29
August
2018
|
05:49 PM
America/New_York

Documenting the demise of Quelccaya: The world’s largest tropical ice cap

For over 40 years, Ohio State University Byrd Center researchers have observed and documented the changes

Quelccaya_map_with_cap

COLUMBUS, Ohio -- From Aug. 14 to Sept. 4, 2018, researchers from Ohio State University's Byrd Polar and Climate Research Center (Byrd Center), Lonnie Thompson (team leader), Emilie BeaudonPaolo GabrielliRoxana Sierra-Hernández and Keith Mountain, along with three Peruvian researchers (Wilmer E. Sanchez Rodriquez, Oscar Vilca and Gustavo Valdiva), six film crew members from Boardwalk Pictures, Inc., and mountaineers led by Benjamin Vicencio will conduct a study of Earth’s largest tropical ice cap, Quelccaya, located in the southern Andes of Peru.

The melting of glaciers near populated areas is already affecting people whose livelihoods depend on glacial meltwater for crops and livestock and whose lives are endangered when glaciers collapse and/or glacial lake dams are breached. On regional to global scales the greatest near-term impacts will be economic, especially in countries that rely on glacial streams for agriculture, hydroelectricity, municipal water supplies, ecosystem support, tourism and recreation.

For over 40 years Lonnie Thompson and his colleagues have observed and documented the effects of the recent warming, augmented by strong El Niño events, on the ice fields in Peru. These ice fields are critical for agriculture and the overall economy of the country. Their research strongly suggests that the regional climate may be rapidly approaching a threshold beyond which future El Niños will have even stronger impacts on Peruvian glaciers than they have had in the past. Their goal is to use the data from this project to extend the history of strong El Niños and their effects on glaciers in southern Peru as such information will help the Peruvian government develop long-term strategies for coping with the impacts of future El Niño events.

Quelccaya is the longest monitored tropical glacier, with the first observations and snow pit sampling in 1974. Since then, its retreat has been systematically documented and today the 0°C isotherm rises seasonally above the ice cap’s summit, leading to the expectation that the retreat of this ice cap will accelerate in the coming decades. An important part of this project is to train the next generation of scientists who will continue documenting the loss of Quelccaya ice cap, as well as monitor the health of other glaciers in the Andes that also are currently at great risk to disappear. The three main objectives of the 2018 expedition include: (1) collecting snow and ice samples for chemical analysis from a snow pit and two 10-m deep cores from the summit (18,670 ft.); (2) taking terrestrial photographs of Quelccaya’s largest outlet glacier, Qori Kalis, to continue the photographic record of its retreat that began in 1978; and (3) searching for additional ancient plants that are exposed as Quelccaya’s margin continues to retreat. The oldest plant collected to date is 6,600 years old and confirms that the ice cap has not been smaller than it is today for at least 6,600 years.

The chemical and physical analyses of the new (2018) pit and core samples will be combined with those from numerous field seasons between 1974 and 2016 and will document the progression of the recent warming in this region that is also periodically intensified by strong El Niño events. Knowledge of the current chemical and physical signatures of strong El Niño events can then be used to shed light on the record of past variability which is preserved in the long Quelccaya ice core record that extends back 1800 years. The significance of these results may be further enhanced by comparing similar ice core-derived data from low-latitude, high elevation ice cores from the Himalaya and Tibetan Plateau to produce new knowledge about current and past intertropical atmospheric and oceanic teleconnections. The 2018 field expedition is sponsored by the VoLo Foundation and The Ohio State University.