Agricultural price volatility and economic models : Lessons from recent crisis

The recent price spike on international agricultural markets took experts by surprise, most economists worrying about the long term decline of agricultural prices, and calls into question one of the most widespread political recommendations over the last three decades: "liberalize trade and trust international markets with regard to food security". Nevertheless, according to the most classical economic theory, such behaviour of agricultural prices was to be expected. However, certain fundamentals of market price dynamics have often been neglected in world models. An alternative representation of price formation in a world model is presented and its results discussed. (Resume d'auteur)