No abstract

Subfossil pollen and plant macrofossil data derived from 14 C-dated sediment profiles can provide quantitative information on glacial and interglacial climates. The data allow climate variables related to growingseason warmth, winter cold, and plant-available moisture to be reconstructed. 123Clim Dyn (2011) 37:775-802 DOI 10.1007 surface-pollen assemblages are shown to be accurate and unbiased. Reconstructed LGM and MH climate anomaly patterns are coherent, consistent between variables, and robust with respect to the choice of technique. They support a conceptual model of the controls of Late Quaternary climate change whereby the first-order effects of orbital variations and greenhouse forcing on the seasonal cycle of temperature are predictably modified by responses of the atmospheric circulation and surface energy balance.

In the Mediterranean Basin, recent accelerated changes in the environment (climate, land use, pollution, biodiversity loss) have caused loss of life and damages to infrastructure and ecosystems. The future presents unprecedented risks for human well-being, socioeconomic development, ecosystems and biodiversity. Policies for sustainable development need to aim for the mitigation of these risks but lack adequate information about the rates of environmental change and the combined risk they present to human society. For five interconnected impact domains (water, ecosystems, food, health and security), trends and scenarios point to significant risks during coming decades. More observations and better impact models exist for the Northern Mediterranean shores than for the South. This important bias is exacerbated by the large difference in financial resources available for adaptation and the development of resilience between north and south. A dedicated effort to synthesize existing scientific knowledge from all relevant disciplines is now underway to provide better understanding of the risks posed. In the Mediterranean Basin, human society and the natural environment have co-evolved over several millennia with significant climatic variations, laying the ground for diverse and culturally rich communities. The region lies in a transition zone between mid-latitude and subtropical circulation regimes. It is characterized by a complex morphology of mountain chains and strong land-sea contrasts, dense and growing human population and various environmental pressures. Observed rates of climate change in the Mediterranean Basin exceed global trends for most variables. Annual mean temperatures are now 1.4 °C above late nineteenth century levels (Figure 1), notably during the summer months. Heat waves occur more frequently, and the frequency and intensity of droughts have increased since 1950. 1,2,3 For each of the most recent decades, the surface of the Mediterranean Sea has warmed by around 0.4 °C. 4 During the period 1945-2000, sea-level has risen at a rate of 0.7±0.2 mm yr-1 , 5 accelerating to 1.1 mm yr-1 for the period 1970-2006. 6 During the last two decades, sea-level has been estimated to rise by about 3 cm decade-1 , 7 in part due to