The climate is changing and most of the change is caused by human activity. We have drained peatlands and chopped down forests to provide us with fertile agricultural soil, and we have used the animals in our care in often unspeakably cruel ways.
The process of feeding ourselves has always had damaging consequences for our land (Diamond, 2005) and the animals we have reared. We have drained peatlands and chopped down forests to provide us with fertile agricultural soil, and we have used the animals in our care in often unspeakably cruel ways (Thomas, 1991).
Until now though, we have always been able to expand our way out of the problem. There was always new land to use. The situation today is very different: there are more of us – but there are no more planets to exploit. By 2050 there will be 9 billion or more of us on this earth and each one of us will need to eat. What we eat, and how we produce it, has a profound impact upon the long-term sustainability of the planet. Worryingly however, the patterns of production and consumption that we in the developed world have adopted, and that the developing world is rapidly taking up, have potentially catastrophic consequences.
One of the major causes for concern is the rapid growth in the production and consumption of foods of animal origin. Apart from the potential welfare implications of how we actually rear these animals, the growth in livestock farming has damaging consequences for biological diversity, for water extraction and use, for soil and air pollution – and for climate change, which is the primary focus of this chapter.
We show that tackling climate changing emissions will require us to reduce the number of animals we rear and to change the way we rear them; and we will need to eat fewer foods of animal origin. This said, livestock production can also very much form a part of the solution – farm animals can help create a resilient, sustainable, biodiverse food system, if we rear them in the right way and at moderate scales.
Finally, the livestock-climate issue cannot and must not be seen as standing in opposition to development objectives, and in particular to the right of all people to food security. We need to develop strategies that explicitly link the goals of ensuring food security, with that of achieving greenhouse gas (GHG) emission reductions from the agricultural and food sectors.
Climate change and international development: Twin problems
The climate is changing and most of the change is caused by human activity. The latest report (2007) by the Intergovernmental Panel on Climate Change (IPCC) concludes that ‘Warming of the climate system is unequivocal…’ what is more, ‘Most of the observed increase in globally averaged temperatures since the mid-20th century is very likely1 due to the observed increase in anthropogenic greenhouse gas concentrations.’ (original emphasis)
In the last 100 years we have seen a global rise in temperature of 0.74°C. 11 of the last 12 years (1995–2006) have been the warmest since records began in 1850 (Schneider et al, 2007). Under ‘business-as-usual’ (BAU) scenarios, the IPCC warns that we are likely to see a temperature rise of about 3°C by 2100 relative to the end of the 20th century, within a possible range of 2°C to 4.5°C (IPCC, 2007). Other more recent studies suggest that the upper end of the estimate is more likely (Anderson and Bows, 2008). It is generally accepted that a rise of 2°C above pre-industrial levels, equivalent to a concentration of CO2 equivalent (CO2e) in the atmosphere above 450 parts per million (ppm), delivers the probability of ‘dangerous climate change’ (Schellnhuber et al, 2006).
We could then experience major irreversible system disruption, with hypothetical examples including a sudden change in the Asian monsoon or disintegration of the west Antarctic ice sheet (Schneider et al, 2007). Note that even at 450ppm there is only a 50 per cent chance of keeping the temperature rise to 2°C or lower (Hadley Centre, 2005). What is more, even if the world stopped emitting any more GHGs as of now, we would still be ‘committed’, due to time lags in the Earth’s climate mechanisms, to a rise of 1°C by the end of the century (or 0.1°C per decade). In short, we have very little room left for manoeuvre. Compounding the problem is poverty. Around 2.5 billion people worldwide have no access to proper sanitation, more than a third of the world’s growing urban population live in slums and as many as 100 million people live in absolute poverty (United Nations, 2008).
Over a billion people are malnourished, a figure that includes one in every four children in developing countries (FAO, 2009a). While we in the developed world can afford to make drastic changes in our lifestyles (even if we may not want to) to tackle climate change, there is an urgent need for people in the developing world to raise their standard of living – and this will mean increases in GHG emissions.
