At AgroParisTech, 22 place de l'agronomie, 91120 Palaiseau, at 2:00 pm in room C2.2.43, Valentin Guye will present his thesis: "Forest, Food and Fuel: Empirical Identification of Global Sustainability Trade-offs", co-supervised by Raja Chakir, Sabine Fuss and Nicolas Koch, within the framework of a co-supervision between the University of Paris-Saclay (Paris-Saclay University) and the Universität zu Berlin.

Absract:

Sustainable development requires to improve global human systems in several dimensions, from poverty reduction and food security to energy availability and environmental conservation. Actions that help improve some dimensions of sustainability may deteriorate others, but such conflicts are not all equivalents. Therefore, aiming at sustainable development implies to make the best trade-offs. Yet, remote side-effects are hardly acknowledged, and the latent mechanisms that convey them through controllable levers are insufficiently understood.

In this doctoral dissertation, I propose three studies that contribute to the empirical understanding of global sustainability trade-offs. I focus in particular on agricultural commodities which provide a platform for trade-offs in many dimensions of sustainability. In every study, I infer causal relationships from observational data to shed lights on specific parts of these trade-offs. 

In the foremost study, I question the potential of oil palm prices as a lever to control the trade-offs between food and bio-energy availability, rural development, and environmental conservation. The study focuses on Indonesia, where these trade-offs are most acute and are globally significant. I build the first spatially explicit data set of input and output prices at the gates of half of the known palm oil mills across Indonesia. The part of this local variation that comes from downstream shocks - and is thus exogenous to local deforestation - provides a quasi-experimental setting to identify the price elasticity of deforestation. The results of this study indicate that price instruments can disincentivize deforestation, in particular for illegal and smallholder plantations that are most difficult to regulate. However, the results also highlight the conflict between environmental conservation and rural development, that needs to be addressed fairly. with environmental justice considerations.

The two other studies in this dissertation focus on the maize-ethanol mandates under the Renewable Fuel Standards (RFS) program of the United States. This policy has lifted the availability and reliability of renewable fuel for transportation, while yielding one of the largest cumulative shock on global crop markets in the last decades. The potential disruption on global ecosystems and food security are so large that the efforts to quantify them has sparked an entire literature. The second and third studies featured in this dissertation provide rare observational insights to this literature. They both leverage that the annual mandates were pre-determined in 2007, and up to 2022, as a quasi-experimental source of variation.

In the second study, I exploit this variation to detect signals of pan-tropical ecosystem disruption due to indirect land use change (ILUC) triggered by the RFS mandates. The diversity of commodities associated with these signals allows, by abductive inference, to test the ILUC theory empirically. The results corroborate the land use displacement mechanism. They also indicate the general prevalence of the mechanisms that propagate the incentives to expand cropland – including in the case of soy and temporary pasture, the major drivers of deforestation. These results warn about the reality of ILUC and contribute to better predict it to improve the sustainability trade-offs it is involved in.

In the third study, I analyze the impact of the American ethanol mandates on global food security. I observe how undernourishment prevalence evolves with the pre-determined RFS mandates, according to every country's dependency on imports for its domestic supply of calorie. I find that thanks to the mandates being announced in advance, countries could anticipate the increments in global maize demand and make preemptive adjustments that offset the otherwise worsening effect of the mandates.