Impact du taux de change sur la sécurité alimentaire des pays en développement

[Paper in French] The issue of world food security is still at the core of international concerns with the rising prices of agricultural products over the period 2006-2008. In this context, most of the least developed countries are net importers of agricultural products since the beginning of the 1990s. Moreover, recent years have also been marked by the debate on exchange rates, as evidenced by the Yuan/dollar currencies dispute. In line with the literature on the relationship between the exchange rate and trade, the objective of this article is to evaluate the relationship between the exchange rate and food security over the period 1995-2010 on a sample of 24 to 72 developing countries. In addition, we propose a theoretical framework to highlight the economic links between food security, measured by the indicator of Bonilla, the value of the currencies of the countries and the terms of trade. This theoretical analysis suggests that a depreciation of the national currency leads in the short term to a deterioration of food security (measured with Bonilla Index) due to the higher bill of food imports and the decrease in export revenues. The long term relationship depends on the price elasticities of demand for food imports, the supply of exports and of the ratio of imported food prices relative to prices of other imported products. Finally, two case studies (one on the Gambia, the other on the Côte d'Ivoire) suggest that the exchange rate is not the sole determinant of food insecurity. The level of food security may also depends on other variables such as investments, the level of customs duties, the terms of trade, the money supply and political stability.