Human Development and Climate (Excursus)

Climate and biological evolution have been closely linked throughout Earth’s history. Climate plays a role in the evolution and adaptation of hominini (hominids) not only in the past, but – presumably – also in the future. Much has been discussed about feedbacks between climate variability and human evolution. Various hypotheses assume that the climatically induced environmental changes of the last 7 million years were responsible for hominin speciation, for the morphological change to an upright bipedal gait, to larger brain volume, to adapted behaviour (behavioural adaptability), to cultural innovations (use of stone tools since 3.3 Ma; regular use of fire since 0.5 Ma) and intercontinental migrations. These hypotheses are based on correlations of global climate changes stored in marine and terrestrial climate archives with events in hominin evolution documented in terrestrial fossil-bearing sediments. Establishing cause-and-effect relationships between climate and human evolution is tedious, but opens up numerous challenges for palaeoanthropology and the geosciences. Major climate proxies and hominini evolution are contrasted. The relationships between climate and environmental change, on the one hand, and the origins of the Hominini, on the other, must be built on a theoretical foundation in conjunction with a causal understanding of the relationships between climate, environment, resource distribution, Hominini behaviour, and Hominini morphology. The strict correlative research that often still dominates today must be overcome.