Discipline: dairy production; Keywords: greenhouse gas, global warming, fossil fuel, methane, nitrous oxide, water use, animal foods, plant-based foods.
The claims and accusations in the campaign have been researched from various perspectives. The response by the author plus associated information is summarized below:
- Greenhouse gas (GHG) implications
Emissions: Agriculture’s contribution in G20 countries are less than 10%, with livestock about 5-6% (in the US it is even less at about 3%). In developing countries, although more as a percentage, the total GHG emissions are low because of less industrialisation. Thus, livestock’s contribution to GHG emissions is comparatively insignificant, if one considers reduction of GHG to limit climate change.
Methane(CH4) emissions from livestock (therefore cattle) are part of the biogenic cycle developed over millions of years with wild herbivores as integral part of the success thereof. In the biogenic cycle atmospheric carbon dioxide (CO2) is utilized in photosynthesis to build plant material (and releasing oxygen as an essential by-product), depositing carbon as building blocks for plant cellulose and other carbohydrates, which provides energy to the grazing herbivore. Although wild herbivores still inhabit the planet in vast numbers in specific areas such as the Serengeti in Africa and parts of North America, the majority have been replaced by livestock (mainly cattle) which are utilised for food. The process of biogenic conversion remains the same whether cattle or wild herbivores. Thus, any argument to reduce cattle numbers because of GHG emissions must therefore also consider wild herbivores, doesn’t it? If the argument wants to include biodiversity, cattle per se is not the culprit, the production system is. Cattle can be farmed with successfully without negatively influencing biodiversity.
Following utilisation of plant material by herbivores (e.g. cattle), part of the plant carbon is utilized and stored in the animal body and the indigested part enters the soil through decomposition of manure. This is positive to soil carbon and soil health. Through the fermentation process of the food, methane is formed and released into the atmosphere. This is where the argument to reduce cattle numbers originates, as methane is a potent gas contributing to global warming. Methane releases into the atmosphere stays active for about 12 years, where after through the process of hydroxyl oxidation becomes CO2 to be entered into the biogenic cycle as described above. Thus, if the release of methane from cattle does not increase for 12 years, the system is in equilibrium and there is no net warming; if the release declines there can be a cooling effect. So, in that sense the argument to reduce cattle numbers is correct. However, cattle methane (as any herbivore) is integral to the biogenic cycle as described; captured fossil methane over millenniums in deep earth, rock and under ice in the pole regions is not. This is released in exploration and utilization of oil and gas. This methane is ‘new’ to the atmosphere compared to the herbivore methane and accumulates because it exceeds the capacity of the biogenic cycle. Methane released in this way should be our primary concern!
Sequestration: Atmospheric carbon (CO2) can be returned to plant roots and soil through the biogenic cycle. The process is called carbon sequestration and is enhanced by grazing of herbivores (cattle), because grazing stimulates photosynthesis. Thus, the more grazing rates are allowed in grazing management, the more carbon is sequestrated, provided that the biomass material doesn’t decrease. Estimates show that carbon sequestration has about 2-3 times the potential to reduce GHG in the atmosphere than does emission reduction strategies. Cattle are essential in carbon sequestration strategies, and in fact this suggests that cattle numbers should be increased rather than reduced to contribute to mitigation of global warming.
To maximise carbon sequestration, many sites in the world used for crop production and even planted forests (e.g. for timber) should be returned to natural grazing (grasslands etc), because natural grasslands through grazers such as cattle sequester carbon even better than forests. This again emphasises the important role of cattle in this regard.
This has very little to do with livestock (e.g. cattle). Nitrous oxide (N2O) has 298 times the warming potential of carbon dioxide, and is therefore a highly potent GHG. Most originates from chemical fertilizers and pesticides which are extensively used in crop (grains, legumes and vegetables) production. Apart from its warming potential, nitrous oxide is now the main pollutant in the atmosphere which depletes the ozone layer. Thus one can argue that crop production should rather be reduced, but the problem is one of wrong production systems rather than crops per se; one should address it with systems such as regenerative agriculture where less or no fertilizers can be used.
