Annually Resolved Ice Core Records of Tropical Climate Variability over the Past ~1800 Years

• Published in: Science
• Main Authors: Thompson, L. G., Mosley-Thompson, E., Davis, M. E., Zagorodnov, V. S., Howat, I. M., Mikhalenko, V. N., Lin, P.-N.
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Association for the Advancement of Science (AAAS) 2013
• Subjects: Greenland; Antarc*; Antarctica; Ice cap; ice core; Ice Sheet
• Online Access: http://dx.doi.org/10.1126/science.1234210; https://www.science.org/doi/pdf/10.1126/science.1234210

Quelccaya Ice Cap Ice cores drilled in the ice sheets of Greenland and Antarctica are some of the most important sources of information about the paleoclimate of high latitudes. Comparable records from the tropics are rare, however, because there are so few locations at which long-lived, undisturbed ice can be found. Thompson et al. (p. 945 , published online 4 April) report results obtained from one of the few such sites, the Quelccaya ice cap in the Peruvian Andes. The annually resolved data, extending back 1800 years, provide a detailed chronicle of changes in the isotopic composition of the oxygen in the ice, which are related to the sea surface temperature of the water's source. Analyses of a collection of major ions such as ammonium and nitrate reveal how atmospheric circulation in the region varied over that period. Finally, the radiocarbon content of ancient plants—recently exposed by the retreat of the ice sheet—reveals that Quelccaya has not been smaller for at least six thousand years.