Radiocarbon (¹⁴C) is decaying over time, which is used to determine the age of carbon-containing objects. Calibration curves are necessary to come from measured ¹⁴C values to calendar ages. We use different models in order to improve future calibration curves, especially around times of abrupt changes in the Atlantic meridional overturning circulation. We find that uncertainties during those times are underrepresented in present calibrations, especially in the Atlantic.

New high-resolution pollen data and pollen-inferred climatic reconstructions from the Alboran Sea reveal rapid climate oscillations during Marine Isotope Stage 6 (187–130 ka BP) in the southwestern Mediterranean. Three main phases show shifts from cool-humid to cold-arid and then wetter conditions, with Heinrich Stadial 11 marking severe cooling and steppe expansion. Neanderthals persisted regionally, though HS11 may have contributed to population decline and the end of the Lower Palaeolithic.

Palaeoecology provides crucial information into past changes in climate and ecosystems. However, uncertainties from environmental processes and laboratory methods affect our inferences from the data. We use a virtual ecological approach to quantifying uncertainties by simulating proxy data and systematically introducing sources of uncertainty. Better understanding the effects of uncertainty can help shape study designs before a project is carried out and make robust inferences palaeoproxy data.