International Vegetarian Union (IVU)
IVU logo 35th World Vegetarian Congress
'Food for all our futures'

Heriot Watt University, Edinburgh, Scotland
July 8-14, 2002
Hosted by

The Vegetarian Society
of the United Kingdom

Vegetarianism is really good for the environment

by David Pye, IVU Treasurer, VSUK Trustee
Friday 11.30 - 13.30

First of all I must say I am indebted to the excellent UK organization known as ‘Compassion in World Farming’ whose report ‘Factory Farming and the Environment’ published in 1999 has inspired me to do these talks and I would recommend it to anyone looking for further information on this topic.

Energy resources

Energy from fossil fuels is an important natural resources that is heavily used in modern agriculture. A number of studies have been made to estimate the quantities used in intensive animal farming, the evidence points to animal feed production as a major and inefficient user of both water and energy resources.

Now the UK is in principle committed to reductions in the use of fossil fuels as a source of energy, and to increasing energy efficiency to reduce consumption.

Fossil fuel energy is a major input of intensive livestock production systems. Electricity and petrol are used directly by farms and indirectly in manufacture and transport. Energy is needed to fuel vehicles and machinery, to manufacture agrochemicals and veterinary products, to grow, process and transport feed, to build, heat and ventilate farm buildings and to transport equipment, products and wastes to and from the farm.

The production and transport of animal feed is the main use of energy in animal farming. A detailed study of livestock systems calculated the amount of fossil fuel energy that is needed in the industrial production of beef, veal and lamb.

Table 1. Fossil fuel energy input needed for intensive meat production.

Source: Brand and Melman, 1993

Energy input

(M joules/kg live weight)



Lamb & Mutton

Animal feed (production, transport, processing)








Fattening (buildings, equipment, fuel)




Fossil fuel energy is used in various processes involved in producing animal feed and in breeding and maintaining the animals during fattening. The results show that feed accounts for over 70% of the total energy used in producing these meats. Feed takes 90% of the total energy use for veal production. Veal also consumes over twice as much energy as lamb and mutton or beef per kg live weight.

Effect on Nitrogen and the nitrogen cycle

Nitrogen is essential for plants and animals and is an important component of protein molecules. Nitrogen gas is all around us in about 80% of the air we breathe but humans and animals cannot synthesise proteins so we need to eat proteins in the form of plants or animal products.

In contrast, plants can synthesise proteins from their simplest components but they need nitrogen compounds in order to do this. Plants can only use nitrogen after it has been ‘fixed’ as a nitrogen compound such as ammonia or ammonium in the soil. One of the main ways this is achieved is by nitrogen-fixing bacteria in the roots of leguminous plants such as peas and clover.

Plants take up nitrogen from the soil in the form of nitrate. The limiting factor for plant growth is usually the supply of nitrates and, in smaller quantities, of phosphorus and other nutrients. Phosphates are needed by plants and animals for essential biochemical processes such as cell division, energy production and photosynthesis.

The ‘nitrogen cycle’ is the series of natural chemical processes by which nitrogen is ‘fixed’ from the atmosphere into nitrogen compounds. It is then used by plants to make plant proteins and to make animal proteins when animals eat plants, and then returns to plant-usable nitrate. Plant and animal proteins are broken down in processes of excretion or decay and the nitrogen in them forms ammonium which is then oxidised to form nitrate. The nitrates in the soil can then be used by plants again, or they may be ‘denitrified’ in further chemical reactions and return to gaseous forms of nitrogen in the atmosphere.

Artificial nitrogen fertilisers are produced by fixing atmospheric nitrogen by industrial chemical processing, and are usually in the form of ammonium salts such as ammonium nitrate and ammonium phosphate. Human interference in the natural nitrogen cycle has greatly increased both the amount of nitrogen available and its mobility.

Pollution and the Factory Farm

Large numbers of animals concentrated in small areas are causing major pollution problems. As we saw yesterday Europe imports 70% of its protein used for animal feed.

It is also importing large amounts of nitrogen which ends up as an environmental pollutant upsetting the natural nitrogen cycle. Factory farms cause pollution of the environment because the nutrient input to the farm (in fertiliser, feed and manure) is greater than the nutrient output from the farm (in animal or plant products).

Large amounts of organic nitrogen-rich material is imported to animal production units as feed. Nitrogen fertiliser may also be used for growing feedstuffs. Large amounts of organic nitrogen-rich waste (manure, waste feed, dead animals) have to be disposed of. When animals are living and excreting in housing, yards or bare paddocks, there are no growing plants to take up the nutrients from their manure. Although in principle manure can be transported to be used as fertiliser for crops on other farms, in many regions it is not economic to transport manure and inorganic fertilisers are used instead.

