Rainfall and drought in equatorial east Africa during the past 1,100 years

摘要: Knowledge of natural long-term rainfall variability is essential for water-resource and land-use management in sub-humid regions the world. In tropical Africa, data relevant to determining this are scarce because lack long instrumental climate records limited potential standard high-resolution proxy such as tree rings ice cores. Here we present a decade-scale reconstruction drought equatorial east Africa over past 1,100 years, based on lake-level salinity fluctuations Lake Naivasha (Kenya) inferred from three different palaeolimnological proxies: sediment stratigraphy species compositions fossil diatom midge assemblages. Our indicate that, millennium, has alternated between contrasting conditions, with significantly drier than today during 'Medieval Warm Period' (approximately AD 1000-1270) relatively wet 'Little Ice Age' 1270-1850) which was interrupted by prolonged dry episodes. We also find strong chronological links reconstructed history variation pre-colonial cultural highlighting importance detailed knowledge sustainable socio-economic development.