Quelccaya Ice Cap
From Wikipedia, the free encyclopedia
| Quelccaya Ice Cap | |
|---|---|
 |
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| Type | Mountain glacier/Icecap |
| Location | Peru |
| Coordinates | |
| Area | 44 km² (17 mi²) |
| Terminus | Outlet glaciers |
| Status | Retreating |
The Quelccaya Ice Cap is the largest glaciated area in the tropics. Located in the Cordillera Oriental section of the Andes mountains of Peru, the ice cap is at an average altitude of 5,470 meters (18,600 ft) and spans an area of 44 square kilometers (17 mi²). As has been found to be true for the majority of the Earth's glaciers, the Quelccaya Ice cap has retreated significantly since it was first studied, and since 1978, the icecap has lost 20% of its mass.[1] The rate of retreat for the ice cap has also been increasing. Comparing pictures taken in 1963 and 1978, an annual retreat rate of 4.7 meters (15.4 ft) was estimated. In the first few years of the 21st century, the annual retreat was measured to be as much as 205 meters (672 ft), more than 40 times as fast.[2] The major outlet glacier from the Quelccaya Ice Cap is the Qori Kalis Glacier, which has also retreated significantly since 1963.
[edit] Ice core study
Ice core samples taken from Quelccaya date back 2,000 years and show changes in atmospheric conditions. In these samples, the oxygen isotope ratio, oxygen-18 to oxygen-16, has risen abruptly in the last 50 years, a clear indicator of a widespread warming trend. As the glacial ice is retreating, it is exposing almost perfectly preserved unfossilized plant specimens that have been dated to 5,600 years ago, indicating that it has been more than 50 centuries since the ice cap was smaller than it is today.[3]
Ice core samples taken from Upper Fremont Glacier in the U.S. state of Wyoming have been shown to coincide with the changes in the Oxygen isotope ratio that were found in ice core samples from Quelccaya Ice Cap. Both samples showed this change to have ocurred during the mid 19th century, at the end of the Little Ice Age, which was a period of cooler global temperatures between the years 1550 and 1850. The sudden alterations in the Oxygen isotope ratio found in ice core samples from these two glaciers, which are at great distance from each other, provide evidence of a sudden global climate change in the mid-latitude regions of the planet.[4]
[edit] Cited references
- ^ *The Ice Plant Cometh. Science Bulletins. American Museum of Natural History. Retrieved on 2006-08-09.
- ^ Ice-Cores May Yield Clues to 5,000-Year-Old Mystery. NASA Earth Observatory (November 6, 2003). Retrieved on 2006-08-09.
- ^ Tropical Ice Cores Shows Two Abrupt Global Climate Shifts. Terradaily (June 25, 2006). Retrieved on 2006-08-09.
- ^ Reddy, M.M.; D.L. Naftz, P.F. Schuster. Ice-Core Evidence of Rapid Climate Shift during the Termination of the Little Ice Age. U.S. Geological Survey. Retrieved on 2006-08-09.
