The 4.2 ka BP Event in the Mediterranean region: an overview

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, 18O
on speleothems, and 18O 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.

Monica Bini and Giovanni Zanchetta are
indebted to the University of Pisa and Earth Science Department
for the support in organizing the workshop “The 4.2 ka BP Event”.
Monica Bini and Giovanni Zanchetta’s contribution have also been
developed within the frame of the project “Climate and alluvial
event in Versilia: integration of Geoarcheological, Geomorphological,
Geochemical data and numerical simulations” awarded to Monica
Bini and funded by the Fondazione Cassa di Risparmio di Lucca.
Leszek Marks and Fabian Welc were funded by the National Science
Centre in Poland (decision no. DEC-2013/09/B/ST10/02040).
Aurel Per¸soiu was funded by UEFISCDI Romania, trough grant no.
PN-III-P1-1.1-TE-2016-2210.