Layer Q5S 230 at Franchthi, a cave and shoreline settlement in Greece’s Peloponnese, supplied 17 limpet shells to a new climate study, and four of them record almost the same sea temperatures. The text doesn’t assign the layer a period, but only the Early Neolithic (6600 to 5800 cal BCE, calibrated radiocarbon years) has room for it in Table 1. People ate these limpets, and the authors allow that some were alive in the same years.
The study depends on how many separate winters those shells can vouch for, and its target is a familiar belief: that the spread of farming in Europe stalled in Greece from about 6600 to 6000 cal BCE because bitter, unpredictable winters made new settlements too risky.
Niklas Hausmann and Danai Theodoraki of the Leibniz-Zentrum für Archäologie (LEIZA) in Mainz report in PNAS1 that they can’t find those winters at Franchthi. Across 121 limpet shells (Patella sp.), Early Neolithic winters show no cooling of the proposed size, and sea temperature has no significant statistical link to the animals people were eating, layer by layer. I think the first result is sturdier than the second, and neither reaches as far as the paper’s title, which says the Neolithic expansion is decoupled from climate instability.
The stall ended fast. Between 6000 and 5600 cal BCE, farmers settled coasts from Greece to southern Spain, part of an expansion the paper clocks at over 400 km per generation. Two climate episodes have been offered as the brake: the Rapid Climate Change (RCC) interval, 6600 to 6000 cal BCE, and the colder, drier 8.2 BP event at its end (8200 to 8000 cal BP, or 6200 to 6000 cal BCE). A model by Rohling and colleagues (2019) estimates three to five extreme cold events a year during the RCC, and pollen records put winter cooling during the 8.2 BP event at 2 °C in Aegean marine cores (Kotthoff et al. 2008) and more than 4 °C in an eastern Macedonian lake core (Pross et al. 2009). None of those records comes from an archaeological site, which is the gap this study tries to close.
