International research has analysed the impact of climate change at the end of the last glaciation

A new study led by the University of Cologne involving 25 researchers from across Europe has discovered how climate change more than 12,000 years ago affected prehistoric human populations. The research has uncovered significant changes in population size and density during key periods at the end of the last Ice Age, specifically during the Late Palaeolithic, between 14,000 and 11,600 years ago. The data on the Iberian Peninsula has been summarised by researchers from the University of the Algarve (Portugal) and the University of the Basque Country (UPV/EHU). Alvaro Arrizabalaga of the Consolidated Research Group in Prehistory is in fact the co-author of this study.

The research focused on two key periods: GI-1d-a (14,000-12,500), a climate improvement period during the late Palaeolithic, and the recent Dryas event (GS-1), a brief period of climate cooling that occurred between approximately 12,500 and 11,600 years ago, at the end of the last glaciation. The Younger Dryas event represents the last cold spell of the Pleistocene and gives way to the Holocene climate cycle, in which we still find ourselves today.

The Cologne Protocol

Using an innovative geostatistical methodology known as the Cologne Protocol and an extensive archaeological database, the researchers estimated changes in population size and density across various regional frameworks in Europe between 14,000 and 11,600 years ago.

During the first period of climate improvement (GI-1d-a), humans continued to repopulate and expand northwards and north-eastwards from central Europe, turning the region into the centre of demographic dynamics in Europe for the first time in prehistory. The populations in south-western Europe, especially on the Iberian Peninsula and in France, began to decline when compared with demographic data from previous periods.

As a result of the sudden cooling, data shows that the European population may have been fallen by up to half during the Younger Dryas. However, in some areas of central and eastern Europe, such as northern Italy, Poland and north-eastern Germany, population density increased in fact.

Demographic reaction

For researchers, this phenomenon shows how quickly prehistoric humans reacted to climate change. “Our data suggest that many human communities migrated eastwards to adapt to the new climate, rather than disappearing,” explained Isabell Schmidt of the Department of Prehistoric Archaeology at the University of Cologne who led the publication. The study highlights the fact that, unlike during the previous period of population collapse (during the Gravettian period, around 25,000 years ago), humans in the Late Palaeolithic responded by migrating to apparently more favourable areas.

The study is part of a broader line of research begun within the framework of the CRC 806 research project “Our Way to Europe” (2009–2021), which is currently continuing within the HESCOR project, funded by the Ministry of Culture and Science of the State of North Rhine-Westphalia. The UPV-EHU's contribution to the study is funded by the GIZAPRE Group (IT-1435-22) of the Basque University System and by Project PID2021-126937NB-I00 (PALEOCROSS), funded by MCIN/AEI/10. 13039/501100011033 and by “FEDER A way of making Europe”.