join donate discuss

Livestock agriculture – a story of abuse, environmental damage and threat to human health

Livestock agriculture causes environmental harm, animal abuse and human health issues

Introduction (1, 5, 6, 7)

There are about 22 billion sheep and goats, cattle, pigs and poultry farmed globally at any one time (24) and the treatmentof individual animals has become an increasingly urgent ethical consideration. Also, agriculture (with intensive livestock farming) is the third largest top priority factor affecting the environment according to UNEP (United Nations Environmental Programme) (25). The interconnected effects include climate change, and degradation/depletion of other natural resources such as land, soil, water, biodiversity and forests, as well as substantial energy use.

Indoor farming

Food (along with mobility and housing) is unequitable. One in ten people (16) go hungry while over half our primary food crops like pulses / soybeans, roots / vegetables, and cereals / maize are fed to animals – with the attendant calorie loss known as “feed conversion inefficiency” (80% is lost to make beef (1, 7)). There’s already enough food grown to feed the world population and more, up to the predicted 9-10 billion people by 2050 and more. Some sources say over half our crops go to make animal feed (25). Diverting this food back towards people would improve food security and help fight food inequality.

Intensive farming is a moral outrage for many of us, and a drain on the planet and on the food supply itself (20). Added to this are the facts that red and processed meat (like bacon) have also been identified as carcinogenic (2, 11) – causing colon and rectum cancer, and many other health issues also (17).

There have never been more compelling reasons to switch to a plant-based diet.

Ethical (animal welfare) considerations

The price of meat is less is than it ever has been, and it’s thought we eat about 10x as much meat as our great-grandparents. Meat-eating is predicted to increase by 76% over the next 30 years (7), driven by increases in population, wealth, and changes in demographics – the old eating more meat than the young. There is also a trend for fewer producers with more animals per unit. These units are ever-more closed in, walled and secret with the animals hidden from view or inspection.

We are all animals, and there is an overlap between humans and animals in terms of pain and awareness. A sentient animal is one for whom feelings matter (24) and a strong indicator of this is an animal’s ability to choose between different objects/situations and the ability to learn from experience. There is a moral argument reflected in EU surveys where consumers worry about how the animals are treated, and a moral rights perspective considers non-human animals to have inherent value and is concerned about the treatment of individuals (17).

Factory farming of animals is cruel, sometimes horrifically so, at nearly every stage of the farmed animal’s life and death. Practices that subject a sentient animal to severe or long-term pain, to terror, or to a lifetime of close confinement in a small cage where the animal can hardly move (as happens now to breeding pigs) is unacceptable in the 21st century. It ignores the five needs (or freedoms) granted by UK law to animals (diet, environment, natural behaviour, company for herd/social animals, freedom from pain/distress). If they are unable to express their natural behaviour (such as nest-building, play, or avoiding getting covered in excrement) animals suffer great stress and frustration.

Animal welfare depends on legislation, husbandry and market demand by the consumer – if the consumer doesn’t demand it, it doesn’t happen. The same animal welfare problems linger on although they were identified by the Brambell report in Dec 1965 (27). These include mastitis and lameness in cattle and broiler chickens; reliance on (lawful) mutilations and restriction, and failure of clear labelling which doesn’t allow purchasing to be made based on welfare (26). It is very difficult for the concerned consumer to boycott cruelty.

Currently one of DEFRA’s sub-objectives is the “improved welfare of kept animals” – but its definition depends strongly on farmers themselves, some of whom have a vested interest in keeping costs and inconvenience down. There are also arguments which defend meat-eating: it often uses land that can’t be used for growing crops; and pigs and poultry can be raised on human food waste (15).

However, the emphasis on speed in intensive farming puts enormous strain on the animal’s body (speed to become pregnant, removal of young for abrupt weaning, and then to become pregnant again; speed to grow to slaughter weight, to be slaughtered and processed) (24, 25). Stocking densities relate directly to Animal Health, Welfare and Protection as the drive to stock more animals in less space saves some money but causes misery, disease and death.

Also, the impoverishment of natural resources such as land and water may stimulate human conflict and already has in some parts of the world (14, 25).

Factory farming makes most people consider alternative diets.

Environmental harm

Climate change and greenhouse gases

As the number of animals confined inside increases, so does the requirement to use fertile land to grow their feed.

