Wet weather forced people out of Africa
Analysis of mud from the bed of Lake Malawi (above) in southeast Africa has revealed that Homo sapiens was able to migrate out of Africa because of a shift to wetter weather.
By analysing a detailed climate record preserved in sediment cores from the lake, a team of scientists from Syracuse University in New York state, USA, revealed that between 135,000 and 75,000 years ago, the region experienced several severe droughts, which caused the lake to drop to a depth of 100 metres. Five thousand years later, the climate appears to have stabilised, with a more consistent level of rainfall, raising the lake’s level by as much as 600 metres. According to the study, this shift to wetter weather 70,000 years ago enabled people to travel over longer distances, gaining sustenance from a landscape that was previously too barren to traverse.
Author of the study Christopher Scholz corroborated the data from the sediment cores – some of which were extracted from a depth of 400 metres – with that of genetic studies of early human movement patterns.
November 2007
By analysing a detailed climate record preserved in sediment cores from the lake, a team of scientists from Syracuse University in New York state, USA, revealed that between 135,000 and 75,000 years ago, the region experienced several severe droughts, which caused the lake to drop to a depth of 100 metres. Five thousand years later, the climate appears to have stabilised, with a more consistent level of rainfall, raising the lake’s level by as much as 600 metres. According to the study, this shift to wetter weather 70,000 years ago enabled people to travel over longer distances, gaining sustenance from a landscape that was previously too barren to traverse.
Author of the study Christopher Scholz corroborated the data from the sediment cores – some of which were extracted from a depth of 400 metres – with that of genetic studies of early human movement patterns.
November 2007
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