dc.description.abstract | The development of the Cenozoic East African Rift System (EARS) profoundly re-shaped the
landscape and significantly increased the amplitude of short-term environmental response to
climate variation. In particular, the development of amplifier lakes in rift basins after three
million years ago significantly contributed to the exceptional sensitivity of East Africa to climate
change compared to elsewhere on the African continent. Amplifier lakes are characterized by
tectonically-formed graben morphologies in combination with an extreme contrast between high
precipitation in the elevated parts of the catchment and high evaporation in the lake area. Such
amplifier lakes respond rapidly to moderate, precessional-forced climate shifts, and as they do so
apply dramatic environmental pressure to the biosphere. Rift basins, when either extremely dry
or lake-filled, form important barriers for migration, mixing and competition of different
populations of animals and hominins. Amplifier lakes link long-term, high-amplitude tectonic
processes and short-term environmental fluctuations. East Africa may have become the place
where early humans evolved as a consequence of this strong link between different time scales. | en |