Livestock are responsible for 13-27% anthropogenic GHG emissions (7, 25). Included in this are the ruinous effects of deforestation. Enteric fermentation during digestion causes ruminants (e.g. cattle or sheep) to exhale methane released by digestive bacteria known as methanogens (30). Methane is 30 x more potent as a heat-trapping gas than CO2 (10). References conflict as to whether grass-fed or grain-fed cattle emit more GHGs and work is being done on feed additives which reduce the methane emitted by cattle during their normal digestive process (3,38). GHGs are also made during fertiliser production (which is used on feed fields) (4), from manure and during the transportation of the animal feed and the animals themselves.

Climate change has been associated with extreme weather events such as floods, heatwaves, water shortages, oceans warming and acidifying, rising sea levels, and melting ice-caps (33, 25). Crop yields may be reduced, and it’s identified as one of the contributors to the modern disease burden by WHO (25). Mitigation scenarios include the devaluing fossil fuel assets, ecosystem maintenance, and changes in livestock, cropping and aquaculture practises (33).


Agriculture expands at the expense of forests, grassland ecosystems, and tree/shrub cover, such that there is replacement of natural land by cropland (7). This is called “land-use change” and causes widescale habitat destruction by land transformation and occupation (25, 30). Destruction of the Amazon rainforest is the world’s largest example of deforestation (14% of world deforestation) driven by the international beef and leather trades. Although rate is slowing the forest is still shrinking. Worldwide deforestation continues at about 130,000 km2 a year.

Feeding grain to cattle (which happened from the 1950s on) greatly increases the land “used” by cattle. It is estimated that 33% of global agricultural land is used to produce animal feed. In the UK, early farmers cleared the land. Now ~70% of UK land is agricultural with ~2% organically farmed.

Land and soil degradation

Animal agriculture can result in long-term loss of natural vegetation and hence biodiversity through habitat destruction and pollution. If the soil becomes “desertified” (just bare barren soil), land is abandoned, and farmers move on to new natural habitats. This soil erosion can result from cropland cultivation (pesticides, herbicides and fertiliser) or over-grazing. Soil deterioration includes loss of fertility, waterlogging, compaction, toxicity or increases in number of pests, increases in salinity or acidity or bearing a toxic amount of manure. Manure can contain antibiotics and de-wormer (also hormones in some countries, although not in the EU).

The consumption of land (loss of habitat) is a primary factor driving wild animals towards extinction.

Water pollution and depletion

Livestock is a major driver for water depletion and pollution (up to 33% of freshwater use in the UK (39)). It has an enormous impact on water use, quality, hydrology and aquatic ecosystems. It leaches nitrogen and phosphorous from manure and nitrogenous fertilisers, also ammonia, pathogens and heavy metals – some of which are present in animal feed so come out in the manure. Water is also contaminated from the processing needed to turn animal products into food, for example detergents and disinfectants, especially from slaughterhouses, tanneries and the dairy industry. Nutrients (from fertilisers and animal manure) discharged or run off in quantity can produce dead-zones in freshwater or at sea by the process of eutrophication.

The water footprint of beef per g of protein is six times larger than for pulses. Butter has a lower water footprint than for oil crops, but all other animal products have high usage compared with plants (22). 98% of the water used in producing meat and animal products is also used to produce their feed but fresh water is used for drinking and servicing (e.g. pen washing).

Air pollution

Direct air pollution comes from the treatment of manure which is generally collected from factory farms in lagoons or slurry pits. It is sprayed into the air (“volatisation”) and spread on fields. A point source like a factory farm produces a lot of manure with pigs contributing the most, followed by cattle. As previously stated, this gives off GHGs (nitrous oxides and methane) and releases nitrogen oxides and sulphur dioxide causing acid rain to form in the clouds. Air pollution is one of the contributors to the modern disease burden identified by WHO (25) and it harms human health, mainly by exacerbating or causing asthma and respiratory disease. Agriculture also releases ammonia, as manure or nitrogen fertiliser is applied to the land. This happens primarily in spring.

Loss of Biodiversity

Biodiversity is essential to life, food and agriculture. It is the variety of life, measured in 3 dimensions (genes, species and ecosystems). Recent extinctions far exceed the background rate of extinction seen in the fossil record by 50 to 500 times, so biodiversity is under severe threat. Biodiversity underpins every aspect of food production from domesticated plants and animals. So-called “associated biodiversity” supports food production by providing services such as pollination, pest control, soil formation and maintenance, carbon sequestration, purification and regulation of water supplies, reduction of disaster-threat by increasing resilience, and the provision of habitat for other beneficial species. We don’t know enough about this foundation of our food system – for example 99% of bacteria and protist species remain unknown (30). Wildlife can be seen as a threat to livestock (for example as competition, via predation, or as disease reservoirs or transmitters [as is the case for badgers and bovine TB]) and re-wilding can be seen as a waste of land (8). Other pressures on wildlife include hunting for leisure or trophies, meat (such as bushmeat) and body parts (e.g. for Traditional Chinese Medicine).

