In the Mediterranean there is often no clear time gap separating an early-Holocene period of nature-dominated environmental change from a human-dominated late-Holocene one. This mid-Holocene ‘mélange’ has been the subject of debates that have often been polarised between support for climatic causation and those favouring anthropogenic explanations for changes in vegetation, river flooding, wildfire regimes, etc. One way to shed light on the causes of mid-Holocene landscape changes is to focus on natural archives, such as lake and cave isotopes, the records of which can be unambiguously attributed to climatic forcing. These primary climate proxies can then be compared and contrasted with secondary or response variables, such as pollen and microcharcoal data, which can be the product of either climate changes or human activity or both, ideally using a multiproxy approach. In addition, synthesised primary palaeoclimate data can be compared with regional-scale climate modelling simulations. Both model output and proxy data suggest an east—west division in Mediterranean climate history. They indicate that the eastern Mediterranean experienced an increase in winter-season precipitation during the early Holocene, followed by an oscillatory decline after ~6 ka BP. In western parts of the Mediterranean, early-Holocene changes in precipitation were smaller in magnitude and less coherent spatially, and maximum increases occurred during the mid Holocene, around 6—3 ka BP, before declining to present-day values. Coincident with and partly stimulated by these climatic changes, complex societies developed across the Mediterranean, particularly in eastern parts of the basin during the Bronze Age. In consequence, by the mid-first millennium BC, human-induced land cover conversion, a drier and more variable climate, and changed fire regimes combined to establish typical sclerophyllous vegetation and landscapes in the circum-Mediterranean region.

Lacustrine sedimients from Lago di Pergusa in central Sicily provide a Postglacial record of environmental change in the Mediterranean. Magnetic susceptibility measurements, lithofacies characterization and pollen analysis were carried out anid integrated to obtain a better reconstruction of the past 11000 years. The chronoogy is provided by AMS radiocarbon dates on macrofossils or bulk sediment, and by a tephra correlative with a late-Holocene explosion from the Etna volcano. The transition period related to the present interglacial reafforestation, characterized by increasing humidity, started about 10700 years BP. The onset of the wettest conditions of the Postglacial occurred at about 9000 years BP and lasted until about 7200 years BP. Then a trend towards aridification began. leading to very dry conditions at about 3000 years BP. An unquestionable human impact on vegetation is found from 2800 years BP, although earlier land use cannot be excluded. As the climate had already induced change in the vegetation, the well-known human occupancy during the last three millennia did not produce strong effects on the environment.

On the basis of a multi-proxy approach and a strategy combining lacustrine and marine records along a north–south transect, data collected in the central Mediterranean within the framework of a collaborative project have led to reconstruction of high-resolution and well-dated palaeohydrological records and to assessment of their spatial and temporal coherency. Contrasting patterns of palaeohydrological changes have been evidenced in the central Mediterranean: south (north) of around 40° N of latitude, the middle part of the Holocene was characterised by lake-level maxima (minima), during an interval dated to ca. 10 300–4500 cal BP to the south and 9000–4500 cal BP to the north. Available data suggest that these contrasting palaeohydrological patterns operated throughout the Holocene, both on millennial and centennial scales. Regarding precipitation seasonality, maximum humidity in the central Mediterranean during the middle part of the Holocene was characterised by humid winters and dry summers north of ca. 40° N, and humid winters and summers south of ca. 40° N. This may explain an apparent conflict between palaeoclimatic records depending on the proxies used for reconstruction as well as the synchronous expansion of tree species taxa with contrasting climatic requirements. In addition, south of ca. 40° N, the first millennium of the Holocene was characterised by very dry climatic conditions not only in the eastern, but also in the central- and the western Mediterranean zones as reflected by low lake levels and delayed reforestation. These results suggest that, in addition to the influence of the Nile discharge reinforced by the African monsoon, the deposition of Sapropel 1 has been favoured (1) by an increase in winter precipitation in the northern Mediterranean borderlands, and (2) by an increase in winter and summer precipitation in the southern Mediterranean area. The climate reversal following the Holocene climate optimum appears to have been punctuated by two major climate changes around 7500 and 4500 cal BP. In the central Mediterranean, the Holocene palaeohydrological changes developed in response to a combination of orbital, ice-sheet and solar forcing factors. The maximum humidity interval in the south-central Mediterranean started ca. 10 300 cal BP, in correlation with the decline (1) of the possible blocking effects of the North Atlantic anticyclone linked to maximum insolation, and/or (2) of the influence of the remnant ice sheets and fresh water forcing in the North Atlantic Ocean. In the north-central Mediterranean, the lake-level minimum interval began only around 9000 cal BP when the Fennoscandian ice sheet disappeared and a prevailing positive NAO-(North Atlantic Oscillation) type circulation developed in the North Atlantic area. The major palaeohydrological oscillation around 4500–4000 cal BP may be a non-linear response to the gradual decrease in insolation, with additional key seasonal and interhemispheric changes. On a centennial scale, the successive climatic events which punctuated the entire Holocene in the central Mediterranean coincided with cooling events associated with deglacial outbursts in the North Atlantic area and decreases in solar activity during the interval 11 700–7000 cal BP, and to a possible combination of NAO-type circulation and solar forcing since ca. 7000 cal BP onwards. Thus, regarding the centennial-scale climatic oscillations, the Mediterranean Basin appears to have been strongly linked to the North Atlantic area and affected by solar activity over the entire Holocene. In addition to model experiments, a better understanding of forcing factors and past atmospheric circulation patterns behind the Holocene palaeohydrological changes in the Mediterranean area will require further investigation to establish additional high-resolution and well-dated records in selected locations around the Mediterranean Basin and in adjacent regions. Special attention should be paid to greater precision in the reconstruction, on millennial and centennial timescales, of changes in the latitudinal location of the limit between the northern and southern palaeohydrological Mediterranean sectors, depending on (1) the intensity and/or characteristics of climatic periods/oscillations (e.g. Holocene thermal maximum versus Neoglacial, as well as, for instance, the 8.2 ka event versus the 4 ka event or the Little Ice Age); and (2) on varying geographical conditions from the western to the eastern Mediterranean areas (longitudinal gradients). Finally, on the basis of projects using strategically located study sites, there is a need to explore possible influences of other general atmospheric circulation patterns than NAO, such as the East Atlantic–West Russian or North Sea–Caspian patterns, in explaining the apparent complexity of palaeoclimatic (palaeohydrological) Holocene records from the Mediterranean area.

