Mediterranean vegetation, lake levels and palaeoclimate at the Last Glacial Maximum

Abstract

THE apparent conflict between pollen evidence for widespread Artemisia steppe1–6 (implying semi-arid conditions) and geomorphological evidence for high lake levels4,7–11 has produced controversy about the ice-age palaeoclimate of the Mediterranean region. Here we use a water-balance model12 (to predict catchment runoff) and a biome model13 (to predict vegetation type) to reconstruct the palaeoenvironment around Lake loannina—a type locality for the northern Mediterranean region. We show that both sets of evidence are compatible with a summer-dry, winter-wet regime with seasonal temperature anomalies similar to those predicted by atmospheric model simulations of the Last Glacial Maximum14–18. The drying effect of the cold North Atlantic Ocean may have been counteracted in winter by increased storm frequency under a southward-shifted jet stream, as shown by several atmospheric models16–18.