Fig. 4: Carbon sequestration potential if mangrove afforestation and reforestation projects are implemented globally over a 40-year period.

a–d Changes in carbon density among pools over time during mangrove reforestation and afforestation. a Aboveground biomass carbon (AGC) pool (n = 167 for reforestation, n = 138 for afforestation); b Belowground biomass carbon (BGC) pool (n = 129 for reforestation, n = 124 for afforestation); c Sediment carbon (SCS) pool (n = 50 for reforestation, n = 108 for afforestation); and d Total ecosystem carbon (TECS) pool (n = 28 for reforestation, n = 63 for afforestation). Fitted lines and ribbons are calculated as the predicted values and the 95% confidence intervals for the 2.5th and 97.5th percentiles based on nonlinear models. e Country-specific maximum carbon mitigation potential from mangrove reforestation over 40 years (2021–2060) under the 1-year-completed restoration scenario, with the density of shading representing the maximum carbon mitigation potential of each country. Countries in gray had no mangrove loss to deforestation between 1996 and 2016, or no mangroves. The inset graph represents the global maximum carbon mitigation potential by reforestation and assuming the same area for redeeming afforestation. Error bars represent a 95% confidence interval for maximum carbon mitigation potential in each carbon pool.