Fig. 3: Area-weighted average of site-level climate excursion frequency through the Holocene.

At each site, parametric uncertainty is considered, and the fraction of detected excursions for both directions in (a) temperature, and (b) hydroclimate range from 0 to 1. The occurrence and significance of (c) combined warm/wet and cold/dry excursions is shown as the product of wet/warm and cold/dry excursion frequency. Each bar shows the area- and uncertainty-weighted proportion of records with excursions in 400 ± 100 year windows. The axes for cold, dry, and cold/dry excursions are inverted. The excursion detection analysis is repeated in 200-year intervals across the Holocene. Colored lines show the 95% confidence interval (cl) based on null hypothesis testing. Due to test multiplicity however, we expect some apparently significant results to occur due to chance alone. Cross-hatched and single-hatched bars indicate intervals that remain significant at the 0.05 and 0.10 levels, respectively, after using a modified Holm–Bonferroni correction. See text for details.