" 1 hamburger = 3000 litres of water = equivalent to showering for two months" - Cowspiracy
Most of our planet is covered by liquid water. Large ocean basins, lakes, rivers and wetlands all contribute to the vast blue surface covering up as much as 70% of the globe. However, only a tiny fraction of all this water is easily accessible and usable for humans. Almost 98% of the global water budget consists of saline water, which leaves us with only a few percentages of fresh water. Almost half of this freshwater is trapped in ice and snow, and even less is easily accessible. Essentially, this leaves us with only 0.007% of available freshwater for human use.
More and more freshwater resources are put under strain as the world population continues to grow along with a rising demand for water. Even though the total amount of freshwater is increasing on a global level, the spatially and temporally uneven distributions lead to freshwater shortages in several highly populated regions around the world. Up to 4 billion people, of which most live in the developing world, experience severe water scarcity for at least for 30 days a year. The rising demand has been attributed to rising living standards, different consumption patterns, and to the growth of irrigated agriculture.
Globally, up to 70% of available blue water is used in agriculture. Water consumed directly by farmed animals takes up only a small part of the total livestock water budget, whereas a considerable part comes from processing and distributing the end product and, most importantly, from producing feed crops. In fact, at least one third of all water used in global food production comes from feed crop farming for livestock.
The water footprint of animal products is undoubtedly high but not all production systems are the same. Industrial livestock production tends to have a lower water footprint compared to grazing systems because of the generally higher “feed conversion efficiency” in addition to differences in the composition and origin of the feed in production systems. Because of the geographically uneven distribution of freshwater, country specific differences in the water footprint are also relevant. Thus, both feed origin, conversion efficiencies and composition affect the overall water footprint of different livestock products.
Grazing beef cattle is considered the most water intensive product, followed by sheep, pork, dairy cattle and chicken (Figure 1). It takes around 22 000 liters of water to produce only one kilogram of grazing beef and around 10 000 liters to produce industrially farmed beef. For a 200 gram beef burger this would equate to 4400 and 2000 litres of water per burger, which makes the Cowspiracy number of 3000 litres fall in a realistic range. Raising cattle also takes more than three times the land area compared to poultry and pork because of the lower feed conversion efficiency in these large animals. Essentially, to produce one kilogram of beef requires around 8 and 11 times more feed than pork and chicken respectively.
Figure 1. The water footprint of different foods (Mekonnen & Hoekstra, 2010)
Over 90% of the farmed animal water footprint can be attributed to the production of their feed crops which is why the water footprint of animal products is generally greater than that of crop products (Figure 1). Eating a plant-based diet can lower one’s water footprint by as much as up to 30%. Despite the livestock industry's large water footprint, national water policies have generally been focused on developing more efficient water management practices in crop production and feed conversion, instead of addressing the "efficiency in the food system as a whole". For this reason, the water footprint of animal products has been considered "a blind spot in water policy".
Although the large transition to more efficient industrial farming practices has lowered the overall water footprint of animal products, there are underlying problems linked to its efficiency. Industrial farming has contributed to the exponential growth of the global livestock population alongside a range of severe risks on the environment and human health. The expected growth in the demand on animal products will require more freshwater resources which are expected to get more scarce in many regions of the world under current climate change scenarios.
The industrialisation of the livestock industry does not only require vast amounts of fresh water but is also one of the main sources for water pollution. The animal manure produced in "concentrated animal feeding operations" contain large amounts of nutrients such as nitrogen (N) and phosphorus (P). This manure can either be used directly on fields as fertiliser, or sprayed in a liquid form to enhance crop fertility. In addition to animal manure, other sources such as charcoal and mineral substances are used to enhance the efficiency of crop production. The nutrients can travel long distances by entering the water systems through rivers and streams, or through infiltration into ground water aquifers. This pollution might have various different impacts ranging from human health to environmental consequences through contaminated drinking water or eutrophication in the oceans and water systems altering ecosystems which can produce toxic algae or oxygen depleted ocean dead zones.
The livestock industry does play a significant role in fresh water usage and pollution. Many strategies have been proposed to minimise both the water footprint and nutrient flows through developing more efficient water and waste management schemes. But with the expected increase in animal proteins, shouldn't there be a shift in focus on our consumption habits, especially in industrialised countries?
Listen to this short interview I did with Dr Carole Dalin (UCL) on freshwater usage and pollutants linked to animal agriculture.
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