PhD candidate Elisa Bruni from the Climate and Environmental Sciences Laboratory (LSCE) in France is pleased to invite you to her doctoral thesis defence entitled “Soil organic carbon modelling: estimating carbon input changes required to reach policy objectives aimed at increasing soil organic carbon stocks”.
The defence will take place on Monday 28 March 2022 at 2:00 p.m. in Amphi 7 of AgroParisTech (Paris-Maine), located at 19 Avenue du Maine, 75015 Paris. For those who prefer to attend remotely, you can join the videoconference through the following link (Meeting ID: 930 0252 2076 / Password: 954715). The presentation will be held in English.
The thesis jury board is composed of the following experts:
- Axel DON, Senior Lecturer, Thünen Institute (Germany) – Rapporteur & Examiner
- Isabelle BASILE, Research Director, INRAE Centre PACA (France) – Rapporteur & Examiner
- Sébastien Barot, Director of Research, IRD (France) – Examiner
- Patricia Garnier, Director of Research, INRAE (France) – Examiner
- Emanuele Lugato, Project manager, Joint Research Centre (Europe) – Examiner
- Stefano Manzoni, Senior Lecturer, Stockholm University (Sweden) – Examiner
- Claire Chenu, Director of Research, INRAE (France) – Thesis director
- Bertrand Guenet, Research Fellow, INRAE (France) – Examiner
- Denis Angers, Honorary Director of Research, Université de Laval (Canada) – Invited
- Gaby Deckmyn, Senior Scientist, University of Antwerp (Belgium) – Invited
To partially compensate for CO2 emissions, the 4 per 1000 initiative proposed an annual 4‰ soil organic carbon (SOC) stock increase. Yet, the feasibility of such an ambitious target is still under debate. The most efficient way to increase the SOC stocks is to increase the C input to the soil. The objective of this thesis was to estimate the C input required to yearly increase the SOC stocks by 4‰ in European croplands.
To solve this problem, we built an inverse modelling approach and tested it on a SOC model, by estimating the C input required to reach the 4‰ objective at multiple long-term agricultural experiments in Europe. Then, we applied this approach to a multimodel ensemble, to assess the uncertainties of the estimations according to different representations of the SOC dynamics. As a first attempt to provide insights for policymakers on the feasibility of a 4‰ target in Europe, we applied a multi-model ensemble over the whole European cropland area, and we generated maps of the required C input under two scenarios of climate change. To improve the simulation of SOC stocks at the European scale, we tested a new, statistically derived, parametrization technique.
Our study demonstrates that there are substantial uncertainties around the C input required to reach a 4‰ target. However, a general pattern emerges at the European cropland scale, where the 4‰ target seems feasible under future scenarios of climate change, only assuming drastic increases of C input to the soil.