Simona Rödlach
This blogpost focuses on the sixth sustainable development goal of the UN; clean water and sanitation. I will try to show, how each and everyone of us can help getting a little step closer to achieving this goal, by simply changing our eating habits.
The Argument
Along with climate change one of the most pressing problems we are facing nowadays as a global population is the supply of fresh drinking water. It is predicted that soon 40% of all countries in the world will face severe water stress. When talking about the sustainability, or more the lack thereof, of the meat-, dairy- and egg industry the main topics discussed are land use and CO2 or methane emissions. What is often overlooked though is the huge amount of fresh water that is used to produce animal products. To produce one kilogram of bovine meat more than 15’000 litres of water are needed. Even eggs and cheese, require a huge amount of water with over 3’000 litres water needed for the production of one kilogram of the food [1]. Plants, in comparison, need much less water to be produced. Potatoes for example only require about 280 litres of water per kg. Figure 1 shows a visual comparison between the water used for different foods:
Figure 1: Comparison of water needed for one kg of food
source: https://www.simplehappykitchen.com/?ref=pnt_how_much_water
But why is it so crucial that we save water?
The freshwater problem
With an ever-growing human population, the demand for fresh water has been increasing rapidly in the last decades and will continue to do so in the future. This population growth, together with an increased water usage per person, will severely reduce water availability per person. The water usage will increase partly because more people need more food and the production of food needs a lot of water. According to a report from the UN, the world will only have 60% of the water it needs by 2030 without significant global policy change. There are already water shortages in many regions of the world, such as North Africa, West Asia or Central and South Asia. One billion people in the world must try to survive without having adequate drinking water [2]. Moreover 90% of all the infectious diseases in developing countries are transmitted from polluted water. This is due to a lack of sanitation and handwashing facilities. Some of these diseases are for example Norovirus and Salmonella. Water shortages do not only threaten us humans and our food supply, they can also severely reduce biodiversity in aquatic as well as terrestrial ecosystems.
Furthermore, there already exist many conflicts as a result of water shortages and difficulties in fairly distributing the world’s freshwater between as well as within countries.
What role do meat, dairy and eggs play in the global water crisis?
Agricultural irrigation is responsible for a large part of the global freshwater use (about 70 to 90%). Most of it is used for the irrigation of crops and pastures used to feed livestock [3]. Additionally, the livestock industry uses fresh water to give to their animals to drink and they need fresh water for slaughtering and processing the dead animals. All in all, this adds up to 29% of all fresh water use of the world. So almost a third of our limited fresh water goes into the production of meat, dairy and eggs.
To put that into perspective, we can look at one of the common measures people tend to take in order to try to reduce their freshwater consumption, namely reducing their showering time by a minute or two every day. With an average showering time of 8 minutes per shower and a freshwater usage of about 75 litres this would save around 19 litres of water per day [3].This, is of course done in good faith, but by choosing a plant-based meal instead of a dish including beef one can safe 1’500 to 3’000 litres of water per meal. So simply by going for the vegan version of one’s favourite burger when shopping in the supermarket or by cooking something different for dinner than you usually would, one can have such a big impact on one of our biggest issues worldwide.
So, how come exactly that the production of animal products needs that much more water than the one of plants?
Livestock directly uses only about 2% of the total water used in agriculture: Farm animals drink about 8.7 billion litres of water per day, or over 3’000 billion litres per year. Another 750 billion litres are needed to cool the animals and wash their facilities. So, the total is about 3.5 trillion litres of water needed directly for the animals. To have a comparison, that is twice as much water as is used by the nine million people living in the New York City area per year.
However, what we need to look at are the indirect water inputs needed for livestock production. They are substantial, mainly because of the water required for forage and grain crops. Each year 760 million tons of grain are fed to livestock worldwide. The cultivation of this grain requires about 25 x 1016 litres of water.
Figure 2: Irrigation of grain source: https://cropwatch.unl.edu/styles/hero/public/images/hero/2017/corn-late-season.png?itok=4RaVLONc
But what about free range?
If cattle, for example, are raised in an open rangeland, 120 to 200kg of forage is needed to produce 1kg of beef. This amount of forage requires 120’000 to 200’000 litres of water per kg, or a minimum of 200mm rainfall per year [4]. So, this only works when there is enough natural precipitation. Otherwise the production of free-range beef needs even more water than “normal”, mass production. Most of the world’s biggest cattle ranches are located in very dry places of the world such central Australia or Texas (US). Therefore, they cannot rely solely on the forage that grows naturally in these areas, and they need to feed their animals with grain and soy as well.
The manure problem
All these animals, bred for the consumption of their flesh and their bodily fluids like milk by us humans, leave waste, so-called manure. This manure lands on the pastures or is distributed onto the fields. Rainwater often carries it downhill, away from the pastures and into waterways. Manure can also leak into the soil. Normally, water polluted by humans must be cleaned in sewerage treatment plants. Manure, on the other hand, contaminates water as well, but farmers are not required to treat it.
One component of manure is Ammonia. Ammonia kills aquatic life at concentrations greater than 2 milligrams per litre. Due to that, wastewater treatment plants need to limit the ammonia concentration in water at 1.5 mg in the summer. However, ammonia concentrations in livestock manure can exceed 10’000 mg per litre.
Ammonium contributes primarily to the pollution of the air, but it can also acidify water, lead to an increased growth of algae plants and to eutrophication. Excessive use of manure can also lead to contamination of groundwater if the water does not lie deep enough below the ground.
Another big concern are all the bacteria and antibiotics, that can get into the waterways and the groundwater through manure. If there are a lot of antibiotics in the water, the bacteria living in the water can get resistant against the antibiotics. In consequence, when wanting to use antibiotics later on to treat an infection in humans, they might not work anymore. Farmers use antibiotics on their animals to treat clinical disease, to prevent and control common disease events, and to enhance animal growth. About 80% of all antibiotics sold in the US are used for livestock [5]. A study from the United States Geological Survey in 2002 that examined 139 streams have found a total of 22 antibiotics. While they did not determine the source of the antibiotics, the presence of antibiotics in rural streams most definitely reflects the antibiotic-laden manure produced each year as there were no hospitals or similar institutions there that could lead to such an abundance of antibiotics in the streams [6].
Conclusion
The world is facing a severe water crisis and it is only expected to get worse, as the demand for fresh water will increase in the future. Meat, dairy and egg products use a lot of water as the animals consume a lot of grain and soy. While the directs usage of water is comparingly small, the indirect use through the cultivation of the feeding crops is huge. Cutting back on meat consumption would save a lot of water and protect waterways and groundwater from pollution caused by manure and antibiotics. Of course, producing more fruits, vegetables, beans, and nuts still would require water, but far less than is needed to produce animal products.
References:
[2]: https://academic.oup.com/bioscience/article/54/10/909/230205
[3]: https://www.forksoverknives.com/freshwater-abuse-and-loss-where-is-it-all-going/#gs.2em6u2
[4]: https://academic.oup.com/bioscience/article/54/10/909/230205)
[6]: https://cspinet.org/sites/default/files/attachment/six_arguments_high.pdf