Nitrogen and phosphorus limitation on land carbon uptake
ACCESS-ESM1.5 has been used to simulate land carbon uptake when atmospheric carbon dioxide increases. Simulations are performed with and without nitrogen and phosphorus limitation. The results are presented in a July 2021 paper in Environmental Research Letters by Ziehn and co-authors:
Increasing carbon dioxide leads to increasing land carbon uptake: the ‘land carbon-concentration feedback’. Increasing temperature (from increasing carbon dioxide) leads to decreasing land carbon uptake: ‘the land carbon-climate feedback’. The analysis described in the paper finds that land carbon uptake and feedback strength is reduced by about 30% when nitrogen limitation is included. Adding phosphorus limitation, the response is even stronger with a further 50% reduction for the carbon-concentration feedback and a further 75% reduction for the carbon-climate feedback. The study is important for improving estimates of future land carbon uptake and for assessing the effectiveness of land-based carbon mitigation.
Global land carbon uptake varies depending on whether nitrogen and phosphorus limitation is included in the simulation. See Figure 1d, Ziehn et al. (2021) for details.