It is estimated that 18-35% of all species could be threatened by irreversible climate change. Livestock-induced climate change (11) combines with livestock-induced habitat erosion to aggravate biodiversity loss. Deforestation and land-use change combine to degrade and fragment habitat which is considered a major threat to wild species (25). Other factors include the introduction of invasive alien species (for example the livestock themselves, their diseases, or their food plants) (7,25, 30). There is also overfishing to produce fishmeal for livestock – in 2004, fishmeal for pigs and poultry represented 24-30% of the fish caught (25). Other problems impacting biodiversity include pollution from manure and growing feed (including drugs, hormones, nutrients, pesticides and herbicides). There has also been a loss of agricultural diversity - from 5000 different plants we now use less than 20 species, and 90% of animal-derived food comes from 14 domesticated mammals and birds (7).

We can see that high levels of production (crops, livestock, and fish) have come at the cost of major disruptions to terrestrial and aquatic ecosystems.

Human health issues (2, 7, 10, 36)

Farming or keeping groups of animals has been implicated in the history of human disease (36). Diseases which cross to us from animals are called zoonotic diseases. Measles for example is thought to have arose from a rinderpest-like virus of sheep and goats; smallpox may have resulted from camel domestication; and whooping cough may have jumped to us from sheep or pigs. Leprosy may have originated in water buffalo, and human influenza may have only started about 4,500 years ago with the domestication of waterfowl. Rhinovirus which causes the common cold may have come from cattle. In modern times we see outbreaks of diseases which have their origin in intensive farming – swine flu, variants of BSE, multi-drug resistant bacteria (such as a strain of Salmonella), bird flu – even AIDS is thought to come from people eating chimpanzees.

Antibiotics as livestock growth promoters have been banned in the UK since 2006, but they are still used for routine medication of large numbers of animals at once (19). A human health crisis looms as resistance to antibiotics is spread between pathogenic organisms by plasmid DNA, and resistance is selected for by the overuse of antibiotics. For example, MRSA (meticillin-resistant Staphylococcus aureus) and some types of gonorrhoea are now resistant to treatment.

Processed meat (such as ham, bacon and salami) causes colon and rectum cancers. It is classified in Group 1 “causes cancer” by IARC (International Agency for Research on Cancer) and Cancer Research UK. Pork, beef and lamb have been classified as “probably cause cancer”. In the USA there are already hard-hitting adverts urging people to give up meat such as bacon for health reasons (2, 9, 11). It’s been shown that vegetarians have a 40% less chance of developing cancer and a reduced risk of developing autoimmune diseases like diabetes. Meat, haem iron, nitrates and nitrites from both processed and unprocessed red meat are associated with increased risks of all-cause mortality (32) especiallyfrom cardio-vascular disease, or stroke. Eating plant protein is associated with lower all-cause mortality (31).

Meat also carries a number of well-known health risks such as tapeworm and threadworm. Food poisoning that could come from meat includes Campylobacter, E. coli, Salmonella, botulism, viral diseases, water-borne pathogens like Giardia and cryptosporidium, and BSE/CJD. There is a concern around feed formulations which include animal tissues, arsenic and heavy metals – the feed allowed for pigs, poultry and non-cattle include cattle tissue under 30 months, used poultry litter and restaurant plate waste. There are also occupational health risks and risks for nearby communities (23).

The industry carries the risk of psychological harm and trauma to people working in slaughterhouses. There can be a tendency to de-sensitisation, brutality and even sadism (personal communication). This is made worse by the pressure of piece-work, driving slaughterers to kill as many animals in as short a time as possible and showing rage and impatience if an animal tries to resist or escape.

A move towards plant-based diets will drive down animal abuse, climate change, land, soil, water and air degradation, biodiversity loss and the human health risks mentioned above. Some farms have already moved for various reasons (18, 37).

