The Balkan peninsula

The Mediterranean climate in the Balkan Peninsula is limited to the coastal area and the island region. On the Adriatic coast, the average winter temperature is moderate, except for the northern region where continental cold air is introduced by the Bora wind. In July, the average temperature is 23-25 °C because of maritime influences. In the coastal area, precipitation is heavy. For instance, some places in Yugoslavia receive more than 4000 mm of rain annually. On the western mountain slopes and in low-lying areas, annual precipitation is much less (500-600 mm). In the southern areas, the Mediterranean climate is much more pronounced, with lower precipitation and higher temperatures (for example, Athens never receives more than 400 mm of precipitation annually). The average July temperature in Athens is 27-28 °C, while in January it is 7-8 °C.

The climate on the southern Aegean coast tends toward the continental, with comparatively lower precipitation. In the Aegean islands, the climate is relatively dry, while the climate of the Ionian Sea is more hot and humid.

Paepe and co-workers investigated the effect of changing climate during the Quaternary on landscape and soil profiles in Greece (Paepe, 1984) and claim that there is a periodic cyclicity in the rate of sedimentation. In the Marathon Plain, six Holocene soils were described separated by alluvial deposits. The earliest, Marathon Soil (HS1), most probably developed about 7 ka BP and the last, Kallileios Soil (HS6), is dated 725 ± 5 BC. In the latter soil, geometrical tombs were located. The in-between layers, HS3, HS4 and HS5, together with relevant fluvial gravel deposits, correlated with the three phases of the Helladic period. Soil formations in the fluviatile valley system tally perfectly with peat development in the marine sequence of Marathon. Furthermore, between soil development phases, fluviatile sedimentation rates score the highest values (Fig. 2.2).

Paepe (1984) interpreted the soil layers as indicating warmperiods, while pluvio-alluvial periods are cold. Comparing the section of Marathon with the paleo-climate columnar section of the

Levant (Fig. 2.2), I would suggest that the cold wet periods would be characterized by rather small sedimentation rates, because the forest expands and there is less soil erosion, while during dry periods, higher rates of soil erosion would cause higher sedimentation rates. This would better explain the correlation of soil formation periods with periods of profusion of settlements.

Of special interest is the observation that, towards the close of the third millennium BC (as determined by pottery finds), heavy destruction is visible over large areas of Greece: "Settlements which were, for their time, rich and powerful, and which had a long history of stability and continuity, literally came tumbling down" (Finley, 1981, p. 13). This period can be correlated with a peak in the deposition rates of pluvial material in the Marathon Plain and, thus, with the warm arid period at the transition from the EB to the MB period in the Levant.

In general, the Marathon Plain sedimentation rates can be correlated with the proxy-data time series of the Levant in the following manner.

During the Neolithic, the Pleistocene forest still dominated the area, protecting the soil cover. Towards the Upper Neolithic, the rates of sedimentation became higher as a result of warming of the climate. The rates fell again towards the Chalcolithic and EB but rose towards the MB. The Iron Age was again characterized

Fig. 2.1. Map of Europe.
Fig. 2.2. Paleo-hydrology of Greece and Italy.

by low sedimentation, that is, a cold climate. During the Roman period, the rates are high in general, presumably because of deforestation, but one can still see fluctuations that correspond to cooling and warming. During the Moslem-Arab warm spell (c. 700 AD), rates of sedimentation became higher, corresponding to the phase of global warming.

The soil grain size median calculated by Harrison et al. (1993), who processed published data on lake levels in Greece, indicates an increase in all lake levels throughout the early Holocene, to a maximum between 7.5ka and 5.5kaBP with a minimum c. 4.5 kaBP. Then there was a return to wetter conditions around 3.0 ka BP, after which there was a general decrease in the levels of the lakes. Comparing these data with the time series of the Levant, the high levels of the lakes in Greece, from 7.5 ka to 5.5 ka BP, may correlate with the cold mid-Neolithic period around 7.5 ka BP and the cold humid climate of the Chalcolithic (c. 5.3 ka to 6.5 kaBP). The warm dry period, with low lake levels in Greece, c. 4.5 kaBP may be correlated with the dry warm period of the MB in the Levant, which started c. 4.3 kaBP. Yet, neither the cold wet phase of the EB of the Levant (between c. 5.2ka and c. 4.3 kaBP) nor the changes observed in the Levant after 2.5 kaBP is observed in the Greek lake levels.

A pronounced stage of destruction and desertion all over Greece, for which archaeologists have found evidence and which caused the collapse of the Mycenaean civilization, occurred c. 3.2kaBP. Yet archaeologists are divided with regard to the reasons for this collapse. Finley (1981, p. 58) tends to connect it with the invasion of Indo-Arian tribes from the north, while Weiss (1982) claims that there is no evidence of newcomers at that time. Also, Carpenter (1966, p. 37) claimed that "These sites were deserted without any trace of destruction or conflagration" and suggested that the destruction of the settlements was a result of severe droughts, which were followed by the migration of the Aegean inhabitants of mainland Greece to the west, north, and east to seek refuge: the Sea People to the Levantine coast and Egypt, the Semitic tribes (the Apiru) to Canaan, and the Hittites to northern Syria below the Taurus mountain rampart. The correlation with the Levant time series supports the climate change explanation for this disaster.

Carpenter (1966) offered a similar argument concerning archaeological evidence of the desertion of many Greek sites in the Peloponnese during the seventh and eighth century AD. He argued against the explanation proposed by some archaeologists that these sites were vacated because of the invasion of Greece by Slavic tribes. According to Carpenter, the Slavs did not reach Greece until two or three centuries later and the exodus of people from their homes was the result of the severely destructive drought, which ended in the ninth century AD, after which "southern Greece was once more fit to support an increasing population" (Carpenter, 1966, p. 79) The time series from the Levant supports this explanation.

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