Fig 1.
Schematic representation of the RothC model.
Depicts the required input data and structure of SOC pools in the model. Adapted from the RothC manual [13]. This figure was previously printed in [4].
Fig 2.
Data processing and model structure flowchart.
Red box shows new steps to incorporate climate change projections.
Fig 3.
Mean Vermont temperature from GCM projections.
Shows average of the four GCMs, using a ten-year rolling mean to better visualize the overall trend. Gray area is the standard deviation between GCMs. Red vertical line indicates the beginning of the simulation (Jan. 2022). After this point, the GCMs’ temperature projections show similar trends, but increasingly diverge.
Fig 4.
Projected SOC stock change on all Vermont farmland in four future years.
Compares a static climate normal assumption against a climate change assumption based on four alternative GCMs. Shows the mean difference in SOC averaged across all four GCMs compared to the 2022 baseline of around 22.7 Mt total SOC in the study area, with standard deviation between GCMs indicated by the error bars.
Fig 5.
SOC stock change on all Vermont farmland, with projected average temperature.
Colored lines show mean SOC stock change from 2022 baseline, and shaded regions indicate standard deviation across the four GCMs. Black line shows projected one-year rolling-mean average temperature for all GCMs (in °C, referenced to the right y axis), with shaded region indicating standard deviation across GCMs. Dashed red line indicates start of simulation (Jan. 2022).
Fig 6.
Projected SOC stock change in each Ecoregion, 50 years after land use transition.
Color indicates SOC stock change from the 2022 baseline to 2072 (in t/Ha). Top row shows RothC simulation results assuming continued 1991–2021 climate normal, and bottom row shows results with climate change projections under RCP 4.5 averaged across GCMs. Columns correspond to land management scenarios. Shapefile, metadata, and terms of use for Vermont boundaries can be found at [38], and Ecoregions at [39].