Winter hydroclimate contrasts between southern and northern Europe at ∼ 5.2 ka

Winter climate variations in midlatitude regions have far-reaching effects on both natural and human systems worldwide. However, most climate reconstructions focus on either annual or summer climate conditions. Here we present a stalagmite stable isotope record from Ursilor Cave (Romania) where the delta O-18 values are controlled by winter temperature. Because of its East-Central Europe (ECE) location, the cave site is well suited to capture variations in precipitation and temperature in response to changes in the North Atlantic region. Present day precipitation and temperature in this region are controlled by two teleconnection patterns, the Arctic Oscillation (AO) and the East Atlantic (EA). By analyzing composite maps for four different scenarios of AO and EA phase, we suggest that between 5.6 and 5.2 ka the positive phases of AO and EA became increasingly dominant. This shift led to generally warmer winters in northern Europe, but drier conditions in southern Europe and the Levant. Considering the compound effect of AO and EA on the hydroclimate of ECE, our study highlights the importance of examining the combined impact of teleconnection patterns on climate proxies influenced by various forcing mechanisms.

Automated summary

Winter climate variations have significant effects on both natural and human systems worldwide. A new study in Romania reveals that winter temperature variations control the stable isotope record in a stalagmite, thereby influencing precipitation and temperature changes in East-Central Europe. The study also highlights the importance of considering teleconnection patterns in understanding the combined impact of various forcing mechanisms on climate proxies.