Human-triggered magnification of erosion rates in European Alps since the Bronze Age

• Published in: Nature communications Vol. 15; no. 1; p. 1246
• Main Authors: Rapuc, William, Giguet-Covex, Charline, Bouchez, Julien, Sabatier, Pierre, Gaillardet, Jérôme, Jacq, Kévin, Genuite, Kim, Poulenard, Jérôme, Messager, Erwan, Arnaud, Fabien
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 10.02.2024; Nature Publishing Group; Nature Portfolio
• Subjects: 140/146; 140/58; 704/172/4081; 704/2151/209; 704/2151/215; Anthropocene; Bronze Age; Climate effects; Environment and Society; Environmental Sciences; Erosion rates; Geochemistry; Global Changes; Habitability; High altitude; Human influences; Humanities and Social Sciences; Lake sediments; Lakes; Middle Ages; Mountain regions; Mountainous areas; multidisciplinary; Pastoralism; Regional development; Science; Science (multidisciplinary); Soil erosion; Alps; Lake sediment, Geochemistry, Erosion, Human impact, Alps
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-45123-3

A major feature of the Anthropocene is the drastic increase in global soil erosion. Soil erosion is threatening Earth habitability not only as soils are an essential component of the Earth system but also because societies depend on soils. However, proper quantification of the impact of human activities on erosion over thousands of years is still lacking. This is particularly crucial in mountainous areas, where the highest erosion rates are recorded. Here we use the Lake Bourget catchment, one of the largest in the European Alps, to estimate quantitatively the impact of human activities on erosion. Based on a multi-proxy, source-to-sink approach relying on isotopic geochemistry, we discriminate the effects of climate fluctuations from those of human activities on erosion over the last 10,000 years. We demonstrate that until 3800 years ago, climate is the only driver of erosion. From that time on, climate alone cannot explain the measured rates of erosion. Thanks to an unprecedented regional paleoenvironmental reconstruction, we highlight that the development of pastoralism at high altitudes from the Bronze Age onwards and the extension of agriculture starting in the Middle Ages were key factors in the drastic increase in erosion observed in the Alps. Using a lake sediment core taken from the European Alps and combining a source-sink approach with isotope geochemistry, it has been established that the effects of human activities have outweighed those of climate on erosion for more than 3800 years.