EGU21-12561
https://doi.org/10.5194/egusphere-egu21-12561
EGU General Assembly 2021
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Evaluation of soil carbon dynamics after land use change in CMIP6 land models using chronosequences

Victor Brovkin1,2, Lena Boysen1, David Wårlind3, Daniele Peano4, Anne Sofie Lansø5, Christine Delire6, Eleanor Burke7, Christopher Poeplau8, and Axel Don8
Victor Brovkin et al.
  • 1Max Planck Institute for Meteorology, The Land in the Earth System, Hamburg, Germany (victor.brovkin@mpimet.mpg.de)
  • 2Center for Earth System Research and Sustainability, University of Hamburg, Germany
  • 3Institute for Physical Geography and Ecosystem Sciences, Lund University, Lund, Sweden
  • 4Fondazione Centro euro-Mediterraneo sui Cambiamenti Climatici, Bologna, Italy
  • 5Laboratoire des Sciences du Climat et de l’Environnement (LSCE/IPSL) CEA-CNRS-UVSQ, Université Paris-Saclay, Gif-sur-Yvette, France
  • 6CNRS, Université de Toulouse, Météo-France, Toulouse, France
  • 7Met Office Hadley Centre, Exeter, UK, EX1 3PB
  • 8Thünen Institute of Climate-Smart Agriculture, Braunschweig, Germany

Land surface models are used to provide global estimates of soil organic carbon (SOC) changes after past and future land use change (LUC). To evaluate how well the models capture decadal scale changes in SOC after LUC, we provide the first consistent comparison of simulated time series of LUC by six land models all of which participated in the Coupled Model Intercomparison Project Phase 6 (CMIP6) with soil carbon chronosequences (SCC). For this comparison we use SOC measurements of adjacent plots at four high-quality data sites in temperate and tropical regions. We find that initial SOC stocks differ among models due to different approaches to represent SOC. Models generally meet the direction of SOC change after reforestation of cropland but the amplitude and rate of changes vary strongly among them. Further, models simulate SOC losses after deforestation for crop or grassland too slow due to the lack of crop harvest impacts in the models or an overestimation of the SOC recovery on grassland. The representation of management, especially nitrogen levels is important to capture drops in SOC after land abandonment for forest regrowth. Crop harvest and fire management are important to match SOC dynamics but more difficult to quantify as SCC hardly report on these events. Based on our findings, we identify strengths and propose potential improvements of the applied models in simulating SOC changes after LUC.

How to cite: Brovkin, V., Boysen, L., Wårlind, D., Peano, D., Lansø, A. S., Delire, C., Burke, E., Poeplau, C., and Don, A.: Evaluation of soil carbon dynamics after land use change in CMIP6 land models using chronosequences, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-12561, https://doi.org/10.5194/egusphere-egu21-12561, 2021.

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