The implications for the developed world are clear. If we are to keep the global concentrations of greenhouses gases in the atmosphere to below 450 CO2e ppm, and if the developing world economies are to achieve a reasonable standard of living, then rich countries, who contribute the bulk of present and historical greenhouse gas (GHG) emissions, need to reduce their emissions by 80 per cent or more (Committee on Climate Change, 2008), with the IPCC’s Fourth Assessment report suggesting that a reduction of up to 95 per cent may even be needed (Gupta et al, 2007). Critically, we also need to be taking steps to reduce our emissions right now; the longer we put off taking action, the harder it will be to keep emissions beneath the 450ppm threshold (Stern, 2006).
Climate change and the role of food
The food chain contributes significantly to GHG emissions, both at national (UK) and international levels. Estimates vary, with ranges given from about 19 per cent (Garnett, 2008) of UK to 31 per cent (European Commission, 2006) of EU total emissions (reflecting, among other things, different methodological approaches), but clearly the impact is considerable. Emissions arise at all stages in the food production cycle, from the farming process itself (and associated inputs) through manufacture, distribution and retailing, to the storing and cooking of food in the home or catering outlet.
At the farming stage, the dominant GHGs are nitrous oxide (N2O) from soil and livestock processes (faeces and urine) and methane (CH4) from ruminant digestion and rice cultivation. Carbon dioxide (CO2) emissions arise from the fossil fuel inputs used to power machinery and to manufacture synthetic fertilizers, albeit to a lesser degree. The IPCC estimates that agricultural emissions account for 10–12 per cent of the global total (IPCC, 2007) and that by 2030 agricultural emissions are projected to grow by 36–63 per cent (Smith et al, 2007). For the UK context, emissions associated with agriculture account for nearly half of the food chain’s total impacts, or around 8.5 per cent of the UK’s total GHG emissions (Garnett, 2008).
Notably, neither the IPCC’s estimates, nor those given for the UK, take into account carbon dioxide emissions resulting from agriculturally induced changes in land use (such as deforestation, land degradation and the conversion of pasture to arable) since these are considered in a separate category.
However, it is clear that these changes are very significantly driven by agricultural production, particularly of some foods, and these add considerably to farm stage impacts. One global estimate suggests that farming-related land use change emissions add a further 6–17 per cent to the total agricultural burden (Bellarby et al, 2008), putting agriculture’s contribution to global emissions at between 16 and 29 per cent of the global total, or as much as 32 per cent once fossil fuel inputs are included. More recently a UK study estimates that if land use change emissions attributable to UK food consumption are included, the contribution of the UK food system to UK emissions rises from around 20 per cent to 30 per cent (Audsley et al, 2010).
Beyond the farm, the bulk of emissions are attributable to the fossil fuel used to process, transport and retail goods, for refrigeration and for cooking. In the UK, these collectively account for just over half of food’s total impacts. Estimates for the developing world have not been undertaken but it is likely that, given the lack of fossil input-using processing and logistics infrastructure, the agricultural stage emissions will, relatively speaking, be more significant.
Greenhouse gas emissions and the contribution of the livestock sector
While the production and consumption of all foods contributes to GHG emissions, it is increasingly recognized that livestock’s contribution to the food total is particularly significant. The vast majority of livestock’s impacts occur at the farm stage, with subsequent processing, retailing and transport playing more minor roles (Berlin, 2002; Foster et al, 2006).
At the European level, an EU-commissioned report puts the contribution of meat and dairy products at about half of food’s total impacts (European Commission, 2006). For the UK, it has been estimated (Garnett, 2008) that the meat and dairy products we consume (including the embedded emissions in imported products) give rise to around 60 million tonnes of CO2e, equivalent to approximately 8 per cent2 of the UK’s total consumption attributable GHG emissions or 38 per cent of all food’s impacts.
Importantly, the figure does not include land use change impacts associated with the production of feedstuffs overseas destined for UK livestock. Livestock account for the bulk of the UK’s total agricultural impacts through the methane that ruminants emit, and through the nitrous oxide emitted both directly by livestock and indirectly during the cultivation of feedcrops. According to the FAO, by 2050 the global production and consumption of livestock products is set to double. This clearly has implications for GHG emissions.
