GRID-Arendal

Note: this report is older, written about 2009, maybe. However the trends it reports are still happening today

A new rapid response assessment report released by UNEP warns that up to 25% of the world's food production may become lost due to environmental breakdown (i.e. climate change, water scarcity, invasive pests and land degradation) by 2050 unless action is taken. Prepared by the Rapid Response Assessment Team at GRID-Arendal and UNEP-WCMC, the report provides the first summary by the UN of how climate change, water stress, invasive pests and land degradation may impact world food security, food prices and life on the planet and how we may be able to feed the world in a more sustainable manner.

The 2008 spike in food prices and a 50-200% increase in selected commodity prices triggered riots from Egypt to Haiti and Cameroon to Bangladesh, drove 110 million people into poverty and added 44 million more to the undernourished. There were dramatic impacts on the lives and livelihoods, including increased infant and child mortality of those already undernourished or living in poverty and spending 70-80% of their daily income on food.

Key causes were the combined effects of speculation in food stocks, extreme weather events, low cereal stocks, and growth in biofuels competing for cropland and high oil prices. World food prices are expected to be 30%-50% higher in coming decades and have greater volatility.

The demand for food will increase by 50% by 2050 as a result of population growth, increased incomes and growing consumption of meat.

Unless more sustainable and intelligent management of production and consumption are undertaken food prices could indeed become more volatile and expensive in a world of six billion [now 7.3 billion] rising to over 9 billion [even more with current projections] by 2050 as a result of escalating environmental degradation.

The fertilizer and pesticide-led production methods of the 20th Century are unlikely to help: they will increasingly undermine the critical natural inputs and nature-based services for agriculture such as healthy and productive soils; the water and nutrient recycling of forests to pollinators such as bees and bats.

In response to the food, fuel and financial crises of 2008 UNEP launched its Global Green New Deal and Green Economy initiatives: food is very much part of the imperative for transformational economic, social and environmental change.

Food production rose substantially in the past century, due to increasing yields due to irrigation and fertilizer use as well as agricultural expansion into new lands, with little consideration of food energy efficiency. In the past decade, however, yields have nearly stabilized for cereals and declined for fisheries. Aquaculture production to just maintain the current dietary proportion of fish by 2050 will require a 56% increase as well as new alternatives to wild fisheries for the supply of aquaculture feed.

It is uncertain whether yield increases can be achieved to keep pace with the growing food demand. Furthermore, projections have not taken into account the losses in yield and land area as a result of environmental degradation.

Land degradation, urban expansion and conversion of crops and cropland for non-food production, such as biofuels, may reduce the required cropland by 8%-20% by 2050, if not compensated for in other ways. In addition, climate change will increasingly take effect by 2050 and may cause large portions of the Himalayan glaciers to melt, disturb monsoon patterns, and result in increased foods and seasonal drought on irrigated croplands in Asia, which accounts for 25% of the world cereal production. The combined effects of climate change, land degradation, cropland losses, water scarcity and species infestations may cause projected yields to be 5%-25% short of demand by 2050. Increased oil prices may raise the cost of fertilizer and lower yields further. If losses in cropland area and yields are only partially compensated for, food production could potentially become up to 25% short of demand by 2050. This would require new ways to increase food supply.

Conventional compensation by simple expansion of croplands into low-productive rain-fed lands would result in accelerated loss of forests, steppe or other natural ecosystems, with subsequent costs to biodiversity and further loss of ecosystem services and accelerated climate change. Over 80% of all endangered birds and mammals are threatened by unsustainable land use and agricultural expansion. Agricultural intensification in Europe is a major cause of a near 50% decline in farmland birds in this region in the past three decades.

Large numbers of the world's small- scale farmers, particularly in central Asia and Africa, are constrained by access to markets and the high price of inputs such as fertilizers and seed. With lack of infrastructure, investments, reliable institutions (e.g., for water provision) and low availability of micro-finance, it will become difficult to increase crop production in those regions where it is needed the most.

Developing alternatives to the use of cereal in animal feed, such as by recycling waste and using fish discards, could sustain the energy demand for the entire projected population growth of over 3 billion people and a 50% increase in aquaculture.

Reducing climate change would slow down its impacts, particularly on the water resources of the Himalayas, beyond 2050.

