An 1800-year Ice Core History of Climate and Environment in the Andes of Southern Peru and its Relationship with Highland/Lowland Cultural Oscillations

Climate is a fundamental and independent variable for human existence, as well as a factor in shaping the physical landscape within which human societies dwell. The record of human activities in South America before the arrival of the Spanish in 1532 is rich in archaeological remains but the process of reconstructing it is hampered by the lack of deciphered written languages. Through excavations of sites of precolonial civilisations in tropical South America, archaeologists have been able to unearth information about the chronology and activities of cultures in these regions. Climate variability may have played a significant role in the rise and fall of these civilisations, given that both coastal and highland populations were largely agrarian and located in climatically sensitive zones. The coastal cultures were heavily dependent on reliable water supplies, while the highland cultures, located near the upper limits of agriculture, were sensitive to variations in both precipitation and temperature (Paulsen 1976; Kolata 1986). This paper provides a climatic and environmental context of the Inca landscape that serves as a backdrop for the study of the Andean concept of ‘ushnu’ (Zuidema, this volume). In addition to rich cultural histories, tropical South America contains many types of archives of past climate and environmental change. Some of this evidence can be extracted from the ice fields of the Andes region, which contains over 70% of the world’s tropical glaciers. Because they have the capacity to record so many climatic and environmental indicators, glaciers serve as one of our best archives of climate change. Here we present 1800-year temperature and precipitation proxy records extracted from an ice core drilled through the Quelccaya ice cap located on the southern Peruvian altiplano. These histories help reveal the potential relationships between climate and the rise and fall of coastal and highland cultures in precolonial times, with emphasis on the period leading up to and during the Inca Empire. We present evidence for both decadaland century-length ‘El Niño-like’ oscillations and the role they may have played in the rise and fall of highland and coastal cultures in Peru as was argued in Thompson et al. 1994 and re-examined using new high-resolution ice core records recovered in 2003. It is serendipitous that these records were recovered from a location within the boundaries of the former Inca Empire, located less than ~100 km from the Inca capital of Cusco.