2013 Apr 4. In Sign of Warming, 1,600 Years of Ice in Andes Melted in 25 Years.

posted Apr 5, 2013, 9:39 AM by Alan Gould

http://www.nytimes.com/2013/04/05/world/americas/1600-years-of-ice-in-perus-andes-melted-in-25-years-scientists-say.html, by Justin Gillis, New York Times.  For GSS Climate Change chapter 8.   Excerpt: ...Glacial ice in the Peruvian Andes that took at least 1,600 years to form has melted in just 25 years, scientists reported Thursday, the latest indication that the recent spike in global temperatures has thrown the natural world out of balance.  The evidence comes from a remarkable find at the margins of the Quelccaya ice cap in Peru, the world’s largest tropical ice sheet. Rapid melting there in the modern era is uncovering plants that were locked in a deep freeze when the glacier advanced many thousands of years ago. Dating of those plants, using a radioactive form of carbon in the plant tissues that decays at a known rate, has given scientists an unusually precise method of determining the history of the ice sheet’s margins....