Life cycle analysis shows that ruminant animals, such as cattle and sheep, appear to be far more GHG intensive than monogastrics, such as pigs and poultry (see Table 3.1). This is because the former emit methane during the process of digesting their food.
Since the bulk of the anticipated increase in production and consumption will be met by increases in pig and poultry production, with much smaller increases in ruminant production, this is seen to act as a modifying influence in the growth of livestock-related GHG emissions (Steinfeld et al, 2006). The apparent GHG superiority of white meat to red, and the implications for trends in emissions is, however, complicated by various factors relating to the benefits that livestock bring, as we discuss.
The GHG benefits of livestock production
While livestock production contributes significantly to food-related GHG emissions, to conclude that a vegan agricultural and food system would be preferable is far too simplistic. Livestock farming has been practiced for millennia for good reason – livestock yield multiple benefits, and many of these are environmental. Table 3.2 briefly summarizes the benefits of livestock production and sets them against some of the disbenefits.
For a start it is worth pointing out the obvious: eating will always carry with it an environmental ‘cost’, although plant based foods, on the whole, generate fewer GHG emissions. Meat and dairy products are an excellent source of nutrition, providing in concentrated form, a range of essential nutrients, including energy, protein, iron, zinc, calcium, vitamin B12 and fat. This said, these nutrients can also be obtained from plant-based foods (or, in the case of vitamin B12, by fortification) (Appleby et al, 1999; Key et al, 1999; Sanders, 1999; Millward, 1999) and the importance of meat and dairy products in supplying these nutrients very much depends on where you are in the world and how rich you are.
On the one hand, in rich societies suffering from the health burdens of over-nutrition, the superabundance particularly of excessive fat and energy in fat- and calorie-rich animal products, can be actively deleterious, while a diverse and nutritionally adequate range of plant based foods are widely available. For these people, plant-based foods can provide adequate nutrition at lower GHG ‘cost’.
Among poor societies, however, where meals are overwhelmingly grain or tuber based, where access to a nutritionally varied selection of foods is limited and where there are serious problems of mal- and under-nutrition, keeping a goat, a pig or a few chickens can make a critical difference to the adequacy of the diet (Neumann et al, 2002).
It is also important to note that animals provide us not only with nutrition but with non-food goods such as leather, manure (which improves soil quality and reduces the need for synthetic fertilizers), traction power and wool. If people did not obtain these goods from livestock, they would need to be produced by some other means and this would almost inevitably incur an environmental cost.
Perhaps most importantly, some livestock systems actively contribute to the avoidance of GHG emissions in two ways. At the right stocking density (and this is critical), grazing animals have an important role to play in maintaining and, in some cases, building carbon stocks in the soil (Allard et al, 2007) – although the evidence on sequestration is mixed. Ploughing this land for arable production would lead to the release of GHG emissions.
It is also the case that much of the land used by grazing ruminants is not suited to other forms of food production (for example the Welsh uplands, or the Mongolian steppes). By eating animals that are reared on land unsuited to other food producing purposes, we avoid the need to plough up alternative land to grow food elsewhere. Note that these potential carbon sequestering, land utilization benefits are obtained from ruminant livestock systems and not from pigs and poultry – a benefit that is not captured by life cycle analysis or in the figures presented in Table 3.1, above. Livestock can also play a vital role in mixed crop rotations; by consuming the clover planted to fertilize the soil they give value (through the milk they provide) to what would otherwise be an economically unproductive part of the rotation.
