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During the period of instrumental records, the North Atlantic Oscillation (NAO) has strongly influenced interannual precipitation variations in the western Mediterranean, while some eastern parts of the basin have shown an anti-phase relationship in precipitation and atmospheric pressure. Here we explore how the NAO and other atmospheric circulation modes operated over the longer timescales of the Medieval Climate Anomaly (MCA) and Little Ice Age (LIA). High-resolution palaeolimnological evidence from opposite ends of the Mediterranean basin, supplemented by other palaeoclimate data, is used to track shifts in regional hydro-climatic conditions. Multiple geochemical, sedimentological, isotopic and palaeoecological proxies from Estanya and Montcortés lakes in northeast Spain and Nar lake in central Turkey have been crosscorrelated at decadal time intervals since AD 900. These dryland lakes capture sensitively changes in precipitation/evaporation (P/E) balance by adjustments in water level and salinity, and are especially valuable for reconstructing variability over decadal-centennial timescales. Iberian lakes show lower water levels and higher salinities during the 11th to 13th centuries synchronous with the MCA and generally more humid conditions during the 'LIA' (15th-19th centuries). This pattern is also clearly evident in tree-ring records from Morocco and from marine cores in the western Mediterranean Sea. In the eastern Mediterranean, palaeoclimatic records from Turkey, Greece and the Levant show generally drier hydro-climatic conditions during the LIA and a wetter phase during the MCA. This implies that a bipolar climate see-saw has operated in the Mediterranean for the last 1100 years. However, while western Mediterranean aridity appears consistent with persistent positive NAO state during the MCA, the pattern is less clear in the eastern Mediterranean. Here the strongest evidence for higher winter season precipitation during the MCA comes from central Turkey in the northeastern sector of the Mediterranean basin. This in turn implies that the LIA/MCA hydroclimatic pattern in the Mediterranean was determined by a combination of different climate modes along with major physical geographical controls, and not by NAO forcing alone, or that the character of the NAO and its teleconnections have been non-stationary.

The multi-proxy analysis of sediment cores recovered in karstic Lake Estanya (42°02' N, 0°32' E; 670 m a. s. l., NE Spain), located in the transitional area between the humid Pyrenees and the semi-arid Central Ebro Basin, provides the first high-resolution, continuous sedimentary record in the region, extending back the last 21 000 years. The integration of sedimentary facies, elemental and isotopical geochemistry and biogenic silica, together with a robust age model based on 17 AMS radiocarbon dates, enables precise reconstruction of the main hydrological and environmental changes in the region during the last deglaciation. Arid conditions, represented by shallow lake levels, predominantly saline waters and reduced organic productivity occurred throughout the Last Glacial Maximum (21-18 cal kyrs BP) and the late glacial, reaching their maximum intensity during the period 18-14.5 cal kyrs BP (including Heinrich event 1) and the Younger Dryas (12.9-11.6 cal kyrs BP). Less saline conditions characterized the 14.5-12.6 cal kyrs BP period, suggesting higher effective moisture during the Bölling/Allerød. The onset of more humid conditions started at 9.4 cal kyrs, indicating a delayed hydrological response to the onset of the Holocene which is also documented in several sites of the Mediterranean Basin. Higher, although fluctuating, Holocene lake levels were punctuated by a mid Holocene arid period between 4.8 and 4.0 cal kyrs BP. A major lake-level rise occurred at 1.2 cal kyrs BP, conducive to the establishment of conditions similar to the present and interrupted by a last major water level drop, occurring around 800 cal yrs BP, which coincides with the Medieval Climate Anomaly. The main hydrological stages in Lake Estanya are in phase with most Western Mediterranean and North Atlantic continental and marine records, but our results also show similarities with other Iberian and northern African reconstructions, emphasizing peculiarities of palaeohydrological evolution of the Iberian Peninsula during the last deglaciation.

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This paper reports the vegetation changes of the last millennium, as deduced from palynological analysis of a sediment core from lake Montcortès, situated around 1000 m elevation in the southern pre-Pyrenean flank. The record begins in the Middle Ages (~AD 800) and ends around AD1920, with an average resolution of about 30 years. The reconstructed vegetation sequence is complex and shows the influence of both climate and human activities in the shaping of landscape. Prefeudal times were characterized by the presence of well-developed conifer forests, which were intensely burnt at the beginning of the feudalism (AD 1000) and were replaced by cereal (rye) and hemp cultivation, as well as meadows and pastures. In the 13th century, a relatively short warming likely corresponding to the Medieval Warm Period (MWP) was inferred by the presence of a low Mediterranean scrub community today restricted below 800 m elevation. This community disappeared during the Little Ice Age (LIA) cooling in the 15th century, coinciding with a decline in human activities around the lake. Forest recovery began around AD 1500, at the beginning of the Modern period, coinciding with wetter climates. However, forests retreated again during the 17th century coinciding with a maximum in olive and hemp cultivation. This situation was reverted in post-Modern times (19th century), charactrized by an intense agricultural crisis and a significant decline of population that favored forest re-expansion. Correlations with the nearby Estanya lake, situated about 350 m below, provided a more regional picture. Besides some climatic forcing evident in both sequences, human activities seem to have the main drivers of landscape and vegetation change in the southern Pyrenean flank, in agreement with similar conclusions from other studies developed on high-mountain environments.