Glaciers and ice caps are excellent recorders of climate change, but satellites show that when they recede quickly, they can become potent symbols of warming trends throughout the world.
Peru’s Quelccaya Ice Cap is rare for several reasons. Situated at 13.5 degrees south latitude, it lies between the Tropic of Capricorn and the Equator, and it is the world’s largest tropical ice cap. This collection of glaciers grows on a high-altitude plateau in the Andes Mountains, between the Amazon jungle to the east and tropical, eastern Pacific waters to the west.
Because of its location, the ice cap captures chemical signatures of the cycles of El Niño and La Niña. Those signatures from the atmosphere are locked in ice cores that Lonnie Thompson and colleagues from The Ohio State University have drilled from Quelccaya, and they provide nearly year-by-year records of temperatures and atmospheric composition dating back 1,800 years.
Based on field and laboratory work by Thompson’s team—as well as three decades of satellite imagery—scientists also know that Quelccaya has been shrinking rapidly. The Thematic Mapper on the Landsat 5 satellite captured the accompanying images of Quelccaya in September 1988 and September 2010. Both images use a combination of visible, near-infrared, and shortwave infrared light.
Images courtesy of NASA.