A major shift to more eco-based production and reversing land degradation would help limit the spread of invasive species, conserve biodiversity and ecosystem services and protect the food production platform of the planet.

OPTIONS WITH SHORT-TERM EFFECTS

To decrease the risk of highly volatile prices, price regulation on commodities and larger cereal stocks should be created to buffer the tight markets of food commodities and the subsequent risks of speculation in markets. This would include a global fund to support micro-finance to boost small-scale farmer productivity.

Subsidies and blending ratios of first generation biofuels should be removed, which would promote a shift to higher generation biofuels based on waste (if this does not compete with animal feed), thereby avoiding the capture of cropland by biofuels. This includes removal of subsidies on agricultural commodities and inputs that are exacerbating the developing food crisis, and investing in shifting to sustainable food systems and food energy efficiency.

OPTIONS WITH MID-TERM EFFECTS

Develop alternatives to animal and fish feed by increasing food energy efficiency using fish discards, capture and recycling of post- harvest losses and waste and development of new technology, thereby increasing food energy efficiency by 30-50% at current production levels..

Support farmers in developing diversified and resilient eco-agriculture systems that provide critical ecosystem services (water supply and regulation, habitat for wild plants and animals, genetic diversity, pollination, pest control, climate regulation), as well as adequate food to meet local and consumer needs. This includes managing extreme rainfall and using inter-cropping to minimize dependency on external inputs like artificial fertilizers, pesticides and blue irrigation water.

Increased trade and improved market access as well as price regulation and government subsidies for small farmers.

OPTIONS WITH LONG-TERM EFFECTS

Limit global warming, including the promotion of climate- friendly agricultural production systems and land-use policies at a scale to help mitigate climate change.

Raise awareness of the pressures of increasing population growth and consumption patterns on sustainable ecosystem functioning.

[Editor's note: Meet the worldwide unmet need of 225 million for contraception, which would prevent 87 million pregnancies a year, contrasted with the current population growth of about 80 million per year. Reduce the consumption of meat worldwide. ]

WORLD FOOD DEMAND AND NEED

Each day 200,000 more people are added to the world food demand. Combine this with the effects rising incomes and dietary changes towards higher meat intake. Meat production is particularly demanding in terms of energy, cereal and water. Today, nearly half of the world's cereals are being used for animal feed.

Africa will experience the most rapid growth, over 70% faster than in Asia (annual growth of 2.4% versus 1.4% in Asia, compared to the global average of 1.3% and only 0.3% in many industrialized countries) (2007).

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.

An additional 3 billion could be feed by using the world's food crop more efficiently, such as eating less meat and stopping the growing biofuels on cropland. At the same time, these alternatives would support a growing green economy and greatly reduce pressures on biodiversity and water resources.

The three primary factors that affected recent increases in world crop production are: increased cropland and rangeland area (15% contribution); increased yield per unit area (78% contribution); and greater cropping intensity (7% percent contribution).

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. Of the 110-130 million tons of seafood captured annually, 70 million tons are directly consumed by humans, 30 million tons are discarded and 30 million tons 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 water. 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.

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. Areas of the coasts that are periodically starved of oxygen, so-called 'dead zones', often coincide with both high agricultural run-off and the primary fishing grounds for commercial and artisanal fisheries.

FOOD FROM MEAT

Meat production increased from 27 kg meat/capita to 36 kg meat/capita in the last two decades of the last century, and now accounts for around 8% of the world calorie intake. In addition to 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.

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. About 70% of all grazing land in dry areas is considered degraded, mostly because of overgrazing, compaction and erosion attributable to livestock. 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.

It takes, on average, 3 kg of grain to produce 1 kg of meat. About 16,000 litres of virtual water are needed to produce 1 kg of meat. Hence, an increased demand for meat results in an accelerated demand for water, crop and rangeland area. If animals are part of an integrated farm production system, the overall energy efficiency can be actually increased through better utilization of organic waste. This is not the case for mass production of pigs and poultry in specialized stables, which may take up an increasingly larger proportion of the production of feed crops.

Reducing meat consumption in the industrialized world and restraining it worldwide to 2000 level of 37,4 kg/capita in 2050 would free enough cereal to cover the annual calorie need for an additional 1.2 billion people. [ In another section, it says: "From a calorie perspective, the non-food use of cereals is thus enough to cover the calorie need for about 4.35 billion people.Taking the energy value of the meat produced into consideration, the loss of calories by feeding the cereals to animals instead of using the cereals directly as human food represents the annual calorie need for more than 3.5 billion people."]

