The analysis of an ice core extending 1600 years tells the climate story in the tropical Andes. The frozen sample cored from the Quelccaya Icecap
shows clearly defined layers of yearly light and dark bands with the light being from snow deposited during the wet season and dark being from the dust accumulations during the dry months. The research, conducted by Lonnie Thompson and his associates at Ohio State University
, was just published by Science Magazine.
The dating of the ice deposits timeline was made possible by plants frozen under the glacier when it originally advanced over them 1600-1800 years ago. Using radiocarbon dating
of the botanical tissues precisely determined the history of the glacial margins, now uncovered as bare ground and rock. From the new data, the melting of the Quelccaya icecap appears as fast, if not faster, than any time in the geological record since the Pleistocene
Quelccaya Glacier, 1978-2011 Yearly Ice Layers and Exposed Glacial Margins
(credit: Lonnie Thompson, OSU)
Besides uncovering the botanical and climate equivalent of a tropical "Rosetta Stone", the new data also tells a future story of water scarcity for populations now living in the Andes. If the rate of current melting continues, the life span of the life giving icecap can be calculated. Cities like Lima and others should be concerned as they are unlikely to be very resilient to losses of their water supplies.
The tropical Andes are experiencing climate change in 'real time' and the affects will be felt far away from where the Incas once made sacrifices to their frozen mountain gods. What took 1600 years to create has taken 25 to destroy.