ICE CORES MAY YIELD CLUES TO 5,000-YEAR-OLD MYSTERY
See Full Article at http://researchnews.osu.edu/archive/quelcoro.htm
The latest expeditions to ice caps in the high, tropical Peruvian Andes by Ohio State University scientists may shed light on a global climate change they believe occurred more than 5,000 years ago.
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| Lonnie Thompson |
The scientists hope to retrieve samples from ice caps as well as study plants from beneath the glaciers in hopes of finding clues about events which occurred in South America, Europe, and Asia.
Lonnie Thompson, Professor of geological sciences at Ohio State, believes something happened very abruptly approximately 5,200 years ago that affected a very large area.
In September, Thompson returned from Peru after having drilled three core samples from Nevado Coropuna, an extinct volcano in the Cordillera Occidental of the Andes. The third core is important as it may provide the climate history for this area for the last 2,000 years or more.
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| Map showing most recent and past drill sites Thompson’s team has drilled in Peru. |
This third core could also contain information which dates back more than 10,000 years and would provide much needed data to help understand the climate changes in this region of the world, including changes in El Nino and La Nina.
Thompson and his team have frequented this site many times over the past several decades, drilling other ice core samples in hopes of revealing annual records of climate dating back for more than 1,000 years. They also collected a sample from the summit which they hope will reveal annual records dating back more than 2,000 years.
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In 2002, Thompson and his team discovered a plant that had been perfectly preserved in ice, which DNA testing dated to 5,200 years ago. This is important, as something happened so abruptly that the plant was “captured” without being killed. What it indicates is that climate change happened very abruptly.
This year, Thompson and his fellow researchers found a second plant in the ice field approximately 4 miles from the first plant. Thompson believes the second plant may provide very important data about the site.
Carbon dating of the second plant showed that it had been buried some 2,200 years ago, indicating another abrupt climate change.
The ice caps in the area are also retreating rapidly. When Thompson began surveying the area, the glaciers were retreating at about 15.4 feet per year. More recently, they are retreating almost 672 feet per year–an increase of more than 40 times as fast.
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| Researchers found a plant deposit this year, revealed when the margin of the Quelccaya Ice Cap retreated. It was the second such find in the last two years. |
At least 70% of all tropical ice on Earth is trapped in the Peruvian glaciers and ice fields. Thompson and his team are fighting time to retrieve core samples from this region before the thousands of years of climate history contained within them is gone. And of utmost urgency is explaining what happened 5,200 years ago.
Little is known about abrupt climate changes in the tropics. But what is known is that if climate change happened very abruptly in the past, then it might happen again. And it would mean world-wide chaos, both socially and economically, as much of the world’s population lives in the tropics.
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Most of the studies on climate change have focused on greenhouse gases and a gradual increase in global temperatures. Recent evidence demonstrates that Earth’s climate repeatedly has shifted dramatically in time spans as short as a decade. Abrupt climate change may be more likely in the future.
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