Constraining the Deforestation History of Europe: Evaluation of Historical Land Use Scenarios with Pollen-Based Land Cover Reconstructions

TLDR

Anthropogenic land‑cover change during the preindustrial Holocene is the most significant Earth‑system transformation, affecting carbon, water, sediment cycles, biodiversity, ecosystem services, and climate, yet its quantification is hampered by wide disagreement among Holocene land‑cover scenarios. Because land‑cover change has such widespread ramifications, it is essential to assess current ALCC scenarios against observations and guide model realism. The authors systematically evaluate the KK10 and HYDE3.1 ALCC scenarios for northern and central Europe by comparing modeled land use to pollen‑derived non‑forest cover from the REVEALS reconstruction. Neither scenario perfectly matches the pollen reconstructions, but KK10 aligns well at the country scale while HYDE consistently underestimates land use over time, with discrepancies driven by per‑capita land‑use assumptions and socio‑cultural factors.

Abstract

Anthropogenic land cover change (ALCC) is the most important transformation of the Earth system that occurred in the preindustrial Holocene, with implications for carbon, water and sediment cycles, biodiversity and the provision of ecosystem services and regional and global climate. For example, anthropogenic deforestation in preindustrial Eurasia may have led to feedbacks to the climate system: both biogeophysical, regionally amplifying winter cold and summer warm temperatures, and biogeochemical, stabilizing atmospheric CO 2 concentrations and thus influencing global climate. Quantification of these effects is difficult, however, because scenarios of anthropogenic land cover change over the Holocene vary widely, with increasing disagreement back in time. Because land cover change had such widespread ramifications for the Earth system, it is essential to assess current ALCC scenarios in light of observations and provide guidance on which models are most realistic. Here, we perform a systematic evaluation of two widely-used ALCC scenarios (KK10 and HYDE3.1) in northern and part of central Europe using an independent, pollen-based reconstruction of Holocene land cover (REVEALS). Considering that ALCC in Europe primarily resulted in deforestation, we compare modeled land use with the cover of non-forest vegetation inferred from the pollen data. Though neither land cover change scenario matches the pollen-based reconstructions precisely, KK10 correlates well with REVEALS at the country scale, while HYDE systematically underestimates land use with increasing magnitude with time in the past. Discrepancies between modeled and reconstructed land use are caused by a number of factors, including assumptions of per-capita land use and socio-cultural factors that cannot be predicted on the basis of the characteristics of the physical environment, including dietary preferences, long-distance trade, the location of urban areas and social organization.