Climate Niche Modeling Reveals the Fate of Pioneering Late Pleistocene Populations in Northern Europe

Following deglaciation during the final stages of the Pleistocene, vast landscapes became increasingly accessible for human dispersal. With no historical analogs, it remains uncertain how people were adapting to these unknown and often unstable environments and whether dispersals were sustained or characterized by local retreat or extinction events. We here address these uncertainties by using climate niche modeling to investigate the relationship between climate and the archaeological record of such a dispersal event: the Late Upper Paleolithic Hamburgian settlement of northern Europe. Our models consider temperature and precipitation from paleoclimate models with high temporal and spatial resolution. They suggest that rising temperatures instead of precipitation changes drove dispersal events by allowing carriers of the Hamburgian tradition to occupy a specific northward-shifting climate space. Similarly, our models suggest a subsequent constriction and fragmentation of this climate space caused by declining temperatures. This climatic downturn and shifting climate space coincide with the disappearance of the Hamburgian tradition from the archaeological record. We argue that this sudden climatic change altered the social and demographic costs of northward dispersal to become unsustainable, leading to a depopulation of the region.