Global Evaluation of Terrestrial Biogeochemistry in the Energy Exascale Earth System Model (E3SM)
One of the major uncertainties for the prediction of the future net land–atmosphere carbon exchange relates to the representation of terrestrial biogeochemical cycles in Earth system models. This study provided a systematic evaluation of C, nitrogen (N) and phosphorus (P) cycling dynamics in the Energy Exascale Earth system Model (E3SM) on the global scale using both observational and experimental data. This study further quantified the role of P cycle dynamics and P limitation in affecting simulated C sources and sinks globally.
These results show that E3SM provides a reasonable representation of contemporary global-scale C, N, and P cycling dynamics. This study also demonstrates that the introduction of P cycle dynamics and C–N–P coupling have substantial consequences for projections of future C uptake. This study further highlights the data needs for global land model evaluation, particularly the need for more synthesis datasets on nutrient pools and fluxes.
Terrestrial ecosystems play important roles in taking up anthropogenic CO2 emissions. One of the major uncertainties for the prediction of the future net land–atmosphere carbon exchange relates to the representation of nutrient cycling and carbon-nutrient interactions in models. Here we evaluated the performance of land model in E3SM that includes both nitrogen (N) and phosphorus (P) limitation on carbon cycle processes. We show that the land model in E3SM provides a reasonable representation of contemporary global-scale C, N, and P cycling dynamics. We show that global C sources and sinks are significantly affected by P limitation. Our study suggests that the introduction of P limitation in land surface models is likely to have substantial consequences for projections of future carbon uptake. This study further highlights the data needs for global land model evaluation, particularly the need for more synthesis datasets on nutrient pools and fluxes.