The Last Glacial Maximum and Heinrich event I on the Iberian Peninsula: A regional climate modelling study for understanding human settlement patterns

Abstract

Abstract The spatial distribution and dating of archaeological sites suggest a poor occupation of southern Iberia by hunter-gatherers after the Last Glacial Maximum (LGM) and during Heinrich event 1 (H1) compared to Northern Iberia. The H1 was a period of cold and arid climate conditions and is suspected to have played an important role in the population dynamics in Europe at the end of the Pleistocene. In this study, the potential influence of climate change on the human settlement patterns in Iberia is analysed based on regional palaeoclimate modelling. Here, the WRF model is used to simulate continuous time slices of 30 years of climate conditions representative for both the LGM and H1 at high spatial resolution. The model results indicate that, apart from a general decrease in temperature, a considerable decrease in precipitation over southern Iberia occurred during the H1, that agrees with the available climate proxy data. The analysis of ombrotypes unveils extremely arid conditions, particularly over southern Iberia and during the growing season (summer), which could have constrained the availability of food and water to the inhabitants. The total area in Iberia that can be characterized as ultrahyperarid in summer enlarged from 2% (13 K km2) during the LGM to 22% (148 K km2) during the H1. Likewise, the reconstruction of vegetation types shows an increase of non-arboreal (open shrubland, grassland) types at the expense of arboreal types in southern Iberia for H1. Thus, the different climate conditions and changes in palaeovegetation between the LGM and H1 probably played a major role in the decrease of the hunter-gatherer populations in southern Iberia.