Their manure also helps fertilize and improve the structure of the soil. Livestock farming has another GHG-avoiding role in that livestock consume by-products that we cannot or will not eat. We, by eating animals who have themselves been fed on food and agricultural by-products, are consuming ‘waste’ made edible, and in so doing we avoid the need to grow food on alternative land – a process that could give rise to land use change emissions and require fossil fuel based inputs. The feeding of some by-products to livestock is now limited in the EU by legislation; for example, there has been a ban on feeding pigs catering waste, or swill, of mixed plant and animal origin since 2003 (this ban was introduced in 2001 in the UK), following the outbreak of foot and mouth disease. And of course caution is needed: the feeding of certain by-products to animals can (as in the case of BSE) be catastrophic; in many developing world countries pig farming in peri-urban areas, where the pigs are fed on sewage, can give rise to food safety problems. Moreover, when considering the benefits of livestock for soil carbon sequestration and resource utilization, it should be borne in mind that the gains are highly dependent on the type of system within which the livestock are reared and the scale of the demand for livestock products. At the extremes both of extensive and intensive livestock systems, the benefits tend to be outweighed by the disbenefits.
In extensive systems (such as those found in many parts of the developing world) that do not use additional feed inputs there can be soil carbon losses that result from overgrazing (Abril and Bucher, 2001) – that is, when the number of cattle being reared is greater than the land’s carrying capacity. This is a significant concern in the developing world and it has been estimated that 20 per cent of land globally is degraded (Steinfeld et al, 2006).
Note that the UK is implicated in overgrazing-related carbon losses overseas when our demand for major agricultural commodities (often grown to feed intensively reared British livestock), pushes poor livestock farmers on to increasingly marginal and vulnerable pasture lands where soils are quickly degraded. Moreover, extensive cattle farming systems, such as Brazilian ranching, have a highly damaging effect because they trigger a shift from a very high-carbon sequestering form of land use (forest) to one that sequesters less carbon (pasture) – quite aside from the catastrophic impacts on biodiversity.
Hence the potential carbon sequestering role of livestock depends on good land management, the maintenance of appropriate stocking densities and – critically – on constraining expansion. In extensive systems where the farm animals are reared in climatically or geologically extreme conditions and receive no supplementation at all, they may also suffer from welfare problems.
Intensive systems, such as those found in the UK, present a different set of problems. For a start, while ruminants do graze on grasslands, these grasslands are not always a ‘free’ resource. In all, some 66 per cent of the grassland area in the UK receives nitrogen fertilizer applications (Defra, 2007), and these give rise to N2O emissions. While sheep and some cattle are indeed left for much of their lives to graze on the uplands, they are usually finished on fertilized lowland grass, perhaps supplemented with concentrates – without this extra input, the meat yield would be too low to be economically viable. Moreover, livestock of all types in intensive systems not only consume by-products but also large quantities of cereals that, arguably, could have been eaten directly and more efficiently by humans.
Measured in terms of land area or GHG emissions per unit of protein or calories, it is less efficient to feed grain to animals that we then eat, than it is for us to eat the grain directly. Globally, livestock have been estimated to consume over a third of world cereal output (FAO, 2009b) and the proportion is higher still in the UK (Defra, 2008a). The use of land to produce cereals for livestock ultimately leads to land use change either directly, by colonizing new land, or indirectly, by pushing existing activities (such as pastoral grazing) into new land. The negative impacts of soy, a major input to intensive systems, are particularly striking. While soy-oil has its uses in industrial food manufacture and increasingly as a biofuel, the cake accounts for around two thirds of the crop’s economic value (since it is produced in larger quantities than the oil) (FAO, 2009b) and as such in some years can actually drive soy production. Soy cannot, then, accurately be called a ‘by-product’. Soy farming has major implications for GHG emissions because of its role in land use change and particularly in deforestation.(WWF, 2004; Nepstad et al, 2006; McAlpine et al, 2009). While cattle ranching is the major driver of deforestation in Brazilian Amazonia, accounting for the bulk of direct deforestation, the relationship between cattle ranching and other drivers, particularly soy, is both close and complex. Cattle ranches are often set up to secure land tenure and to maintain cleared land, allowing other more profitable enterprises such as soy to move in (McAlpine et al, 2009).
In the decade up to 2004, industrial soybean farming doubled its area to 22,000km2 and is now the largest arable land user in Brazil (Elferink et al, 2007). Moreover, soybean cultivation not only makes use of land in its own right, but is also an important ‘push’ factor for deforestation by other industries; it takes land away from other uses, such as smallholder cultivation and cattle rearing, and pushes these enterprises into the rainforest (Nepstad et al, 2006; Fearnside and Hall-Beyer, 2007). Additionally, it provides income to purchase land for other purposes, including logging.
