Fig. 2: Climatic Windows of opportunity out of Africa.
From: Climatic windows for human migration out of Africa in the past 300,000 years
a Distribution of modern hunter-gatherer populations (histograms)36 under different precipitation levels and in relation to grazer biomass density39 (black markers). Transparent bins correspond to populations located in close vicinity of a water source, which are not considered to be constrained by precipitation. b, c Percentage of decades within a given millennium (x-axis) during which a connected path between Africa and Eurasia along the b northern and c southern route existed for a given hunter-gatherer tolerance to low precipitation (y-axis). The green band represents our empirically estimated threshold of 90 mm y−1.
