In the industrial world a typical mouthful of food travels 2000 km from farmgate to consumer. The use of organic fertilizers reduces the fossil fuel consumption associated with manufacturing and distributing artificial fertilizers, thus conserving energy, further lowering CO2 emissions, and extending the life of phosphate mines. Organic compost reduces the amount of artificial fertilizer required by farmers while maintaining the organic and nutrient content of the soil. This can reduce the potential for farm-related land and water pollution and helps maintain and stabilize soils against erosion. Finally, urban nutrient recycling programs may lower both operating costs to farmers and food prices for the consumer.
Urban agriculture can contribute to enhancing biodiversity in at least two ways.
More generally, domestic gardeners tend to grow a wider variety of fruits and vegetables than large-scale commercial growers, conserving unique cultivars that might otherwise die out. Urban agriculture can spawn or help sustaining a range of new industries and employment opportunities in and near cities. Urban farming can contribute to the rebirth of civil society and development of community as neighbours cooperate in the establishment, management, and supervision of community-owned or accessible garden plots and in the evolution of related activities as described above. For example, According to the Trends Research Institute, Americans in 1997 are coming to view many of the country's mainstream socioeconomic and political structures obsolete. For all these reasons, it seems that urban agriculture makes sense on ecological, social, and economic grounds virtually everywhere on Earth.