Évaluation de la vulnérabilité des fermes productrices de maïs-grain du Québec aux variabilités et changements climatiques : les cas de Montérégie-Ouest et du Lac-Saint-Jean-Est

The undertaking of vulnerability studies in relation to climatic change and vulnerability at the international and national levels renders them less relevant to a decision-making process at smaller spatial scales where specific response strategies are implemented. Vulnerability studies to climatic change and variability at relatively small geographic scales within the agriculture sector are rare in general, and even nonexistent in Canada, including Quebec. In order to fill in this gap and to contribute to a better decision-making process at the farm level, this study aimed at presenting a description and analysis of the evolution of grain corn growers’ vulnerability to climatic change and variability and other stressors within the Montérégie-Ouest and Lac-St-Jean-Est regions. A general methodology consisting of an assessment of farmers’ overall vulnerability by combining vulnerability profiles to climate and socio-economic conditions has been considered. For the reference period (1985-2005), vulnerability profiles were constructed by analyzing the variation coefficients  of grain corn yields and crop area data. By means of ethnographic methods associated with a multicriteria analysis technique, the Analytic Hierarchy Process (AHP), adaptive capacity indices  of the agriculture sector have been elaborated upon for the reference period. These indices have then been used as a starting point in the construction of scenario indices of future adaptive capacity of farmers for the future period 2010-2039. For this future period (2010-2039), vulnerability profiles for both regions have been created using a simplified version of the Intergovernmental Panel on Climate Change (IPCC) conceptual framework on the components of vulnerability. For the « sensitivity » component of grain corn growers to climate conditions within the selected agricultural regions, a set of grain corn yields has been simulated using five climate scenarios coupled with CERES-Maize, one of the crop models embedded in the Decision Support System for Agrotechnology Transfer (DSSAT 4.0.2.0 version) software. In regards to the evaluation of the « adaptive capacity » for the future period (2010-2039), the elaboration of indices for this component has been undertaken by considering the potential influence of the main economic and environmental drivers used in the development of the storylines for two greenhouse gas (GHG) emission scenarios families, namely the A2 and A1B families.   The application of the methodological approach mentioned above produced the following key results. For the reference period, the Lac-St-Jean-Est region appeared to be more vulnerable to climate conditions than Montérégie-Ouest region. The coefficient of variation for grain corn yields within the Lac-St-Jean-Est region was evaluated to be 0,35, while the value for the Montérégie-Ouest region was only 0,23. However, with respect to the socio-economic conditions, the Montérégie-Ouest region showed greater vulnerability than the Lac-St-Jean-Est region. The values of the coefficient of variation for the areas under grain corn during the reference period (1985-2005) within Montérégie-Ouest and Lac-St-Jean-Est were 0,66 and 0,48 respectively.  For the future period (2010-2039), the Lac-St-Jean-Est region, once again, would seem to be more vulnerable to climate conditions than the Montérégie-Ouest region. The average values of the coefficient of variation for the simulated grain corn yields fluctuate between 0,21 and 0,25 for the Montérégie-Ouest region and between 0,31 and 0,50 for Lac-St-St-Jean-Est region. However, from a socio-economic perspective, the relative vulnerability status of both regions would seem to vary according to the scenario of adaptive capacity considered. With the economic and environmental drivers considered in the storylines of the A2 GHG emissions scenario family, the adaptive capacity indices for the sector under study would be 0,13 and 0,08 for Montérégie-Ouest and Lac-St-Jean-Est, respectively. On the other hand, by considering the economic and environmental drivers considered for the A1B GHG emissions scenario family, the Lac-St-Jean-Est agricultural region would appear to have an adaptive capacity slightly higher (0,07) than that of the Montérégie-Ouest region (0,06). In general, for the future period, the Lac-St-Jean-Est region would appear to have greater overall vulnerability than the Montérégie-Ouest. This situation can be explained mainly by a greater vulnerability of Lac-St-Jean-Est region to climate conditions.  The results of this study have to be interpreted within the context of the assumptions considered, the methodology used, and the characteristics of the two regions under study. In general, using a simple methodological approach, this study revealed the « dynamic and relative » characteristics of the vulnerability concept, the importance of spatial scale and consideration of multiple stressors and the integration of an approach different to the commonly used« dumb-farmer  » approach for the evaluation of this concept of vulnerability within the agriculture sector. Finally, this study has also identified some new research pathways likely to contribute to a better evaluation of farmers’ vulnerability to climate change in the context of multiple stressors.

Keyphrases: Climate change, Vulnerability, Agriculture, Agriculture, DSSAT, DSSAT, Analytic hierarchy process, Adaptive capacity