Non-animal-based lifestyles

Cruelty-free lifestyles involve making careful personal choices about every aspect of life not just diet, including clothes, shoes, entertainment and personal care products. There is avoidance of animal products such as skin or fur, live-plucked feathers or angora, or of musk/oils in perfume. It’s not always easy to make an obvious choice, and many choices are a compromise. Bamboo, flax (29), organic cotton or hemp products (28) may be appropriate. More information is available on specialised websites (12, 34, 35).

Moving to increasingly plant-based lifestyles through research, education and economic reform

Research Ideas

Type of research



Into all aspect of the meat industry

On-farm, University and wider groups (e.g. UN)

Medical schools

Commercial research

Continued research into all aspects of the meat industry is needed to fully explore the ramifications of meat-eating on the health of people and wider effects on the world


Into plant-based diets

Catering schools, University and wider groups

Medical schools

Commercial research

Research into the health effects of plant-based diets (17).

Continued research into sexing hen’s eggs


Commercial research

Sexing the chicken by scanning for a “male-identifying” wavelength in blood vessels in the egg might stop the practise of killing the male chicks (13).


Into animal behaviour

University and wider groups

Share results worldwide

Research is needed into the sentience and natural behaviour of our food animals (mammals like cattle, sheep, goats, pigs; and birds like ducks and chickens) to properly assess the harm inflicted on them (24).

Into new plant-based foodstuffs

University – PhD studentships and wider groups

Commercial research

Continued research is needed to find more meal substitutes which are available, inexpensive and convenient and also novel plant proteins (e.g. lupine).


Possibly into cultured meat

University – PhD studentships and wider groups

Commercial research

At present it is cultured in foetal calf serum nutrient broth - undesirable.

Into non-animal products

University – PhD studentships and wider groups,

Commercial research

Learn from the societies around us

Continued research is needed to bring non-animal materials forward e.g. environmentally-friendly organic cotton, flax, hemp, bamboo.

Into workable policies

Civil service, University – PhD studentships,

Commercial research

Learn from other societies

Work is needed that assesses the needs and conditions of people affected by any proposed project / stakeholders (e.g. those with related livelihoods) and research the legal and administrative framework.

Into challenges around plant-based eating

University – PhD studentships,

Commercial research

Research into the risks, socio-cultural, economic, historical, institutional and political context need to be carried out (for example explore divides around religion, and around local and central government).

Education Ideas

Type of education





CIWF and other NGOs, libraries, newspapers, online resources, country-wide health education methods, country-wide information methods

This will lead to a personal/consumer choice, reducing the saleability of meat (we will be buying less) and transitioning to a plant-based diet and lifestyle. In developed countries there is already a decline in animal-derived products purchased due to health, ethics and a loss of trust in the sector. Slip-back will be prevented if there is good affordable plant-based food made easily available.

Education and experience of animals (their feelings), animal ethics, food and farming in the UK. Gardening  and wildlife classes.

Schools/placements as part of national curriculum

82% of (~1300) survey respondents said they knew a little or nothing about farming (25).


e.g. about honeybees and wild pollinators (30).


Education about the origins of meat and meat animal’s food

Schools/placements as part of national curriculum

As part of learning about farming. Include the fact that plant food which is non-seasonal, grown in heated greenhouses or transported by plane may have as large a level of emissions as meat (15, 25).


Education about the effect of meat-eating on the environment and how to eat healthily with less meat

For the general public, and schools as part of national curriculum. For decision-makers and policy-makers.

Make the environmental connection with diet (17)

Include plant-based cooking lessons and training for professionals

Schools as part of national curriculum and cookery schools

“New meanings and competences around preparing and eating pulse-based dishes are needed.”

“Vegetarian day” in schools

Schools as part of national curriculum

as in the Finnish study 2013 (21).

Promote plant-based diets and teach that plant food can be equally nutritious.


For the general public, and schools as part of national curriculum. For decision-makers and policy-makers.

There could be government promotion/advertising schemes which relate to health and promote plant-based diets – these could be in national dietary guidelines and cooking programmes with celebrity chefs.

Animal body parts and products have all 8/9 essential amino acids…whereas most vegetarian sources have to be mixed to get all 9 (rice and beans for example).  Additives (such as iodine) are put in animal food so the animal product has the additive in. Plant based diets need to ensure uptake of certain nutrients.

Programmes to learn from ethnic vegetarian or historical diets


Schools as part of national curriculum and cookery schools


Legal requirement for restaurants to offer plant-based choices,

Cafés, bars and restaurants

Maybe this could be enforced on the basis of discrimination, but perhaps the commercial drive will be sufficient.

