Fig. 4: Comparison between ice core δ¹⁸O data and ice sheet model simulation.

a, Surface elevation (blue solid line) and bedrock elevation (blue dashed line) simulated using the PISM model¹² and surface elevation calculated using SIR δ¹⁸O (pink) with 250-year box smoothing. The shading represents the range when using slopes of 0.8 ± 0.2‰ per 100 m as the conversion from δ¹⁸O to elevation. b, Rate of surface elevation change determined using PISM model (blue shading) and SIR δ¹⁸O (pink shading). The pink dashed lines show the rate calculated using the range of δ¹⁸O to elevation slopes. c, Grounding line (solid line) and ice shelf edge (dashed line) simulated using PISM model. Ice core data are plotted using the SIR age scale (top axis) and model results are plotted on the model timescale (bottom axis). The grey bar is the early Holocene transition, and the black dashed line is the inflection point of the transition.