in fertiliser production, has been increasing. But known supplies of readily accessible, high-grade stocks, especially phosphate rock, are falling. Estimates of the longevity of these stocks vary dramatically.11
Nevertheless, only one-
fifth of the phosphorus mined for food production actually contributes to the food we consume, while the remainder is either polluting the world’s water or accumulating in soils or urban landfills (Cordell et al. 201012
). Although it
is expected that the increasing prices of phosphates and other minerals will lead to increases in supplies, including recovery of phosphate from wastewater treatment facilities, these prices are likely to continue to put upward pressure on the cost of fertilisers and food prices, which affects the poor’s access to food disproportionately.
Post-harvest spoilage Today, the volume of food produced globally is more than sufficient to feed a healthy population. But significant amounts of food produced around the world are lost or wasted after harvesting. As Figure 9b shows, in developed countries this primarily occurs in the retail, home and municipal food-handling stages. For example in the USA, around 40 per cent of all food produced is wasted, resulting in losses of all embedded inputs such as energy (equivalent to wasting 350 million barrels of oil per year), water (equivalent to about 40 trillion litres of water every year) and huge volumes of fertilisers and pesticides (Hall et al. 2009). Losses in developed countries are often caused by factors such as retailers’
10. Retail, food service, and home and municipal are aggregated for developing countries.
11. Steén (1998) indicates that phosphate stocks will be depleted by 50-100 per cent by the end of 21st century, whereas Isherwood (2003) suggests that supplies could last between 600-1,000 years.
rejection of produce due to poor appearance or super- sized packages leading to post-retail spoilage. The latter can account for up to 30 per cent of the food bought by retail distributors. Post-retail food losses tend to be lower in developing countries. There, they mainly result from a lack of storage facilities, on-farm pest infestations, poor food-handling and inadequate transport infrastructure. For example, rice losses in developing countries may be as high as 16 per cent of the total harvest (Mejía 200313
).
Thus, there is ample scope for increasing food supplies and food security in developing countries through simple targeted investments in post-harvest supply chains.
Rural labour The accelerating migration of rural populations to urban and peri-urban areas in developing regions of the world (Figure 6) has resulted in significant demographic changes in rural populations. Working-age men are likely to relocate to cities in search of employment, reducing the pool of men available for agricultural work. This rural out-migration of men has also resulted in a dominant role for women as smallholders in these regions; more than 70 per cent of smallholders in sub-Saharan Africa are women (World Bank, FAO and IFAD 2009). These demographic changes, while offering economic opportunities, have placed additional responsibilities on women, who invariably also have to care for their children and the elderly.
Increased vulnerability of agriculture due to climate change Modelling by the IPCC suggests that crop productivity could increase slightly at mid- to high-latitudes for mean temperature increases of up to 1-3°C (depending on the crop) (Easterling et al. 2007). However, at lower latitudes, especially in the seasonally dry and tropical regions, crop