Training programme for farmers and people looking after (or in contact with) stock

Educational institutes

Stock keepers and farmers to be educated and trained to a high standard in animal welfare and animal behaviour. Giving an animal a life worth living requires good husbandry, considerate handling and transport, humane slaughter and, above all else, skilled and conscientious stockmen, which should be defined by an independent body (26).



Change emphasis from productivity to sustainability and move away from animals

On-farm training, adult education courses, part of agriculture qualifications


Policy/economic measures encouraging a move to reformed farming

This is a mix/sequencing combination of stick and carrot, brought about by changes in legislation trying to establish a more benign policy framework with nature. In the past this has suffered from market failure, and policy failure due to conflicts of interest. Decisions should be taken at the lowest relevant organisational level – this is very important as changes have to be planned with the people making the changes.

“Long shadow” (7) supports the need for increased intensification – which is unacceptable because of animal cruelty. It’s a half-hearted measure to tackle the problems generated by livestock and will only slightly slow the rate of destruction. Increased intensification is unnecessary because a move towards plant-based lifestyles means less livestock will be needed, not more.




Match CAP (or copy CAP) payments to the “environmental and animal good” achieved.

National government

Examples are abolishing factory farming and going organic; purifying land water and soil; re-wilding and reforestation with measured increases in biodiversity; and/or switching completely from any meat production. There will also be a concomitant reduction in meat-related charges.


Support farms in transition

National government

As they move to agroforestry for example.

Look after the people involved with re-training and re-employment

Local and national government schemes

The livestock trade is important in terms of employment and contribution to GDP – there’s no reason why moving towards plant-based should stop this. Food plants are grown on farms after all.


Fix animal welfare standards for all animals – do not exclude farm animals.

Consultative legislation by government/EU

The government should act as the guardian of farm animal welfare, with minimum standards applied to define “a good life” or “a life worth living” to the animal itself not just to the farmer. This will mean factory farming is abolished. Independent animal inspectors should have authority, and there needs to be enough of them. Public/independent surveillance. No mutilations except anaesthetised castration in line with Shelter principles. Acknowledge animal rights.

Fund animal welfare organisations

Local and National government budgets

So that they can have paid staff for example.

Improved labelling

Legislation by government/EU

To allow educated / informed choice of food with approval and verification of marketing claims about higher welfare standards.


Reliable trustworthy certificates of production

Legislation by government/EU/NGOs

Again, to truthfully guide consumers.

Prohibit meat adverts unless they warn of side effects and promote plants.

Legislation by government

A similar campaign as was done for cigarettes and seat-belts

Promote citizen’s food production

Funding by local and national government

Non-animal, plant-based.

Nationalisation of the food production chains

Legislation by government

To prevent important issues being side-tracked by commercial interests. As long as there is profit in food production, there is temptation to overlook abusive or damaging practice.

Imports are subject to the same standards


Legislation by government

Do not allow good practise in the UK to be undercut by cheaper imports with lower standards.

A meat tax

Legislation by government

Problematic as taxing food may be felt as unfair. It is extremely important to prevent food price rises across the board.


Reduction of state subsidies


Legislation by government

For on-farm feed and diesel for example.

“polluter pays, provider gets”

Legislation by government

Apply the principle with an automatic levy for clean-up of all the environmental harm to do with raising animals. Apply the charges to the individual businesses such as tanneries/dairies, for the pollution they cause. This could be done step-wise to give them time to change. It could be desk-calculated according to number of animals. At the moment livestock is subsidised by the environment with provision of waste sinks and natural resources like water.

Prohibition and fines for antibiotic use



Except for individual animal treatment in accordance with the Animal Welfare Act 2006.

Fines for overuse of nitrogen fertilisers and manure on land.



Maybe can be worked out at the desk according to acreage (how much bought/how much needed).

Prohibit the use of sticks and goads.




Will have far-reaching consequences for example horse-riding, so this needs to be carefully defined and thought through.


There have never been more compelling reasons to switch to a plant-based diet. The callousness of factory farming alone makes most people consider alternative when they learn about it. We now know that high levels of production of factory farmed flesh has also come at the cost of major disruptions to terrestrial and aquatic ecosystems. Animal agriculture contributes to GHGs; deforestation; land, soil, water and air pollution, depletion and degradation; loss of biodiversity; and human ill health.

A move towards plant-based diets and lifestyles will not only help to protect animals but act as a brake on our personal and planetary charge towards destruction.