Farm animals only absorb and utilise a small amount of the nutrients they eat.

Animal feed is rich in nitrogen and phosphate. Any nitrogen and phosphorus that is not used by the animal for body growth or milk or other production is excreted in faeces and urine. A dairy cow excretes much more nitrogen than she uses in producing milk or body tissue. According to the Journal of Dairy Science one dairy cow excretes 138 kg of N and 14 kg of P in a year. This is estimated to be around 80% of the nitrogen and 40% of the phosphorus in a dairy cow’s diet. Beef cattle, pigs and poultry also excrete between 58% and 78% of the nitrogen in their feed.

Agricultural scientists as well as environmentalists now see the high losses of nutrients from livestock farms as a serious problem. A 1999 report from Holland states that:

‘Nitrogen pollution resulting from agricultural activities has been observed in large areas of Europe and is a major threat to the quality of the European aquatic environment (ground water, surface water and marine waters). Around 60% of nitrogen compounds discharged [into waters] is due to Agriculture and intensive livestock production is an important source of the pollution, owing to an insufficient area of land available to these farmers on which to apply the manure.’

‘This is particularly relevant in regions where pig and poultry production is highly concentrated such as the Netherlands, Belgium, Denmark, Germany, the southern part of the UK, the western part of France (Brittany), the Po valley area of Italy and parts of Catalonia.

Nitrogen surpluses are observed to be most critical on pig and poultry farms as a result of their high stocking density compared to the nitrogen requirements of the available farmland.’

Slurry is a liquid mixture of urine and faeces and is very high in nitrogen and potentially highly polluting to soil and water. Large amounts of slurry production is a feature of indoor housing of animals without straw. Slurry is stored in tanks or lagoons, sometimes under the animal housing, and is used for spreading as fertiliser on fields. Accidental spills or leaks of slurry from lagoons into waterways can cause major pollution and damage to wildlife.

In December 1998 a dairy farm waste lagoon at Holsworthy, Devon in the UK was allowed to overflow into a stream when the lagoon pump was not working properly, badly polluting the river downstream of the farm. In the Bridgerule area of Devon in the UK, in July 1999 a slug of farm waste and slurry pollution moved down the river and removed 85% of the river oxygen. The Environment Agency estimated that around 16 km of the river was polluted and nearly 10,000 fish were killed.

Waste from broiler chicken units.

The total amount of waste that has to be removed from a typical chicken broiler unit has been calculated by a consultant on farm planning applications The daily production of wastes is approximately equal to the amount of feed used. Animals need large amounts of feed to achieve the high growth rate expected of them. In 6 weeks a broiler chick needs 3.6 kg of feed and 6kg of water to achieve a weight gain of 1.7kg. This data were used to calculate total quantities of material to be disposed of or transported from a broiler chicken unit holding 100,000 birds at a time. Quantities are given for a single 8-week ‘crop cycle’of 100,000 birds and for a whole year.

Total outputs from broiler unit containing 100,000 birds, in tonnes,

for one 8-week crop and for one year. Source: Howard, 1998

Type of output

single crop (tonnes)

per year (tonnes)

weight of birds



dry matter



nitrogen excreted



water voided






dead birds removed



water respired



carbon dioxide respired



total wastes to air



The total feed input is estimated to be over 3,000 tonnes per year and the water input is over 5,000 tonnes per year. Total solid and liquid wastes are over 4,000 tonnes per year. Total wastes to air are another 7,000 tonnes per year. The total solid and liquid weight to be removed is over 5,000 tonnes per year, including the weight of the reared chickens. The organic waste to be disposed of from a farm includes dead animals, as a proportion of the animals die during production. A normal commercial death-rate for broiler chickens is 5-6%. For a large broiler house of 100,000 birds this death rate would be 5000 birds per cycle, which would require disposal of more than 32 thousand dead birds a year. Dead chickens are sometimes burned on site, creating additional smells, or may sometimes be left to decay and contribute to litter and dust in the broiler house.


We have seen just a few example of how animal farming is effecting the environment. The intensification of animal farming over the last 30 years has played a fundamental role in the damage that agriculture causes to the environment and to biodiversity. Factory farming’s damage to the environment direct stems from the pollution caused by the confinement of large numbers of animals at high stocking densities, feeding and excreting in relatively small areas of land. A further more far reaching effect comes from the need to produce the feedstuffs for our billions of confined animals world-wide. In order to produce feed for farm animals by intensive farming methods we have polluted water and air, damaged our long-term soil fertility and water resources and caused serious declines in many wild plant and animal species.

