A continuous quantitative pollen-based climate reconstruction for Lake Zeribar, Southwest Asia since Marine Isotope Stage 3

The Zagros mountains of Iran reside at a climatically sensitive convergence zone between three major atmospheric circulation systems: the mid-latitude Westerlies, the Indian Ocean Monsoon, and the Intertropical Convergence Zone. At a regional scale, variability in these systems has strongly shaped hydroclimate and human–environment interactions through time. More locally, as this mountain range exists adjacent to the Fertile Crescent, their dynamic interplay has implications for the very earliest of human civilizations. Thus, climate and ecological reconstructions help us to shed light on some of the most pressing archaeological questions, but they also help us to understand how humans have adapted to climatic change.

Lake Zeribar provides a well-established palaeoenvironmental archive for the central Zagros Mountains, with previous palynological analyses of lacustrine sediment cores spanning approximately the last 40,000 years BP. Building on this foundational work, we develop a quantitative climate reconstruction by integrating fossil pollen assemblages with a modern calibration framework. A regional climate space is constructed using open-access pollen data from the Eurasian Modern Pollen Database (EMPD2), while associated climate variables are derived from WorldClim. Fossil pollen assemblages from Lake Zeribar are then used to reconstruct mean annual precipitation and temperature, providing new quantitative constraints on past hydroclimate variability in this climatically sensitive region. While acknowledging the limitations inherent to classical pollen-climate transfer functions, this study represents a primary step in a larger climate modelling project (Swiss-French Sinergia MITRA Project) for the eastern Fertile Crescent region. The resulting reconstruction provides a benchmark against which more complex and mechanistic approaches will be evaluated.