Hence while beef cattle are a major direct cause of Brazilian deforestation, the role of soy as a second stage colonizer is significant. As highlighted earlier, the bulk of the projected doubling in the production and consumption of livestock is due to increases in intensive pig and poultry production. Intensively reared pigs and poultry are major consumers of soy. Thirty-two per cent of Brazil’s soy feed was exported to the European Union in 2006/7 and 90 per cent of that soy went to feed Europe’s pigs and poultry (Friends of the Earth Netherlands, 2008); this ‘hidden’ land use cost should properly be added to the emissions shown in Table 3.1.
Moreover, while pigs and poultry in intensive systems may be efficient converters of feed into meat, they rely on cereals and soy – in fact actively compete, through the demand for grains, with land needed to grow crops for humans. As such, farming them in this way is implicated in land use change. Unlike grazing animals, they do not provide the benefit of carbon storage services.
This said, if the projected increase in animal source foods were met by either by increases in extensive or intensive ruminant farming the problem could arguably be worse. The direct land needs of ruminant cattle are large and expansion into forest areas would lead to major soil carbon losses.
As for intensive beef and dairy systems – again, set to grow – these require not only grazing land but also significant cereal and oilseed inputs, which, as noted, they consume less efficiently than do pigs and poultry. As such, high volume, intensive ruminant production would represent the worst of both worlds. We would have a system that emits methane (as well as the nitrous oxide that all animals emit); and that is also dependent on cereals and soy – a double whammy. Expansion of extensive grass fed systems does not, therefore present a solution. To conclude, ruminant livestock can yield carbon storage and resource efficiency benefits but this only takes place in certain extensive systems at certain stocking densities. Once the numbers of livestock are greater than the ability of the land to support them, then the disbenefits, in the form of land degradation (and lower animal welfare) rise to the fore. Similarly, while livestock farming of all types can represent a form of resource efficiency, the volume of by-products available cannot alone feed the sheer numbers of animals that we appear to want to eat. Growth in demand is what turns a sustainable system into an unsustainable system. Hence what emerges when discussing the benefits and disbenefits of livestock systems is that two factors are critical: the type of livestock system, and the scale of livestock production and associated consumption. The right type of system at the right scale is needed to ensure that the benefits outweigh the disbenefits.
Reducing livestock-related GHG emissions: What can be done?
Policy makers in the developed world are increasingly aware of the need to tackle livestock-related emissions. There is now a very considerable and growing body of research examining how GHG emissions from agriculture in general, and from livestock more specifically, might be reduced (Clark et al, 2001; Committee on Climate Change, 2008; Defra, 2008b; Garnett, 2008; Smith et al, 2008).
Broadly speaking, the focus is on efficiency: an approach that takes as its starting point the need to meet growing demand at lowest GHG cost. As highlighted, the key word here is demand. It is projected – and accepted – that demand for meat and dairy products will double by 2050, and while the consumption issue is starting to receive some attention in the developed world, growth in the developing world is taken to be inevitable. Efficiency is taken to mean the production of as much meat, milk and associated products for as little environmental and land use ‘cost’ as possible. We explore the extent to which intensive production achieves its goals and highlight the implications for animal welfare, biodiversity and human health, before setting out an alternative approach.
The efficiency approach
The research literature on livestock GHG mitigation tends to focus on four main categories of action: improving the efficiency of breeding and feeding strategies; managing soils to sequester carbon; managing manure to reduce methane, nitrous oxide and ammonia emissions and (through anaerobic digestion) to produce energy; and decarbonizing energy inputs. Table 3.3 sets these out in more detail.
Approaches b and c relate to agriculture in general. Approach a is specifically livestock related and encompasses a range of strategies. A key element is to manage the feeding regime to achieve an ‘optimal’ balance between carbohydrate and protein – this is to ensure that the food is used by the animal to produce milk or meat rather than being ‘wasted’ in the form of methane or nitrogen losses.
