The term globalization, which is used to sum up the recent shift in international economic relations, refers to the increasing interdependence of world economies, combined with more intense exchanges of both goods and capital. Under the auspices of the GATT and then the WTO, this shift has also seen increasing State withdrawal, known as liberalization. Farming, which was long seen as an exceptional sector, has been at the heart of international talks since the Uruguay Round and the 1994 Marrakech agreement. The sector, which is involved in greenhouse gas emissions and sequestration, is also directly concerned by the international talks on global change. Liberalization is expected to result in a global increase in wellbeing, linked on the one hand to increased efficiency through specialization, and on the other hand to the fact that any shocks are spread over a broader market, thus reducing their adverse effects. This is one of the major results of economic theory, illustrated by many simulations backed up by figures, which have estimated the gains in terms of billions of dollars. However, although these results are guaranteed in a theoretical perfect market, they are in fact far from the reality of the current global market, whose very considerable fluctuations can induce huge efficiency losses.