Fig 1.
Carbon fluxes (sequestration and emissions) associated with coastal habitats and habitat changes due to sea level rise.
Table 1.
Data and model variations tested in the sensitivity analysis.
Fig 2.
Baseline (no SLR) and primary model projection projected coastal habitat (1.2 m of sea level rise by 2104) in the study area.
See Fig A-F in S2 Text for state-level diagrams.
Fig 3.
Spatial distribution of (a) projected coastal marsh loss given 1.2 m SLR through 2104, (b) projected forest conversion to coastal marsh, including both wetland and upland forests, given 1.2 m SLR through 2104, and (c) projected migrated marsh present in 2104, given 1.2 m SLR. Made with Natural Earth (http://www.naturalearthdata.com/about/terms-of-use/).
Fig 4.
Projected coastal marsh changes over time across six eastern states for the primary model projection.
The large, low-elevation coastal plain provides an extensive area for inland marsh migration during the first half of the century, but additional sea level rise causes the loss of migrated marsh after 2050. Error bars represent the minimum and maximum projected area of each habitat type in 2104 among the model variations included in the sensitivity analysis.
Table 2.
Percentage of existing coastal marshes in the study area by their suspended sediment concentration and tidal range.
Most marshes are in areas with low sediment availability and low tidal range, which limits their potential rates of sediment accretion and thus their ability to keep up with sea level rise.
Fig 5.
Net carbon fluxes—carbon sequestration (negative) and emissions (positive) for the study area (including the original extent of seagrass and coastal marsh plus transition zone) through 2124, comparing no sea level rise with projected habitat changes due to 1.2-meter sea level rise by 2104.
Black points represent total net carbon flux (emissions minus sequestration); error bars are the maximum and minimum projected carbon fluxes among the variations included in the sensitivity analysis (see section 4.2.1 for details). For state-level results, see Fig G-L in S2 Text.
Fig 6.
Annual carbon flux (MMT CO2e/year) sequestered (negative) or emitted (positive) by the study area over time for primary model projection, as habitats change due to sea level rise.
See Fig G-L in S2 Text for state-specific results.
Fig 7.
Additional net carbon emissions due to SLR (difference between net C flux with SLR and net C flux without SLR), MMT CO2e, 2010–2124.
Results for the variations tested in the sensitivity analysis are shown in blue bars; the results from the primary model projection are shown in an orange bar for comparison.
Fig 8.
Sensitivity analysis of modeled net carbon flux with SLR to input parameters and assumptions (blue bars), at the regional scale (totals across all states in the study area), compared to the primary model projection results (orange bar). Percent changes in the variation descriptions (e.g., Salinity +20%) are relative to the parameters used in the primary model projection. State-level results available in supplementary materials (Table G in S2 Text).