water source for agriculture.

"Glaciers have been retreating for more than 100 years worldwide, with very few exceptions. In global climate observation systems, they are often called unique demonstration objects of climate change...Everybody can see the change, and everybody can understand that ice melts when it gets warmer."

Photo by Dietmar Temps