purchase much of their food in wet markets or in the surrounding small shops that deal in specific grains and legumes. Foods processed on the street are available for immediate consumption.
It is important to note, however, that neither the modern food systems nor the traditional systems assure long term food security for all. Affordability, physical access, and volatility of both supply and price compromise the ability of poor families and individuals to achieve food security. Furthermore, both modern systems and traditional systems use environmental services in unsustainable ways (Pretty, 2006).
Many of the traditional, family-based systems fail to produce enough food or income to assure that even the producing family has access to a nutritionally adequate diet. Furthermore, surpluses produced by more commercially oriented small-holder farms are not sufficient, in many countries, to assure that all consumers have access to locally sourced, nutritionally adequate supplies at all times at prices they can afford. These countries must, to some extent, rely on imports of food. Low-productivity traditional systems often over-use or mismanage the environmental resources on which future productivity depends: applying insufficient fertilizers to replace nutrients extracted as crops, overgrazing pasturelands held in common, and using groundwater inefficiently.
Modern food systems are more successful in producing reliable supplies of food, but even wealthy, surplus-producing countries do not assure that food is available cheaply enough for all consumers. Supplementary public assistance, such as food stamps, is necessary to cover the affordability gap. Nor are many of the highly developed, industrial food systems sustainable in environmental terms. Damage to the productive capacity of natural resources is rarely integrated into the product pricing structures. Lowering of the groundwater level, pesticide pollution, the effects of poorly managed contaminants, and other environmental impacts generated by the system are rarely included in the price the consumer pays for the food. Rather, these costs are borne by the population at large or result in uncompensated degradation of the natural environment. In effect, failure to include environmental costs into costs of production results in transfers from future to current generations; that is, future generations will face higher costs of production because of the failure to incorporate environmental costs now. On the other hand, incorporating the costs of environmental degradation would increase food prices, and if inappropriately managed, could cause increasing hunger and malnutrition in current generations of low-income people.
The rapid rise in global food prices in 2007-2008 and more recent price volatility have reminded the world of the continued importance of having nutritionally adequate food supplies that are affordable, available in sufficient quantities, and predictably available. It is generally agreed that in the next decades, growing populations and economic expansion will inevitably create supply disruptions and put upward pressure on prices unless agricultural production and productivity are increased; trade mechanisms become much more efficient; and policies are changed to reduce the affect on food crops, for example, those promoting the processing of food crops into biofuels.
It is also generally agreed that the process of climate change will have a negative impact on the production potential of much of the tropics and sub-tropics, the area of the world in which population growth is currently most rapid. While greater productivity in temperate zones could partially compensate for this decline, it is not clear that redistribution from supplying areas to consuming areas could occur at affordable cost, nor is it clear how natural resources would be affected.