Fig. 1: Sea levels and atmospheric CO₂ during the past 800 kyr.

a, RSL (blue)¹ and CO₂ (brown, purple)^16,17. Age scales offset by 2 kyr (CO₂ leads). Fossil original CO₂ data^16,17 resampled to 1 kyr (brown line) and smoothed (11 kyr running average; brown and purple symbols). CO₂ from periods with RSL < −90 m (dashed brown line) are highlighted (purple). The modern data (red) are neither resampled nor smoothed. b, Correlation (orange line) between RSL and fossil CO₂ data when RSL > −90 m (brown). Excluded data pairs are purple. The correlation with a slope of 1 m ppmv⁻¹ and an offset of −280 m (orange line) has an R² of 0.7.