- Water consumption:
Statement: A total of 238 litres of water is required to produce 1 cup of milk.
Response by author: Let me test this number by doing a calculation. The modern dairy cow produces about 1.5 litres of milk per kg dry food consumed. She requires about 3 to 4 litres of water to metabolize the kg dry food and if heat stressed another 1.5 to 2 litres of water. This adds up to a maximum of 6 litres of water per kg dry feed with which she produces 1.5 litres of milk, or 4 litres of water per litre (kg) of milk. Not all cows in a herd is lactating, some 25% are dry. By adding their water requirements: 25/75 x 4 = 1.3, say 1.5 litres, the number becomes 5.5 litres water per litre of milk. Water is also used during cleaning in the milking parlour and during processing in the factory. This is in the order of 20 to 30 % of the milk produced. If 30 % is assumed, the number of 5.5 litres increases to 7.15 litres (130/100 x 5.5). This number can be increased to 7.5 litres of water per litre of milk to account for further waste and inefficiencies. Thus for a cup of milk which is 250 ml, the requirement will be 250/1000 x 7.5 = 1.875 litre of water, or ca 2 litres. This accounts for all blue (drinking or fresh) and grey (waste) water. If green water (all water absorbed into the plants that are eaten) is added, which is 90 % of total, the number becomes 100/10 x 2 = 20 litres total water per cup of milk. The calculation can be done in a different way, but it is clear that the number of 238 litres water per cup is an exaggeration and thus unfounded.
- The role of livestock (cattle) in certain parts of the world:
Without going in too much depth, livestock is farmed with in many parts of the developing world because of insufficient water resources to cultivate vegetables and fruit, and because of a number of socio-economic reasons: Inhabitants rely on livestock for sustenance, and cultural and capital reasons, and this will not change. Furthermore, vegetables and fruit cannot be transported to these areas because of transport, storage and packaging cost. The investment potential is also not attractive.
- The nutritional value of livestock food products:
Livestock foods are nutritionally dense with correct proportions to optimise human growth, lactation and health. This is not the case with any one or combinations of foods derived from plants, unless supplemented, which will add to cost. Most plant-based foods are bulky if eaten fresh, contributing to inadequate nutritional value. To overcome this, they must be processed which again contributes to cost. With 4IR technology, scientists experiment with computer-based foods based on vegetable compositions but with animal food tastes, an example being a plant-based beef burger. Whereas these technology developments are exciting from a particular perspective, products will not simulate animal-based foods exactly, because of the unique sequence and contents of animal protein amino acid compositions as an example. This is not to say that it cannot be done, but the cost at least for the foreseeable future will be prohibitive and it will be beneficial to just a small portion of the world population.
Arguments against animal foods based on assumptions in the EAT Lancet report: The study has been shown to be scientifically disastrous and not supported by many scientists in the medical and nutritional fields. The recommendations in the EAT report should be rejected. Apart from that, the concerns of many in the past that animal foods are associated with heart disease and cancer, have been refuted by meta statistical analyses of many publications on the subject. For example the association with saturated fatty acids as being detrimental; there are as many studies showing a positive effect. The problem with many studies in the medical field is that conclusions are based on association (correlation); A is correlated to B, but that does not mean A causes B. If one wants to establish cause and effect you need a negative control; in this case no saturated fatty acids in the treatment which of course is almost impossible in human studies. One aspect that does repeat itself is the association of diabetes with heart disease, and one has seen this now also with Covid-19, where many deaths of diabetes patients are due to heart disease following infection with the virus. Diabetes is a problem of insulin-resistance, which is caused by consistent high carbohydrate (sugar and starch) intake. Therefore, the relationship with heart disease is rather associated with sugar, grains, potatoes etc than animal foods which contain very low amounts of carbohydrate. Of course animal foods in excess can lead to obesity which per se can result in diabetes; thus a quantity problem, not a composition issue.