indicates a short climatic deterioration from about 14,300 to 14,100 cal BP, tentatively correlated with the GI-1d event.
"Modern humans during [this] period were in central Europe at least 2,000-3,000 years before this climatic deterioration, when huge icebergs calved from ice sheets in the northern Atlantic and temperatures plummeted," said Prof Higham.
Deviations from the high SSTs occur as two cold snaps, i.e. short periods of extreme climatic deterioration (Table 2; Fig. 2): (1) SSTs from 26.2 °C to 28.2 °C occur between ~ 17.85 Ma and ~ 17.86 Ma (max. range: 18.02 17.59 Myrs); (2) the lowest SST of 24.1 °C for all samples has been calculated for sample HO 450 (~ 17.81 Ma) (max. range: 17.96 17.55 Myrs).
Since the climatic deterioration at 33 Mya, the temperature began to fluctuate from the early Oligocene to the middle Miocene (34 15 Mya) [ 99].
Climatic deterioration, resulting in drier conditions and thus a diminished subsistence potential, may have been a factor.
"Faced with this kind of competition, the Neanderthals seem to have retreated initially into more marginal and less attractive regions of the continent and eventually, within a space of at most a hundred thousand years, for their populations to have declined to extinction – perhaps accelerated further by sudden climatic deterioration across the continent around 40,000 years ago".
The transition from a humid to an arid climate after ∼5900 14C yr B.P. coincided with enhanced aeolian activity, and deciduous woodlands were replaced by pine woodlands and then by steppes in response to the climatic deterioration.
The early Pleistocene in the Guadix-Baza Basin is characterized by a sharp climatic deterioration, which possibly impeded the settlement of this region by the early hominin population from the southern Caucasus.
Based on changes in soil structure, horizons, root traces, and geochemical trends, these paleosols record a gradual change from humid, forested conditions of the late Eocene to more seasonal, semi arid, open range conditions leading up to the global climatic deterioration event of the early Oligocene at 33.2 Ma.
These models typically maintain that the reduced availability of natural resources due to climatic deterioration led to a decrease in population, both through demographic decline and actual movements of populations in the past (e.g. Kuper and Kröpelin 2006).