ALTERNATIVE FEED SOURCES

Cellulose is the most abundant biological material in the world, but the energy it contains is not readily available for animal production. Due to the interest in using this material for bioethanol production, there are currently large research programs underway to chemically and enzymatically degrade this cellulose into glucose. If this becomes possible and in a cost-effective manner, wood glucose can, to a large extent, replace cereals as a feed source for both ruminants and monogastric animals.

Other sources for feed that are not fully exploited include seaweed, algae and other under-utilized marine organisms such as krill. However, their potential is uncertain, since technological challenges still remain.

FOOD - OR FEED - FROM WASTE

Discarded fish from marine fisheries is the single largest proportion lost of any food source produced or harvested from the wild. The proportion is particularly high for shrimp bottom trawl fisheries. Mortality has been estimated to be as high as 70-80%. If sustainable, the amount of fish currently discarded at sea could alone sustain more than a 50% increase in aquaculture production. However, many of these species could also be used directly for human consumption.

The potential to use unexploited food waste as alternative sources of feed is also considerable for agricultural products.

Food losses in the field (between planting and harvesting) could be as high as 20-40% of the potential harvest in developing countries due to pests and pathogens. In the United States, the losses of fresh fruits and vegetables have been estimated to range from 2% to 23%, depending on the commodity, with an overall average of about 12% losses between production and consumption sites Losses could amount to 25-50% of the total economic value because of reduced quality. Others estimate that up to 50% of the vegetables and fruits grown end as waste. Finally, substantial losses and wastage occur during retail and consumption due to product deterioration as well as to discarding of excess perishable products and unconsumed food. Food waste represents a major potential, especially for use as animal feed, which, in turn, could release the use of cereals in animal feed for human consumption.

In 2007, US$148 billion was invested in the renewable energy market, up 60% from the previous year. Recovering energy from agricultural wastes is becoming increasingly feasible at the industrial production level.

In the United States 30% of all food, worth US$48.3 billion (€32.5 billion), is thrown away each year. It is estimated that about half of the water used to produce this food also goes to waste, since agriculture is the largest human use of water. Losses at the farm level are probably about 15-35%, depending on the industry. The retail sector has comparatively high rates of loss of about 26%, while supermarkets, surprisingly, only lose about 1%. Overall, losses amount to around US$90 billion-US$100 billion a year.

Africa: In many African countries, the post-harvest losses of food cereals are estimated at 25% of the total crop harvested. For some crops such as fruits, vegetables and root crops, being less hardy than cereals, post-harvest losses can reach 50%.

Europe: United Kingdom households waste an estimated 6.7 million tonnes of food every year, around one third of the 21.7 million tonnes purchased. This means that approximately 32% of all food purchased per year is not eaten. Most of this (5.9 million tonnes or 88%) is currently collected by local authorities. Most of the food waste (4.1 million tonnes or 61%) is avoidable and could have been eaten had it been better managed.

Environmentally, food waste leads to: wasteful use of chemicals such as fertilizers and pesticides; more fuel used for transportation; and more rotting food, creating more methane - one of the most harmful greenhouse gases that contributes to climate change. Methane is 23 times more potent than CO2 as a greenhouse gas. The vast amount of food going to landfills makes a significant contribution to global warming. WRAP (Waste and Resource Action Program), a UK based group, estimates that if food were not discarded in this way in the UK, the level of greenhouse gas abatement would be equivalent to removing 1 in 5 cars from the road. [See http://www.wrap.org.uk/content/reducing-food-waste-could-save-global-economy-300-billion-year].

LOSS OF CROPLAND AREA

Land degradation and conversion of cropland for non-food production including biofuels, cotton and others are major threats that could reduce the available cropland by 8-20% by 2050. Species infestations of pathogens, weeds and insects, combined with water scarcity from overuse and the melting of the Himalayas glaciers, soil erosion and depletion as well as climate change may reduce current yields by at least an additional 5-25% by 2050, in the absence of policy intervention.

There has been a growing trend all over the world in converting cropland to other uses due to increasing urbanization, industrialization, energy demand and population growth. China, for example, lost more than 14.5 million ha of arable land between 1979 and 1995.

