The world food production has increased substantially in the past century, as has calorie intake per capita. However, in spite of a decrease in the proportion of undernourished people, the absolute number has in fact increased during the current food crisis, to over 963 million. By 2050, population growth by an estimated 3 billion more people will increase food demand.
Increased fertilizer application and more water usage through irrigation have been responsible for over 70% of the crop yield increase in the past. Yields, however, have nearly stabilized for cereals, partly as a result of low and declining investments in agriculture. In addition, fisheries landings have declined in the past decade mainly as a result of overfishing and unsustainable fishing methods.
Food supply, however, is not only a function of production, but also of energy efficiency. Food energy efficiency is our ability to minimize the loss of energy in food from harvest potential through processing to actual consumption and recycling. By optimizing this chain, food supply can increase with much less damage to the environment, similar to improvements in efficiency in the traditional energy sector. However, unlike the traditional energy sector, food energy efficiency has received little attention. Only an estimated 43% of the cereal produced is available for human consumption, as a result of harvest and post-harvest distribution losses and use of cereal for animal feed. Furthermore, the 30 million tonnes of fish needed to sustain the growth in aquaculture correspond to the amount of fish discarded at sea today.
A substantial share of the increasing food demand could be met by introducing food energy efficiency, such as recycling of waste. With new technology, waste along the human food supply chain could be used as a substitute for cereal in animal feed. The available cereal from such alternatives and efficiencies could feed all of the additional 3 billion people expected by 2050. At the same time, this would support a growing green economy and greatly reduce pressures on biodiversity and water resources – a truly ‘win-win’ solution.
FOOD FROM CROPS
The three primary factors that affected recent increases in world crop production are (FAO, 2003; 2006):
- Increased cropland and rangeland area (15% contribution in 1961–1999);
- Increased yield per unit area (78% contribution); and
- Greater cropping intensity (7% percent contribution).
Trends in crop production and in these three factors are illustrated in Figures 7, 8 and 9.
|Figure 7: Production increase in yield and area (1965–2008) of several key crops. Yield increases have generally exceeded areal increases. (Source: World Bank, 2009).
||Figure 8: Global trends (1960–2005) in cereal and meat production, use of fertilizer, irrigation and pesticides. (Source: Tilman, 2002; FAO, 2003; International Fertilizer Association, 2008; FAOSTAT, 2009).
The use of fertilizers accounts for approximately 50% of the yield increase, and greater irrigation for another substantial part (FAO, 2003). Current FAO projections in food demand suggest that cereal demand will increase by almost 50% towards 2050 (FAO, 2003; 2006). This can either be obtained by increasing yields, continued expansion of cropland by conversion of natural habitats, or by optimizing food or feed energy efficiency from production to consumption.
|Figure 9: Increase in crop production has mainly been a function of increases in yield due to increased irrigation and fertilizer use. However, this may change in the future towards more reliance on cropland expansion, at the cost of biodiversity. (Source: FAO, 2006).
FOOD FROM FISHERIES AND AQUACULTURE
Aquaculture, freshwater and marine fisheries supply about 10% of world human calorie intake – but this is likely to decline or at best stabilize in the future, and might have already reached the maximum. At present, marine capture fisheries yield 110–130 million tonnes of seafood annually. Of this, 70 million tonnes are directly consumed by humans, 30 million tonnes are discarded and 30 million tonnes converted to fishmeal.
The world’s fisheries have steadily declined since the 1980s, its magnitude masked by the expansion of fishing into deeper and more offshore waters (Figure 10) (UNEP, 2008). Over half of the world’s catches are caught in less than 7% of the oceans, in areas characterized by an increasing amount of habitat damage from bottom trawling, pollution and dead zones, invasive species infestations and vulnerability to climate change (UNEP, 2008). Eutrophication from excessive inputs of phosphorous and nitrogen through sewage and agricultural run-off is a major threat to both freshwater and coastal marine fisheries (Anderson et al., 2008; UNEP, 2008). Areas of the coasts that are periodically starved of oxygen, so-called ‘dead zones’, often coincide with both high agricultural run-off (Anderson et al., 2008) and the primary fishing grounds for commercial and artisanal fisheries. Eutrophication combined with unsustainable fishing leads to the loss or depletion of these food resources, as occurs in the Gulf of Mexico, coastal China, the Pacific Northwest and many parts of the Atlantic, to mention a few.
Current projections for aquaculture suggest that previous growth is unlikely to be sustained in the future as a result of limits to the availability of wild marine fish for aquaculture feed (FAO, 2008). Small pelagic fish make up 37% of the total
marine capture fisheries landings. Of this, 90% (or 27% of total landings) are processed into fishmeal and fish oil with the remaining 10% used directly for animal feed (Alder et al., 2008).
In some regions, such as in parts of Africa and Southeast Asia, increase in fisheries and expansion of cropland area have been the primary factors in increasing food supply. Indeed, fisheries are a major source of energy and protein for impoverished coastal populations, in particular in West Africa and Southeast Asia (UNEP, 2008). Here, a decline in fisheries will have a major impact on the livelihoods and wellbeing of hundreds of millions of people (UNEP, 2008).
|Figure 10: Fishing has expanded deeper and farther offshore in recent decades (left panel). The decline in marine fisheries landings has been partly compensated for by aquaculture (right panel). (Source: FAO FISHSTAT, MA, 2005; UNEP, 2008).
FOOD FROM MEAT
Meat production increased from 27 kg meat/capita in 1974/1976 to 36 kg meat/capita in 1997/1999 (FAO, 2003), and now accounts for around 8% of the world calorie intake (FAOSTAT, 2009). In many regions, such as in the rangelands of Africa, in the Andes and the mountains of Central Asia, livestock is a primary factor in food security.
Meat production, however, also has many detrimental effects on the environment, apart from being energy inefficient when animals are fed with food-crops. The area required for production of animal feed is approximately one-third of all arable land. Dietary shifts towards more meat will require a much larger share of cropland for grazing and feed production for the meat industry (FAO, 2006; 2008).
Expansion of land for livestock grazing is a key factor in deforestation, especially in Latin America: some 70% of previously forested land in the Amazon is used as pasture, with feed crops covering a large part of the remainder (FAO, 2006b). About 70% of all grazing land in dry areas is considered degraded, mostly because of overgrazing, compaction and erosion attributable to livestock (FAO, 2006b). Further, the livestock sector has an often unrecognized role in global warming – it is estimated to be responsible for 18% of greenhouse gas emissions, a bigger share than that of transport (FAO, 2006b).