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

THE apparent conflict between pollen evidence for widespread Artemisia steppe^1-6 (implying semi-arid conditions) and geomorphological evidence for high lake levels^4,7-11 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 Maximum^14-18. 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 models ^16-18.