An additional 120 million ha - an area twice the size of France or one-third that of India - will be needed to support the traditional growth in food production by 2030, mainly in developing countries, without considering the compensation required for certain losses. The demand for irrigated land is projected to increase by 56% in Sub-Saharan Africa (from 4.5 to 7 million ha), and rainfed land by 40% (from 150 to 210 million ha) in order to meet the demand, without considering ecosystem services losses and setbacks in yields and available cropland. Increases in available cropland may be possible in Latin America through the conversion of rainforests, which in turn will accelerate climate change and biodiversity losses, causing feedback loops that may hinder the projected increases in crop yields. In Asia, nearly 95% of the potential cropland has already been utilized.

Some studies estimate that globally, 20,000-50,000 km2 of land are lost annually through land degradation, chiefly soil erosion, with losses 2-6 times higher in Africa, Latin America and Asia than in North America and Europe. The major degrading areas are in Africa south of the Equator, Southeast Asia, Southern China, North-Central Australia and the pampas of South America.

Environmental degradation and loss of ecosystem services will directly affect pests (weeds, insects and pathogens), soil erosion and nutrient depletion, growing conditions through climate and weather, as well as available water for irrigation through impacts on rainfall and ground and surface water. These are factors that individually could account for over 50% in loss of the yield in a given "bad" year. A changing climate will affect evapo-transpiration, rainfall, river flow, resilience to grazing, insects, pathogens and risk of invasions, to mention a few. In the following section we attempt to provide for each variable, rough estimates of how much environmental degradation and loss of some ecosystem services could contribute to reducing yields by 2050.

Unsustainable practices in irrigation and production may lead to increased salinization of soil, nutrient depletion and erosion. An estimated 950 million ha of salt-affected lands occur in arid and semi-arid regions, nearly 33% of the potentially arable land area of the world. Globally, some 20% of irrigated land (450,000 km2) is salt-affected, with 2,500-5,000 km2 of lost production every year as a result of salinity.

Sub-Saharan Africa is particularly impacted by land degradation. In Kenya, over the period 1981-2003, despite improvements in woodland and grassland, productivity declined across 40% of cropland - a critical situation in the context of a doubling of the human population over the same period. In South Africa, production decreased overall; 29% of the country suffered land degradation, including 41% of all cropland; about 17 million people, or 38% of the South African population, depend on these degrading areas.

Erosion is very significant in land degradation. On a global scale, the annual loss of 75 billion tonnes of soil costs the world about US$400 billion/year, or approximately US$70/person/year. It is estimated that the total annual cost of erosion from agriculture in the US is about $44 billion/year or about $247/ha of cropland and pasture. In Sub-Saharan Africa it is much larger; in some countries productivity has declined in over 40% of the cropland area in two decades while population has doubled. Overgrazing of vegetation by livestock and subsequent land degradation is a widespread problem in these regions.

The productivity of some lands has declined by 50% due to soil erosion and desertification. Yield reduction in Africa due to past soil erosion may range from 2-40%. Africa is perhaps the continent most severely impacted by land degradation.

Biofuels, including biodiesel from palm oil and ethanol from sugarcane, corn and soybean, accounted for about 1% of the total road transport in 2005, and may reach 25% by 2050. For many countries, such as Indonesia and Malaysia, biofuels are also seen as an opportunity to improve rural livelihoods and boost the economy through exports. The US is the largest producer and consumer of bioethanol, followed by Brazil. Brazil has now used 4.5% of the cropland area for biofuels, mainly sugar cane.

While biofuels are a potential low-carbon energy source, the conversion of rainforests, peatlands, savannas, or grasslands to produce biofuels in the US, Brazil and Southeast Asia may create a "biofuel carbon debt" by releasing 17 to 420 times more CO2 than the annual greenhouse gas reductions that these biofuels would provide by displacing fossil fuels. Corn-based ethanol, instead of producing a 20% savings, will nearly double greenhouse emissions over 30 years . Biofuels from switchgrass, if grown on US corn lands, will increase emissions by 50%. It is evident that the main potential of biofuels lies in using waste biomass or biomass grown on degraded and abandoned agricultural lands planted with perennials.

