Fig. 4

Simulated impacts of sea level triggered coastal erosion and related permafrost thawing on atmospheric carbon reservoirs using the global carbon cycle model BICYCLE. a Assumed carbon release from permafrost thaw of 85 PgC from 18 to 10.8 kyrs BP, either gradual (orange) or in 3 short periods of 200 yr duration connected with rapid sea level rise (red). For comparison our new MAR data and a reconstruction of sea level change¹⁴ are also shown. b Simulated anomalies in atmospheric CO₂ levels for the two carbon release scenarios and reconstructed CO₂ data (mean ± 1σ) from ice cores^{12, 13} for comparison (data as in ref. ⁶⁹). c Simulated anomalies in atmospheric ∆¹⁴C. The unexplained residual (mean (blue) ± 1σ uncertainty (grey)) shows ∆(∆¹⁴C) that is not explained by changes in ¹⁴C production rate. Anomalies in ∆¹⁴C caused by the two carbon release scenarios with difference in the pre-depositional ages of the released carbon (5 kyrs: broken lines; 10 kyrs: solid lines). IntCal13¹¹ atmospheric ∆¹⁴C for comparison