The feed-optimization approach can be combined, in the case of dairy cows, with breeding strategies to increase productivity (by increasing that portion of feed intakes that is partitioned, through metabolic processes into milk) and fertility. To date there has been a strong emphasis on breeding for increased productivity, at the cost of reduced fertility, but there are signs now of greater focus on extending fertility. The fertility issue is relevant from a GHG, as well as from an animal welfare perspective, because a rapid turnover of milkers due to early death or infertility means that energy inputs and greenhouse gas outputs are ‘wasted’ in the process of rearing heifers before they reach their first pregnancy and lactation. Once she has reached maturity, it important to keep the cow milking for as long as possible after this period so that the investment in growth and development pays off and to keep the replacement rate as low as possible.
Parallel strategies for feed production include increasing the productivity of feed crops so that more crops can be grown on a given area of land, again through breeding and fertilizer strategies. Biomass production could form part of the efficiency picture. As rearing livestock on uplands becomes increasingly unprofitable, livestock farmers are leaving the hills – a trend we are witnessing now as a result of the Common Agricultural Policy. An alternative use for the uplands might be biomass production, an approach that contributes to carbon sequestration, and also generates a fuel source. Under an efficiency scenario, most of the growth in livestock products will come from more profitable pigs and poultry, with their higher feed conversion efficiencies.
Note that these feeding and breeding approaches, while ‘efficient’, are inherently dependent on cereals and oilseeds. More grains to feed more animals will mean changes in land use and the CO2 impacts of this are not, as yet, taken into account in the life cycle analyses of the sort that produces the figures in Table 3.1.
Some attempts have been made to quantify the potential GHG savings achievable through a combination of approaches a–d. Most estimates consider the agricultural sector as a whole, as it is difficult to separate out livestock farming given its interconnectedness with the arable sector. However, since livestock contribute to the bulk of agricultural emissions (either through their direct emissions or through emissions generated by the production of feed crops for their consumption), these estimates are indicative of what might be possible for livestock systems too.
It is generally agreed that, for the UK, reductions of up to 30 per cent for agriculture may be technically possible, although what is economically and politically feasible will be significantly lower (Committee on Climate Change, 2008; Defra, 2008b; Garnett, 2008). There do not appear to be any estimates of the potential specifically in developing world countries but some attempts at a global estimate have been made. The IPCC suggests that by 2030 mitigation measures – largely soil carbon management (b, above) – could offset by 70–80 per cent of today’s direct emissions. However, it points out that under a business-as-usual scenario, agricultural emissions as a whole are set to grow by 36–63 per cent (although there are huge uncertainties), due to increases in demand for food in general and for animal source foods in particular. As such, while there may be reductions on a per kg of food basis, there may be no absolute reduction in emissions (Schneider et al, 2007).
The general picture that emerges, amidst enormous uncertainty, is that technical and managerial approaches are not enough. The 50 per cent reduction in emissions per unit of meat or milk will be offset by the doubling in demand. We need, however, to reduce emissions absolutely by 50 per cent by 2050. If the food chain does not play its part in contributing to the emissions reduction, then other sectors of society (housing, transport, energy supply and so forth) will have to reduce their emissions even more to compensate; and these sectors, given a growing global population, face exactly the same sort of challenges as does the food chain. Since technology cannot get us where we need to be, we need to look at changing the balance of foods we consume – and this will include reducing our consumption of meat and dairy products.
Meat and dairy intakes are particularly high in the developed world and historically the developed world is responsible for the bulk of GHG emissions. One equitable approach to consider, then, would be to examine what might happen if people in rich societies were to reduce their consumption of animal products. One possible option would be for the world’s population to converge on consuming what in 2050 people in the developing world are anticipated to consume: about 44kg of meat and 78kg of milk annually.
This represents a 62 per cent and 73 per cent increase on average meat and milk consumption in developing countries today, although this average masks very wide inequities in distribution: average per capita annual meat and milk consumption in Ethiopa, for example, is 8kg and 21kg respectively. For people in the developed world, however, consuming at this level would entail a very substantial change in habits. It would mean that we in the UK would halve the amount of meat we typically eat today, and reduce our milk consumption by an even more drastic two thirds.
