Clues in ancient mud hold answers to climate change

New research suggests that Africa has gradually become wetter over the past 1.3 million years -- instead of drier as was thought previously.
The research from Berke, assistant professor in the Department of Civil and Environmental Engineering and Earth Sciences at the University of Notre Dame and Environmental Change Initiative affiliate, suggests that Africa has gradually become wetter over the past 1.3 million years -- instead of drier as was thought previously. The findings shine new light on the "savanna hypothesis," which held that humans in Africa as a whole migrated to grasslands due to a changing climate.
The sediment samples that Berke studied came from Lake Malawi in southeast Africa, whereas data used for the savanna hypothesis came from the north. Her research suggests that climate conditions across Africa may have been more variable than once thought.

Importantly, Berke's samples also reflect the longest continuous record of temperature data ever collected on the African continent. Apart from their age, the materials she analyzed were of exceptional quality.
"Lake Malawi is one of the deepest lakes in Africa, and the sediment samples taken from it are finely laminated. You can readily see how it changes across intervals of time," said Berke.