Industrially farmed animals are concentrated at unnaturally high stocking densities. They are confined, often indoors, on agricultural operations that are too small to grow their feed or absorb their manure.

Highly productive factory farmed animals need large amounts of protein and energy-rich feed to be provided for them. A dairy cow expected to produce 35 litres of milk per day may eat 4,700 kg of forage and 1,600 kg of concentrate feed in a year.

Factory farming depends on a plentiful supply of affordable feed, produced using fertilisers, herbicides, insecticides and fungicides. Application of nitrogen fertiliser to crops has increased 6-fold in the UK since the 1950s and nitrogen use has increased nearly 7 fold.

Large amounts of cropland are given over to producing food not for people but for confined animals. 95% of world soyabean production is used for animal feed. In the UK, 39% of our wheat, 51% of our barley and 75% of our total agricultural land is used to feed animals. Worldwide one third of grain production is used for animal feed.

Europe imports 70% of its protein for animal feed. A European Parliament report has stated "Europe can feed its people but not its [farm] animals". Much of the feedstuffs imported into Europe come from countries suffering from poverty or environmental degradation.

To produce 1 kg of beef uses 100 times more water than to produce 1 kg of wheat and 50 times more water than to produce 1 kg of rice. Feed production accounts for 70% of the total fossil fuel use in animal farming, for vehicles and machinery, for fertiliser and pesticide production, for water pumping, feed processing and transport.

Animal farming is a major source of the greenhouse gases methane and nitrous oxide. An estimated 16% of all methane production and 80% of the annual increase in nitrous oxide comes from agriculture.

Nitrate fertiliser used to grow animal feed interferes with biological nitrogen fixation and damages soil fertility. Nitrates and phosphates which contaminate the non-agricultural environment cause eutrophication (or nutrient enrichment) of freshwater and seawater which changes the balance of species in the ecosystem. According to the Environment Agency 43% of the phosphate load in freshwater comes from farming. Eutrophication can cause algal blooms which remove oxygen from the water and kill fish and other aquatic life. At least 5 British estuaries have excessive algal growth. The European Environment Agency stated in 1998 that eutrophication "has become a major problem in north-west Europe.

Storage of manure, application to land and disposal is a cause of pollution in areas of intensive animal farming worldwide. In the US, a Senate Committee has estimated that 1.4 billion tonnes of solid manure is produced by farmed animals per year that is 130 times more than the waste produced by the human population.

Ammonia gas is an air-pollutant and contributes to acid rain. It is emitted from manure and slurry. As much as 40% of the nitrogen in manure may be released into the environment in this way.


So here we have it, a catalogue of environmental devastation all caused by the desire to eat cheap meat and the desire to make money by producing cheap meat. How can the committed environmentalist ignore the evidence that agriculture and factory farming is destroying the natural environment.

All this would be clear if the environmentalist took off their eco-blinkers and looked at the evidence before them. The major challenge facing us as vegetarians today is to get the environmentalists onto our side. It is already happening as they become aware of the environmental disaster unfolding before them but we can help speed that process or realization.

So as I said yesterday, lets show the environmentalist that reducing meat consumption or taking up a vegetarian diet is the only certain way of halting the environmental destruction caused by modern animal farming. All the facts are in the vegetarians favour. This is one argument we can’t fail to loose.


It is interesting to speculate on how the countryside would look if we all became vegetarian. Certainly it wouldn’t happen overnight and would be certainly be phased in over a period of some years. Would there still be animals in the fields? I would suspect so. The vast majority of farm animals are locked away in factory farms so if they disappeared we wouldn’t see any immediate visual difference in the countryside although pollution would be greatly reduced. There would still be animals reared for meat but they would be organically and compassionately reared and would command a high price in the shops and probably be sold at specialist outlets.

The supermarkets would cash in on the boom in vegetarian convenience meals and research into alternatives to leather and wool would mean the demand for these products would drop. I also expect that the specialist meat retailers would come under so much increasing pressure from vegetarian activists that they may be forced to cease trading after a few years. The continued demand for wool would mean that we would still see fields of sheep but over time this would decline. Agricultural crops would be in demand so fields of wheat and vegetables would still be around with a consequent rise in market gardens. Demand for imported animal feed would reduce rapidly and this may have an marked effect on third world economies and we have a responsibility here to encourage them to grow more exotic products for export to Europe for the increasing market in unusual vegetables and fruit. We also have a responsibility to encourage those countries to grow food to feed their own populations.

Well that’s it from me I would welcome comments or questions from other vegetarians in the room on either the environmental issues or how they perceive the countryside changing as a result of more and more people adopting a vegetarian lifestyle.

Thank you very much for listening.