Unfortunately, however, action by the developed world alone will not be sufficient simply because the bulk of the projected increase in demand is set to come from the developing world. If we multiply reductions in per capita consumption by the number of people who are projected to be living in the developed and transition countries, and subtract this figure from the overall anticipated demand for meat and dairy products, we obtain a mere 15 per cent overall reduction in projected world meat consumption, and 22 per cent for milk, as Table 3.5 shows.
These figures are strikingly low – they imply drastic declines for the rich and allow for no increase by the poor. Diets low in animal products can be nutritionally adequate but – as highlighted – much depends on what else there is to eat and how equitably it is distributed. Policy makers need to think about developing food and agricultural strategies based on combining food and climate change policies – of prioritizing food security at minimum greenhouse gas cost.
The efficiency mindset as characterized by approach a, above, is not only unable to meet our emission goals but it also considers animals and their emissions simplistically as a problem to be managed in order to meet demand. Issues such as animal welfare, the health implications of increased meat and dairy consumption for the 1 billion of the world’s population who are overweight or obese (WHO, n.d.) and biodiversity losses are to be addressed by other means. Examples include marketing niche higher welfare systems for ‘premium’ customers who demand it, developing (for obesity) low fat food formulations, functional foods, nutraceuticals and exercise programmes and intensifying production on agricultural land so as to create biodiversity havens, or ghettos on the land that remains.
There is an alternative way of thinking, however, which could be characterized by the phrase ‘livestock on leftovers’. Such an approach seeks to work with what animals are good at – making use of marginal land, and feeding on by-products that we cannot eat. It considers what the land and available by-products can sustainably support – and then assesses, on that basis, how much is available for us to eat. It takes land and the biodiversity that it supports as its starting point, and as its ultimate constraint. This mindset considers demand to be negotiable and challengeable.
With this approach livestock can be integrated into a landscape so that they help store carbon in the soil, enhance the biodiversity of local ecosystems and make use of the leftovers from other food and agricultural processes. There will be a need to focus research on breeding programmes that emphasize robustness and flexibility; that improve the ability of ruminants to survive on marginal lands and of all livestock types to respond well to a variable supply of different foods – to cope well with a less nutritionally precise environment, as it were. We need also to consider how livestock can be reintegrated into arable farming systems in the developed world, as part of a mixed livestock–crop rotations and livestock–agroforestry systems.
A ‘livestock on leftovers’ approach need not, and should not, be purist. For example, in many developing world countries, ‘intensification’ may include actions to ensure that cows have something better to eat than plastic bags – and there will be welfare as well as productivity gains from so doing. Options b, c and d outlined in Table 3.3 above will still be key to overall agricultural mitigation.
This ‘livestock on leftovers’ approach is likely to provide us with far lower quantities of meat and dairy than that afforded by intensification – but the system actively helps deal with the problem of climate change, while the efficiency approach is simply geared towards minimizing the damage that livestock cause. A livestock on leftovers approach would form part of an agricultural strategy that takes as its starting point the need to meet nutritional needs, while mitigating agricultural emissions.
A short note on fish
This chapter has focused on only on terrestrial animal source foods and as such has omitted a very significant contributor to human protein intakes: fish. While the volume of fish from capture fisheries has remained fairly stable, aquaculture has been growing at about 8 per cent a year and now accounts for about a third of all fish harvested (and around half of fish destined directly for human consumption) (FAO, 2008). There is a risk that if people reduce their consumption of meat and dairy products, they will increase the amount of fish they eat. While from a GHG perspective, fish on the whole have a lower GHG footprint than terrestrial livestock, this generalization masks wide variation in the relative intensities of different fish species. For example a study by Tyedmers into fuel use in fishing reported a range of fuel inputs to fisheries of 20–2000 litres of fuel per tonne of fish landed, largely becuase of differences in the intensity of fuel use by fishing vessels (Tyedmers, 2004). There are similarly wide differences in aquaculture; the variation in intensity here depends in part on the feed source (particularly the amount of fuel used in the fishing of the wild fish that go to feed the farmed fish) and partly on the inherent feed conversion efficiency of the farmed fish themselves (Pelletier and Tyedmers, 2010). It is also very important to emphasize that a simplistic carbon accounting assessment risks ignoring the very serious broader environmental and ecosystemic issues associated with the fish and aquaculture sectors. In the case of wild fish, just of half of all stocks that have been monitored are now fully exploited; over a quarter are over-exploited, depleted or slowly recovering, with the remainder either under-exploited or moderately exploited (FAO, 2008).
