Abstract
Since the end of the Pleistocene, the Santa Elena Peninsula in south‐west coastal Ecuador has undergone a series of climatic fluctuations that are the local manifestation of an Andean pattern of climatic change. The local archaeological record shows that in A.D. 600, and again in A.D. 1400, this region was struck by drought of such severity that the area was abandoned by its inhabitants. A number of specific details of this Ecuadorean sequence of marked climatic and sociocultural vicissitudes correlate with a contemporary archaeological sequence from the south coast of Peru. A hypothesis is proposed: climatic changes were factors underlying the rise and establishment of two prehistoric pan‐Andean highland states, the Huari‐Tiahuanaco empire about A.D. 600, and the later Inca empire about A.D. 1400.