Exporters's behaviour in the face of climate volatility. With Philippe Bontems (Toulouse School of Economics), Jean-Marie Cardebat (University of Bordeaux) and Raphaël Chiappini (University of Bordeaux) (Link) 

Abstract: This paper investigates how exporters adjust trade margins to demand shocks and climate-induced production volatility. Combining French wine export data (113 PDOs, 49 destinations, 2001–2020) with high-resolution weather records, we estimate theory-consistent structural gravity models using instrumental variables that exploit exogenous variation in extreme temperatures. Production volatility significantly reduces export volumes, while demand shocks shape market allocation. A heterogeneity shows that exporters absorb production shocks by reallocating supply across markets, protecting volumes in core destinations while curtailing shipments to less profitable peripheral ones. A theoretical model of risk-averse heterogeneous firms rationalizes these findings through scale, redeployment, and selection effects driving export reallocation under climate risk. 

Keywords: Climate change, Cost shocks, Demand shocks, Gravity model, Heterogeneous firms, Risk averse firms.

Natural disasters and export dynamics: The case of flood exposure in France.

Abstract: This article examines the impact of flood exposure on the composition of international trade flows. We combine a dataset of French wine shipments over the 2001-2020 period and accounting for 113 Protected Denomination of Origin (PDO), with aggregated data of flood exposure initially recorded at the municipal level. We apply gravity models and local projections on our panel data to consider the aftermath floods occurrence on trade margins and prices. This allows us to compare potential effects resulting from both static and dynamic approaches. Our findings reveal a significant and negative relationship between the increase in flood exposure and the intensive margin, while no evidence are captured for both extensive margin and unit values. Persistent effects are found for the shortfall in export volumes while there is an additional supply shock corresponding to flood occurrence.

Keywords: Floods, Natural disasters, Supply shock, International trade, Gravity model, Local projections.

Is organic farming an adaptation to climate change? Evidence from French grape yields. With Magali Delmas (UCLA IoES and UCLA Anderson School of Management) and Louis Jordi (University of Bordeaux)

Abstract: As climate shocks become increasingly frequent and severe, organic farming conversion may represent a viable adaptation strategy for wine producers. Using data from the French Farm Accountancy Data Network (FADN) for an unbalanced panel of approximately 950 French vineyards over the 2008-2023 period, this paper investigates the extent to which the sensitivity of grape yields to meteorological conditions differs across conventional and organic production systems. The analysis relies on a two-way fixed effects model exploiting annual local variation in weather conditions within each farm. Four climate indicators are considered: frost risk, growing degree days (GDD), killing degree days (KDD), and downy mildew pressure. The results reveal differentiated responses to climate shocks between organic and conventional farms, as well as a critical trade-off for the wine industry under future climate scenarios (RCP2.6, 4.5, and 8.5), projected using the regional climate model ALADIN over the medium (2036–2065) and long term (2070–2099). Overall, organic farming emerges as a particularly relevant adaptation strategy in contexts of intense warming, with a mitigation potential that grows with the severity of the climate scenario.  

Keywords: Climate change, Organic farming, Adaptation strategies, Climatic projections.