Effects of model structural uncertainty on carbon cycle projections: biological nitrogen fixation as a case study

By William R. Wieder, C. Cleveland, D. Lawrence, Gordon Bonan. 2015

140 citations recorded by the source corpus.

Uncertainties in terrestrial carbon (C) cycle projections increase uncertainty of potential climate feedbacks. Efforts to improve model performance often include increased representation of biogeochemical processes, such as coupled carbon–nitrogen (N) cycles. In doing so, models are becoming more complex, generating structural uncertainties in model form that reflect incomplete knowledge of how to represent underlying processes. Here, we explore structural uncertainties associated with biological nitrogen fixation (BNF) and quantify their effects on C cycle projections. We find that alternative plausible structures to represent BNF result in nearly equivalent terrestrial C fluxes and pools through the twentieth century, but the strength of the terrestrial C sink varies by nearly a third (50 Pg C) by the end of the twenty-first century under a business-as-usual climate change scenario representative concentration pathway 8.5. These results indicate that actual uncertainty in future C cycle projections may be larger than previously estimated, and this uncertainty will limit C cycle projections until model structures can be evaluated and refined.

Subfields: Global and Planetary Change, Oceanography

View Paper: https://www.semanticscholar.org/paper/5e96b0f579d6633e79e0cb11617398f27b644b4f

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Global and Planetary Change

1. Jasper A. Vrugt
2. Chonggang Xu
3. R. Fisher
4. M. Clark
5. Gordon Bonan
6. D. Lawrence
7. C. Koven
8. L. Ruby Leung

In Oceanography

1. D. Lawrence
2. Pierre Gentine
3. S. Swenson
4. William R. Wieder
5. Gordon Bonan
6. John M. Wahr
7. Isabella Velicogna
8. Jürgen Kusche

Citations in the corpus

• The Community Land Model Version 5: Description of New Features, Benchmarking, and Impact of Forcing Uncertainty (2019, methodology): “Preliminary investigation suggests that although the plant hydraulics scheme does tend to reduce variability in GPP and transpiration (see section 4.4), it does not appear to be primarily responsible for the reduced C flux variability in CLM5, with the reduced variability potentially resulting from ”
• A global scale mechanistic model of photosynthetic capacity (LUNA V1.0) (2016, background): “It has been suggested recently that nitrogen-related factors are not well rep- resented in ESMs (Houlton et al., 2015; Wieder et al., 2015).”