Production of crops for biofuels also competes with food production. The corn equivalent of the energy used on a few minutes drive could feed a person for a day, while a full tank of ethanol in a large 4-wheel drive suburban utility vehicle could almost feed one person for a year. A 2007 OECD-FAO report expected food prices to rise by between 20% and 50% by 2016 partly as a result of biofuels..

Projected losses in food production due to climate change by 2080: regional impacts will be strongest across Africa and Western Asia where yields of the dominant regional crops may fall by 15-35% once temperatures rise by 3 or 4º C. Sub-Saharan Africa is expected to be worst affected, meaning the poorest and most food insecure region is also expected to suffer the largest contraction of agricultural production and income.

Lobell et al.in 2008 identified 3 general classes of crop responses to climate change projections: 1) Consistently negative, for example, Southern African maize; 2) Large uncertainties ranging from substantially positive to substantially negative, for example, South Asian groundnut; and 3) Relatively unchanged, for example, West African wheat.

Cline in 2007 concluded that by 2080, assuming a 4.4° C increase in temperature and a 2.9% increase in precipitation, global agricultural output potential is likely to decrease by about 6%, or 16% without carbon fertilization.

Agriculture accounts for nearly 70% of the water consumption, with some estimates as high as 85%. Water scarcity will affect over 1.8 billion people by 2025. Water demand is likely to double by 2050 .

Water is probably one of the most limiting factors in increasing food production. Yields on irrigated croplands are, on average, 2-3 times higher than those on rainfed lands. Irrigated land currently produces 40% of the world's food on 17% of its land, most of it downstream and dependent upon glacial and snowmelt from the Hindu Kush Himalayas. It is evident that in regions where snow and glacial mass are the primary sources of water for irrigation, such as in Central Asia, parts of the Himalayas Hindu Kush, China, India, Pakistan and parts of the Andes, melting will eventually lead to dramatic declines in the water available for irrigation, and hence, food production.

Climate change could seriously endanger the current food production potential, such as in the Greater Himalayas Hindu Kush region and in Central Asia . Currently, nearly 35% of the crop production in Afghanistan, Bangladesh, Bhutan, China, India, Myanmar, Nepal and Pakistan is based on irrigation, sustaining over 2.5 billion people. Here, water demand is projected to increase by at least 70-90% by 2050. This also includes supply to regions of Central Asia, China and Pakistan, which are under direct water stress today.

Recent studies show that cost of water has increased by about 400-500% since 1990 in the Indo-Gangetic Basin of India.

Floods and particularly drought can offset production gains and create great fluxes in crop production, as well as in the survival of livestock. Nine major droughts in selected African countries between 1981 and 2000 resulted in an average livestock loss of 40%, with a range of 22-90%. Similar effects may be observed on crop production. Based on the extent of irrigated cropland impacted in Asia and increasing water scarcity as a result of extreme weather, an annual reduction in the future from climate-induced water scarcity and decreasing water tables may account for an estimated reduction of the world food production by 1.5% by 2030 and at least 5% by 2050.

Actual observations from Nepal indicate that current warming at high altitudes is occurring much faster than the global average, up to 0.03º C per year , and even faster at higher altitudes, up to 0.06º C per year. Scenarios suggest that the effects on the rivers are highly variable, ranging from a major increase in annual flow until around 2050 followed by a relatively rapid decline in flow for the Indus , to a gradual decline in flow in rivers such as the Brahmaputra. If temperatures rise quickly, such as >0.06º C per year, the annual flow of the rivers will invariably decline over time, particularly for those dependent on the mountains, but less so for those more dependent on the monsoons .

The combined effects of melting of glaciers, seasonal floods and overuse of ground and surface water for industry, settlements and irrigation, combined with poor water-use efficiency are difficult to estimate. However, given that 40% of the world's crop yields are based on irrigation, and almost half of this from the basins of rivers originating in the Himalayas alone, the effect of water scarcity can be substantial.

Invasive alien species (IAS) are now thought to be the second gravest threat to global biodiversity and ecosystems, after habitat destruction and degradation. The steady rise in the number of invasive alien species is predicted to continue under many future global biodiversity scenarios, although environmental change could also cause non-alien species to become invasive. Environmental change (e.g., rising atmospheric CO2, increased nitrogen deposition, habitat fragmentation and climate change) could promote further invasions. As invasive or alien species comprise over 70% of all weeds in agriculture (estimated in the US), increases in invasive species pose a major threat to food production.