As regards aquaculture, this is associated in some parts of the world with significant environmental problems, including coastal pollution, the destruction of mangrove swamps and the escape of farmed fish into the seas, spreading disease. Carnivorous fish, such as salmon, trout and tuna and omnivores like shrimps that are often reared on a carnivorous diet, are fed wild fish from stocks that may themselves be depleted – and these kinds of fish are the species that have grown most rapidly in popularity.
On the other hand, many forms of aquaculture – including all plant (such as seaweed) and mollusc cultivation, polyculture systems that incorporate these species and many forms of extensive to semi-intensive freshwater finfish production – rely little on marine inputs such as fish meal and could potentially make a significant and sustainable contribution to global food protein supplies (Tyedmers et al, 2007). There is in particular, as yet, unexplored scope for increasing the use of algae and seaweeds, both as feedstuffs and for consumption in their own right. In short, the picture currently presented by aquaculture is mixed but there is great potential for improving the sustainability of the aquaculture sector (in particular in reducing its dependence on wild fish as a feedsource) and, in so doing, providing an alternative to livestock consumption and production.
Conclusions
Our food system faces enormous and difficult challenges. We need to halve food and agricultural emissions by 2050 while feeding a global population that will be a third higher than it is today. We also need to meet these goals within the constraints of what are essentially ethical ‘non- negotiables’: the safeguarding of biodiversity and a decent quality of life for the animals that we rear and eat. We are bound, of course, by the ultimate constraint – land. The projected doubling in demand for meat and dairy products presents a possibly insuperable obstacle. At present technological improvements will not allow us to meet this demand and at the same time reduce emissions to the degree needed. It may conceivably be that we achieve a technological breakthrough, enabling us to meet demand while also reducing emissions – but it is likely that this will come at the expense of animal welfare and of biodiversity. There is, moreover, no guarantee that by producing enough food we achieve food security. Distribution and access are socio-economic, not just biological, challenges. One might argue that a more redistributive approach to meeting the food needs of the most vulnerable will be mindful of the environmental impacts – since it is the poorest who have to live most directly with the consequences of climate change.
By contrast, a business-as-usual approach continues the global trend towards further dependence on energy- and GHG-intensive lifestyles, and the challenge of trying to meet these demands will continue. By 2050, on current projections, the developing world will still, on average, be eating less than half as much meat as people do in the rich world, and only a third of the milk. There is a long way to go before they catch up with developed world levels. Do we assume that ultimately they will want to eat as much meat and milk as we do, and do markets therefore seek to supply these volumes? When is enough enough? Who decides at what level justifiable wants turn into unsustainable greed? We need to start questioning the unquestionable – demand. Time is running out. We have little time left to avert the worst impacts of climate change. We need to start tackling the problems we face – food security, climate change, animal welfare, biodiversity – in an integrated way rather than through the separate, sometimes conflicting strategies that we have today. The vision should be to achieve good nutrition for all at minimum environmental cost, and global policy makers will need to develop fiscal, regulatory and other measures to make this happen. Farm animals can play an important part in achieving this vision, but to do so, the livestock sector needs to understand and work with the strengths and limits of the land and its resources.
Notes
1 The IPCC defines this as ‘over 90% certainty’.
2 Note that the figure is almost the same as the total attributable to agriculture. This results from different methods of quantifying agricultural and livestock emissions and different data sources and different boundaries. However, what is clear (and this is also evident from the UK GHG inventory) is that livestock account for the bulk of agricultural GHG emissions.
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