Impact of taking into account changes in land use on the calculation of carbon substitution by wood products

The underlying principle of "carbon substitution" is to replace a product with a substitute that offers the same service but whose life cycle emits less greenhouse gas (GHG). Substitution is therefore defined as the emissions differential between the two resulting alternative trajectories. In the forestry and wood industries, mitigation strategies are largely based on this principle applied to wood products as a substitute for non-wood products. To date, the available literature presents a wide range of values for substitution by wood products, even when the products and contexts studied are similar. Our hypothesis is that these disparities are due to an incomplete consideration of carbon emissions related to the life cycle of wood products, in particular indirect emissions related to land use changes.

The objective of this thesis is to test this hypothesis by providing a methodology for calculating wood product substitution that takes into account emissions induced by land use change. This methodology is based on the coupling of a national forest sector model (French Forest Sector Model - FFSM) with a global land use model (Nexus Land Use). The results of this coupling will provide the necessary ingredients for a consequential Life Cycle Assessment (LCA) for French wood products.

The thesis will thus lift important scientific barriers: its results will strengthen carbon accounting methodologies in environmental sciences, climate sciences, forest sciences, and environmental and energy economics. From a decision support point of view, the project will improve the carbon proxy values used in national and international bodies.