Department of Geography

Living with a changing climate

How have past societies responded?

MarcacochaSediments from the wetland site of Marcacocha in the Peruvian highlands have recorded a detailed palaeoclimatic history for the region over the last 4000 years

When the Spanish conquistadors arrived in Peru in the early sixteenth century they encountered the Inca, masters of the largest empire ever to have existed in the Americas. Today, a key to success across the Andes is related to efficient management of limited water resources and the ability to respond to changing climate by adapting agricultural and land-use practices. Are these the same challenges that faced the Inca? Certainly the Andean landscape is littered with the archaeology of earlier, failed cultures – so how were the Inca able to succeed so spectacularly where others had not? We have been able to tackle this and related questions concerning population size, trading activities, land use and large-scale demographic change by using a 4000-year record of climate change and human activity from a small, infilled lake site close to the Sacred Valley of the Inca. Our results have shown, for example, that despite living at a time of increased water stress, temperatures were warm enough to let the Inca move up the valleys and apply their irrigation and landscaping technologies to exploit higher altitudes. This ability to adapt means that the Inca were able to expand their population and develop food surpluses even when faced with difficult environmental conditions. It also let them maintain a standing army, which they employed ruthlessly to subjugate neighbouring cultures. This research also has implications for today’s Peruvians, who are once again facing a variety of environmental pressures (including water stress and landscape erosion) against a backdrop of global warming.

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Banner image: Mick Frogley