Around 1800 BC: warm peak (start of ‘Second Intermediate Period’ in Egypt).Around 1900 BC: cold peak (‘Early Neoglacial Anomaly’, ENA) (migration of the Harappa-Indus Valley civilisation).Around 2200 BC: warm peak with severe drought (initiation of Minoan civilisation, start of First Intermediate Period in Egypt).Around 2900 BC: cold peak (‘Piora Cold Period’).Around 3000 BC: warm peak (initiation of Egyptian and Sumerian civilisations).Around 3300 BC: warm peak (initiation of Harappa-Indus Valley civilisation).Around 6000 BC: warm peak (‘Holocene Thermal Maximum’).Around 6200 BC: cold peak: ‘8200 BP Cold Period’.The main Holocene warm and cold periods are listed very schematically as follows : This is perhaps showing some astronomical influence? A quick look at the intervals between the warm peaks shows that they are fairly equidistant with an average of ca. The temperature variations between warm and cold peaks are in the order of 1☌, except for the ‘8200 BP event’ where it is around 2☌. It can be noted that the drop of temperature between this maximum and the 20 th c. The so-called ‘Holocene Climatic Optimum’ (7000-4000 BC) is clearly visible with a thermal maximum around 6000 BC. Civilisation changes and Climate changesīased on Greenland reconstructed paleotemperatures from six ice cores,

Let’s look at the temperature variations of surface ice in Greenland (deduced from ice cores) which is assimilated with temperatures in the European area and possibly in the whole Mediterranean area, and let’s compare it with the initiation of the major civilisations. Coring is often used to extract the proxies. Proxies are found in lake sediment, marine sediment, peat bogs, ice, speleothems, tree rings and coral skeleton rings. The most common climate proxies are gas bubbles, pollens, dinocysts, isotopes, the quantities of which tell us something about past climate conditions. They provide the only means for scientists to determine climatic patterns before record-keeping began (around 1880) ( Wikipedia). So-called ‘climate proxies’ (indicators) are preserved physical characteristics of the past that stand in for direct meteorological measurements and enable scientists to reconstruct the climatic conditions.

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