Urban agriculture provides an estimated 15 percent of all food consumed in urban areas and is likely to double that share in the next couple of decades. Some cities even export surpluses abroad. Urban agriculture is also integral to city life, a vibrant part of urban economic and ecological systems. Urban farmers use urban land, public services, inputs, and even urban wastes in production. They then sell to local markets and often reinvest profits into goods produced or sold at city outlets.
Urban agriculture can be an important supplement to household income.
In Cairo, the rearing of small livestock, practiced by over a quarter of households, provides more than 60 percent of household income. In Dar es Salaam urban agriculture is the second largest employer. Still, the great majority of urban farmers are poor and grow food mainly for their own subsistence, with little support or protection, on small plots that they do not own. These households can secure food from urban agriculture that they could not afford otherwise. Studies in Harare, Kampala, and Nairobi found that urban agriculture can improve nutritional status of household members, as measured by caloric and protein intake, meal quality, or children's growth rates.