New theory of Human evolution

Professor Mark Maslin (UCL Geography) and Dr Beth Christensen have edited a special issue of the Journal of Human Evolution which focuses on the connections between African palaeoclimates and early human evolution. The 13 papers in this volume tell a new and exciting story of how climate change may have caused new species of humans to emerge in Africa. It seems that when our ancestors evolved, the climate of Africa rapidly switched from wet and humid periods when the landscape was dominated by huge lakes over 300 m deep to arid barren periods when surface water was highly seasonal. Professor Maslin has called this the 'Pulsed Climate Variability' hypothesis as these periods of extreme climate variability last only a short period of time, and then for between half and one million years the climate of Africa calms down until the next highly variable period. Over 80% of the new hominid species in Africa emerge during these periods. It is suggested that the extreme environmental stress caused our evolution.