How much water for 1 kg of meat?
It is often said that 15,000 litres of water are needed to produce 1kg of meat. This is an example of a shock statement used to make good headlines, but the calculations are too often misunderstood and misquoted. With more than 90% of water consumed by livestock being ‘green water’ coming from rainfall, scientists calculate that 1kg of beef would remove around 50 litres of fresh water.
This figure was first released in 2002, when the “water footprint” concept was established, following the growing popularity of the ecological footprint indicators. Arjen Hoekstra, whilst working at the UNESCO-IHE Institute for Water Education, created the water footprint as a metric to measure the amount of water consumed and polluted to produce goods and services along their whole supply chain. Interest in the water footprint increased after its introduction in academic literature. The Water Footprint Network is working on harmonising and promoting the “water footprint” concept.
The water footprint is an indicator of freshwater use that looks not only at the direct water use of a consumer or producer but also the indirect water use. It includes actually “three types of water sources”: blue water, which is the surface or groundwater sourced water consumption by the animals and the irrigation; grey water, which is the water used to depollute the effluents and recycle them; and green water, that is water coming from the rainfall.
Livestock’s water footprint is made of 93% “green water”. It is essential to look at the structure of the water footprint. Regarding livestock average water consumption, more than 90% is green water from rainfall captured in the soil and evaporated by the plants, which returns to the water cycle. This would happen with or without farm animals.
The green water part of these cycles does not reflect the net water consumption for animal production. Real water shortage may only be based on blue water. If green water is taken out of the calculation, the scientific community considers that 550-700 litres are needed to produce 1 kg of beef, including grey and blue water. According to the French national research agency, INRA, 1kg of beef would remove around 50 litres of ‘actual’ (blue) water from the cycle.
Using the same approach, one can estimate that pork meat would require 450 litres, chicken meat 300 litres, eggs 244 litres, and milk 86 litres. To quote the conclusion of the academic publication Animal Frontiers, “Water is a precious resource that must be conserved globally by all sectors of the economy, including agriculture and thus livestock farming. Tools such as the water footprint and LCA are available. Still, policymakers’ interpretation must be refined” conservation of water is necessary, but refinement of the data is required for actual measurement of consumption.
Agriculture accounts for 92% of humanity’s freshwater footprint, and almost one-third of this relates to animal products. This statement coming from a 2006 FAO report “Livestock’s Long Shadow: Environmental Issues and Options”, which is often reported, is very often also misunderstood, and indeed the report was revised at a later date. If you remove rainfall from the calculation, scientists estimate that livestock industries consume 8% of the global freshwater supply.
Its true meaning and the methodology used to calculate this figure remain unknown. This is why it is essential first to understand the concept of the “water footprint” to estimate the real impact of livestock. Livestock uses one-third of all water resources, including green, grey and blue water. Considering blue and grey water that could compete with fresh water consumption, it is estimated that livestock industries consume 13% of the global water supply. Most of that water is used for intensive, feed-based production. The underlying question is the issue of a potential water resource use competition between livestock production and other human activities.
The world contains an estimated 1,400 million cubic km of water. However, “freshwater resources” are limited. Only 2.5% of all water resources are fresh water, and only 0.003% of this vast amount, about 45 000 cubic km, could be used for drinking, hygiene, agriculture and industry. The rest is locked up in glaciers, permanent snow, or the atmosphere. Moreover, not all of this water is accessible because part of it flows into remote rivers during seasonal floods.
Global water demand is expected to increase significantly in the future, by 50% between 1995 and 2025, especially in developing countries. Not only because of a larger human population but also because of overall increases in industrial production and human affluence, which leads to greater consumption of energy, consumer goods, and food, especially animal products. This increase in domestic, industrial, and agricultural water use is expected to expand the areas affected by water scarcity.
Livestock production and water scarcity should be assessed at a local level. There is not a global water shortage as such, but at individual countries’ and regions’ levels, the problem of water scarcity would need to be tackled. No evidence exists that the presence of livestock is related to the risk of water scarcity. For example, there is little overlap in France between regions with high livestock density and those with water-availability problems in summer, some of the latter being areas with irrigated crops.
Global models are in the early stages of development and do not distinguish between developing and developed countries or their production systems. In some regions, especially developing countries, animals are not used solely for food production but also to provide draught power, fibre and fertiliser for crops. The multiple dimensions of livestock production are not accounted for when considering the water consumption per kilo of product.
In addition, animals use crop by-products that would otherwise go to waste. Water usage for livestock production should be considered an integral part of agricultural water resource management, considering the type of production system, if grain-fed or mixed crop-livestock, and scale, if intensive or extensive. Also, the species and breeds of livestock and the social and cultural aspects of livestock farming in various countries should be considered.
Improved farming practices could help to reduce livestock’s footprint. Still, in Europe, a narrow margin exists when considering improving direct water consumption by the livestock sector, as systems are already well optimised. For ruminants, total water intake is between 3.5 and 5.5 L/kg of dry matter. The greater the water content of the feed, the less drinking water they require. For example, with early-stage fresh grass as feed, animals do not require drinking water. Increasing the proportion of fresh grass or silage in the diet thus decreases drinking water intake.
The main room for improvement to avoid local water shortage risks lies in decreased irrigated feeds. In this direction, several options exist, ranging from using plants requiring less water or selected for their improved genetics to enforcing agronomic practices in fields by farmer feed producers. Livestock can also positively influence water resources. For example, animal use of marshes damages biodiversity less than draining marshes to convert them to agriculture. All these things must be considered before claiming that livestock farming is the primary cause of water waste.