Solar influence on climate variability and human development during the Neolithic: evidence from a high-resolution multi-proxy record from Templevanny Lough, County Sligo, Ireland

Abstract

The relationship between climatic variations, vegetation dynamics and early human activity between c. 4150–2860 BC was reconstructed from a high-resolution pollen and geochemical record obtained from a small lake located in County Sligo, Ireland. The proxy record suggests the existence of a woodland with a largely closed canopy at the start of the fourth millennium BC. Only minor human disturbance is recorded. Following an episode of increased rainfall at c. 3990 BC, a decrease in the elm population occurred between c. 3970 and 3820 BC. This coincided with a period of warming and drying climatic conditions and an initial increase in anthropogenic activities. A second episode of high precipitation between c. 3830–3800 BC was followed by a steep increase in human impact on the landscape, which became most pronounced between c. 3740 and 3630 BC. At this time, the lake level of Templevanny Lough was at its lowest during the Neolithic.The onset of wetter and cooler conditions after c. 3670 BC, representing the transition from the Early to the Middle Neolithic, coincided with a period of woodland recovery. The Middle Neolithic was characterised by pronounced climatic oscillations including periods of substantial rainfall between c. 3600 and 3500 BC and between c. 3500 and 3460 BC. A nearly century-long climatic amelioration between c. 3460–3370 BC facilitated a revival of human activity on a small scale around the lake. Abandonment of the area and full woodland recovery occurred after a period of particularly wet and cool conditions ranging from c. 3360–3290 BC. The pollen and geochemistry data suggest that the Late Neolithic was marked by a period of ameliorated conditions between c. 3110–3050 BC that was followed by two episodes of high rainfall at c. 3060–3030 BC and c. 2940–2900 BC.The timing of the climatic shifts inferred from the Templevanny Lough record is in agreement with those of moisture/precipitation and temperature reconstructions from northern and western Europe and the Alps, suggesting that the studied period was characterised by a high-frequency climate variability. The results of the present study imply that human development during the Irish Neolithic was influenced by climatic variations. These climatic shifts correspond to variations in solar activity, suggesting a solar forcing on climate.