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the timing and extent of abrupt climate changes and their
consequences for civilizations of the time. However, the
majority of the Mesoamerica and South American writing
systems identi
southern Peruvian mountains. Alternatively, the lowland
cultures appear to have dominated during periods of below-
average precipitation in the mountains, when the precipita-
tion was higher in the coastal regions [Paulsen, 1976]. Such
variations in rainfall would have profound consequences for
societies that were highly dependent on agriculture and ex-
isted in climatically sensitive environments [Cardich, 1985].
Under present climate conditions, coastal Peru experiences
higher than normal rainfall during ENSO events, while the
highlands, where Quelccaya is located, experience drier than
average conditions [Tapley and Waylen, 1990]. Based on the
geographical and temporal patterns of societal rise and fall in
preconquest Peru, it appears as though this spatial pattern of
climate variability might have occurred on decadal to cen-
tennial time scales in a manner similar to the precipitation
distributions governed by the modern ENSO. Archeological
evidence shows that during the Late Intermediate period, the
southern coastal climate in the region of Peru was relatively
humid, then became more arid after ~600 A.D. [Eitel et al.,
2005; Mächtle et al., 2006], while the Quelccaya ice core
record shows variably above-average accumulation (i.e.,
precipitation) during this period when the Huari Highland
culture dominated. During the twentieth and beginning of the
twenty-
ed before the arrival of the Spanish in 1531
C.E. have not yet been deciphered. In Peru, a succession of
preconquest societies such as the Huari (or Wari), the Moche,
and the Incas lived in the coastal areas and the highlands, but
the only evidence of their rise and demise (other than the
Spanish accounts in the case of the Incas) comes from oral
tradition and archeological
findings. Highland and coastal
cultures flourished and waned out of phase with each other
from the Early Intermediate period to the Late Horizon
[Paulsen, 1976], which ended with the destruction of the
Inca Empire by the Spanish conquistadors (see Figure 4).
Although written accounts are lacking, the climate record
derived from the Quelccaya ice core, Cordillera Vilcanota,
southern Peru (location in Figure 1), allows reconstruction of
the highland climate and environment in this region of the
Andes, especially during critical periods such as the alternat-
ing rise and fall of the preconquest agrarian civilizations
from the Early Intermediate period to the abrupt disruption
of indigenous societies in the mid-sixteenth century C.E.
(Figure 4) [Thompson et al., 1994]. The highland cultures
(Huari and Inca) existed during two periods, the Middle
Horizon from 600 to 1000 C.E. and the Late Horizon from
1450 to 1530 C.E., when the Quelccaya ice core records
show above-average ice accumulation (Figure 4) in the
rst century, population migration has been from the
highlands to the coastal deserts since at least the 1940s as
illustrated in the map of modern population distribution
(Figure 4). The longer-term history of the rise and fall of
Figure 4.
The reconstructed ice accumulation record from the Quelccaya Ice Cap, compared with the Peruvian coastal and
highland archeological history from the
fifth century C.E. to the Spanish conquest in the 1532 C.E. Map shows modern
population distribution which is largely concentrated in the coastal desert areas of Peru.
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