Fig. 3. Results of Earth system model data assimilation.

The right hand panels also account for organic carbon burial during PETM recovery. (a,i) Atmospheric pCO₂ (red, LH axis) and mean global SST (blue, RH axis). (b,j) Modelled mean global ocean surface pH (observed smoothed surface ocean pH data as yellow symbols). (c,k) Model diagnosed rates of CO₂ release (red) and excess CO₂ consumption due to silicate weathering (green) from PETM onset onwards. (d,l) Cumulative CO₂ release (red) and organic carbon burial (blue). (e,m) Modelled mean global ocean surface δ¹³C (observations as yellow symbols). (f,n) Model diagnosed δ¹³C of the CO₂ release (red) and isotopic composition of buried carbon (blue). Shaded bands (a,b,e,i,j,m) and empty bars (c,d,f,k,l,n) reflect 95% uncertainty limits. Bars reflect 2 kyr averaging (c,f,k,n) or integration (d,l) bins. All model results and related data are plotted from -50 to +150 kyr relative to the onset of the CIE, on our preferred orbital age model²⁵.