Fig. 3

Megafaunal and human SPDs through time for the Southwest. Shasta ground sloth (a), mammoth (b), and human SPDs (c) are indicated in gray. The null model of exponential growth is indicated by the purple line; the purple shading denotes the 95% confidence interval around the null model (see Methods). Statistically significant deviations from the null model between 15 and 10 ka are indicated by the red (busts) and blue (booms) rugs at the base of each panel. Time series of δ¹⁸O values from the NGRIP ice core (d), CO₂ from the Dome C, Antarctica, ice core (e), and insolation seasonality (f) are provided for comparison. Data sources are in Methods