A mid- to late-Holocene synthesis of fire activity from the Mediterranean basin explores the linkages among fire, climate variability and seasonality through several climatic and ecological transitions. Regional fire histories were created from 36 radiocarbon-dated sedimentary charcoal records, available from the Global Charcoal Database. During the mid-Holocene ‘Thermal Maximum’ around 7500—4500 cal. BP, charcoal records from the northern Mediterranean suggest an increase in fire while records from the southern Mediterranean indicate a decrease associated with wetter-than-present summers. A North—South partition between 40° and 43°N latitude is apparent in the central and western Mediterranean. Relatively abrupt changes in fire activity are observed c. 5500—5000 cal. BP. Records of Holocene fire activity appear sensitive to both orbitally forced climate changes and shorter-lived excursions which may be related to North Atlantic cold events, possibly modulated by an NAO-like climate mechanism. In cases where human—fire interactions have been documented, the regional coherency between fire occurrence and climate forcing suggests a dominant fire—climate relationship during the early—mid Holocene. The human influence on regional fire activity became increasingly important after c. 4000—3000 cal. BP. Results also suggest that: (1) teleconnections between the Mediterranean area and other climatic regions, in particular the North Atlantic and the low latitudes monsoon areas, influenced past fire activity; (2) gradual forcing, such as changes in orbital parameters, may have triggered abrupt shifts in fire activity; (3) regional fire reconstructions contradict former notions of a gradual (mid- to late-Holocene) aridification of the entire region due to climate and/or human activities and the importance of shorter-term events; (4) Mediterranean fire activity appears hightly sensitive to climate dynamics and thus could be considerably impacted by future climate changes.

The Mediterranean region and the Levant have returned some of the clearest evidence of a climatically dry period occurring around 4200 years ago. However, some regional evidence is controversial and contradictory, and issues remain regarding timing, progression, and regional articulation of this event. In this paper, we review the evidence from selected proxies (sea-surface temperature, precipitation, and temperature reconstructed from pollen, δ¹⁸O on speleothems, and δ¹⁸O on lacustrine carbonate) over the Mediterranean Basin to infer possible regional climate patterns during the interval between 4.3 and 3.8 ka. The values and limitations of these proxies are discussed, and their potential for furnishing information on seasonality is also explored. Despite the chronological uncertainties, which are the main limitations for disentangling details of the climatic conditions, the data suggest that winter over the Mediterranean involved drier conditions, in addition to already dry summers. However, some exceptions to this prevail – where wetter conditions seem to have persisted – suggesting regional heterogeneity in climate patterns. Temperature data, even if sparse, also suggest a cooling anomaly, even if this is not uniform. The most common paradigm to interpret the precipitation regime in the Mediterranean – a North Atlantic Oscillation-like pattern – is not completely satisfactory to interpret the selected data.