Up to 70% of agricultural pests are introduced, with major impacts on global food production.

Across Africa, IAS of the genus Striga affects more than 100 million people and as much as 40% of arable land in the savannahs. These invasive species stunt maize plant growth by attacking the roots and sucking nutrients and water. Invasive alien species such as pests and diseases have been estimated to cause an annual loss of US$12.8 billion in yield of eight of Africa's principal crops.

Importantly, increased climate extremes may promote the spread of invasive species, plant diseases and pest outbreaks.

Current and future global food crises may also facilitate the spread of invasive species. Also the spread of invasive species frequently occurs in the provision of humanitarian emergency food aid. Lower sanitary and phytosanitary standards apply to food aid, particularly emergency food aid, so it may not be surprising that the introduction and spread of potentially invasive species would follow the distribution of emergency relief.

To cope with pest and disease problems, modern agriculture depends to a great extent on the use of pesticides and the continuing production of new crop varieties with specific resistance genes, although the value of integrated pest management techniques and biological control are increasingly recognized.

Small-scale farmers in developing countries continue to depend on local genetic diversity to maintain sustainable production and meet their livelihood needs. Loss of genetic choices, reflected as the loss of traditional crop varieties, therefore diminishes farmers' capacities to cope with changes in pest and disease infection, and leads to yield instability and loss. Intra-specific diversity can be used to reduce crop damage from pest and diseases today and for maintaining levels of diversity against future crop loss, that is, crop populations that have less probability that migrations of new pathogens or mutations of existing pathogens will damage the crop in the future.

In China, interplanting 2 varieties of rice has been found to have significant effects on disease incidence and productivity.

Climate change and increased CO2 assimilation in the oceans will result in increasing ocean acidification, die-back of up to 80% of the world's coral reefs and disruption of thermohaline circulation and other processes. It will particularly impact dense-shelf water cascading, a "flushing" mechanism that helps to clean polluted coastal waters and carry nutrients to deeper areas. Coastal development is increasing rapidly and is projected to impact 91% of all inhabited coasts by 2050 and contribute to more than 80% of all marine pollution. Increased development, coastal pollution and climate change impacts on currents will accelerate the spreading of marine dead zones, many in or around primary fishing grounds.

AQUACULTURE

Aquaculture production has increased more than seven-fold in weight from 1980 to 2000. In 2006, the world consumed 110.4 million tonnes of fish, of which about half originated from aquaculture. To meet the growing fish demand, aquaculture will have to produce an additional 28.8 million tonnes each year, to maintain per capita fish consumption at current levels. Aquaculture growth rate is declining, however: from 11.8% 1985-1995 to 6% 2004-2006.

THE FEED BOTTLENECK

Almost 40% of all aquaculture production is now directly dependent on commercial feed. Most farmed fish that are consumed in the developing world, such as carps and tilapia, are herbivores or omnivores. But other species like salmon or shrimp - often raised in developing countries - are fed other fish in the form of fishmeal or oil. In 2006, aquaculture consumed 56% of world fishmeal production and 87% of total fish oil production. Over 50% of the sector's use of fish oil occurs on salmon farms. Fishmeal and fish oil production has remained stagnant over the last decade and significant increases in their production are not anticipated, according to FAO. At the same time, the volume of fishmeal and fish oil used in formulated aquaculture feeds tripled between 1996 and 2006. This was made possible by a significant reduction of the poultry sector's reliance on fishmeal for poultry feeds.

As for meat production, feed is a major bottleneck. It is extremely difficult to project the future role of fisheries and aquaculture, but it is evident that the growth in aquaculture may be limited by access to feed, which, in turn is partly dependent on capture fisheries. There is no indication that today's marine fisheries could sustain the 23% increase in landings needed to sustain the 56% growth in aquaculture production required to maintain per capita fish consumption at current levels. Given the grave nature of the trends and scenarios on overfishing and ocean degradation, a future collapse of ocean fisheries would immediately affect aquaculture production and the prices of aquaculture products. Even assuming that marine fisheries landings can be maintained at current levels, the proportion of fish in the diet (in terms of calorie intake) may go down from the current 2% of world human calorie intake to 1.5% by 2030 and to only 1% by 2050. This loss will have to be compensated for by either meat or crops.

This is a very long article, but well-worth reading. Please go to the source article to read the entire report, if you are interested.