Detecting Climate Transitions with Recurrence Plots: A Case Study of the Younger Dryas

Identifying regime shifts in paleoclimate proxy records remains challenging when time series are short and irregularly sampled. Such characteristics are common in paleoclimate archives and often limit the applicability of traditional linear statistical methods for quantifying regime transitions. In this study, we focus on the Younger Dryas event using a unique, biomarker stable isotope-based paleoclimate proxy dataset derived from two distinct lake sediment records that were hydrologically connected in the paleoenvironment. The proxy signals from both sediment cores exhibit strong similarities but also notable differences. We therefore use them as a ‘replicate’ sample, providing a natural framework for comparative analysis.

Recurrence plots and recurrence quantification analysis are employed to characterize nonlinear variability and to compare structural patterns between the two records. The recurrence plots capture the overall temporal extent of the Younger Dryas event in both proxies, while revealing small offsets in its onset and termination. These differences suggest potential influence of local environmental conditions on the lake systems and provide additional insights into site-specific responses. By analyzing the residual differences between the two proxy records, smaller-scale features can be identified, potentially reflecting local processes hidden by the large-scale climatic signal.