1. Monbiot G (08/06/2018) “The best way to save the planet? Drop meat and dairy.” The Guardian.

2. Gocfray HCJ et al. (2018) “Meat consumption, health and the environment” Science 361.

3. Turner J. (2017) “Grass-fed cows won’t save the climate” posted in Science. doi:10.1126/science.aaq1116

4. Mole, B (2014) “Fertilizer produces far more greenhouse gas than expected” ScienceNews.

5. Packham, Chris (2019) “I did Veganuary and now I’m staying vegan” Sun 3 Feb 2019, The Guardian.

6. Compassion in World Farming (not dated “Vision for fair food and farming”)

7. Steinfeld H, Gerber P, Wassenaar T, Castel V, Rosales M, de Haan C (2006) Livestock’s Long Shadow – from the Food and Agriculture Organisation of the United Nations.

8. Tree, Isabella (2018) “Wilding: The return of nature to a British farm.” Picador, AISN B07771D35D


10. “A more potent gas than carbon dioxide, methane emissions will leap as the Earth warms”

11. Thomas CD et al (2004) “Extinction risk from climate change.” Nature 427, pp145-148




15. Carlsson-Kanyama A and González AD (2009) “Potential contributions of food consumption patterns to climate change” Am J Clin Nutr (suppl): 1704S-9S.

16. Gocfray HCJ, Beddington JR, Crute IR, Haddad L, Lawrence D, Muir JF, Pretty J, Robinson S, Thomas SM and Toulmin C (2010) “Food security: the challenge of feeding 9 billion people.” Science 327, pp812

17. Vinnari M and Vinnari E (2013) “A framework for sustainability transition: the case of plant-based diets.” J Agric Environ Ethics (2014) 27 pp 369-396.



20. Pluhar E, (2010) “Meat and morality: alternatives to Factory Farming.”

21. Lombardini c and Lankoski L (2013) “Finnish study - mandatory veg day” J Cons Pol 36(2) pp159-178.

22. Mekonnen MM and Hoekstra AY (2010) “Water footprint of crop and animal products: a comparison”.

23. Walker P, Rhubart-Berg P, McKenzie S, Kelling K and Lawrence R S (2005) “Public health implications of meat production and consumption”. Public Health Nutrition 8(4), 348–356.

24. Turner J (2006) “Stop – look – listen. Recognising the sentience of farm animals.” A report by Compassion in World Farming Trust, updated version.

25. UNEP (2010) Assessing the Environmental Impacts of Consumption and Production: Priority Products and Materials, A Report of the Working Group on the Environmental Impacts of Products and Materials to the International Panel for Sustainable Resource Management. Hertwich, E., van der Voet, E., Suh, S., Tukker, A., Huijbregts M., Kazmierczyk, P., Lenzen, M., McNeely, J., Moriguchi, Y.

26. Farm animal welfare in Great Britain: past, present and future (2009) by the Farm Animal Welfare Council.

24. Welfare of livestock (Brambell Committee Report)



30. FAO. 2019. The State of the World’s Biodiversity for Food and Agriculture, J. Bélanger & D. Pilling (eds.). FAO Commission on Genetic Resources for Food and Agriculture Assessments. Rome. 572 pp. (
Licence: CC BY-NC-SA 3.0 IGO.

31. Song M, Fung TT, Hu FB, Willett WC, Longo VD, Chan AT and Giovannucci EL (2016) “Association of animal and plant protein intake with all-cause and cause-specific mortality.” JAMA Intern Med 176 (10)

32. Etemada A, Sinha R, Ward MH, Graubard BI, Inoue-Chou M, Dawsey SM and Abnet CC (2017) “Mortality from different causes associated with meat, heme iron, nitrates and nitrites in the NIH-AARP diet and health study: population based cohort study” BMJ 1957

33. IPCC (Intergovernmental Panel on Climate Change) (2014) “Climate Change synthesis report, summary for policymakers”



36. D’Silva J and Webster J (2017) 2nd edition “The Meat Crisis” ISBN 9781138673281 Earthscan Food and Agriculture, Routledge, Abingdon, Oxon OX14 4RN.


35. Machado L, Magnusson M, Paul NA, de Nys R, Tomkins N (2014) “Effects of marine and freshwater macroalgae on in vitro total gas and methane production.” PLOS ONE 9(1), e85289.

39. Kowalski M, Waylen C, Cist S, Lynn S, and Garrow D (Waste and Resources Action Programme) (2011)