Well, it’s not technically a secret, but not many people are aware of just how much water people use every day. We consume a lot more water than we can imagine, and we need to do something about. Water is a finite resource, meaning that there is a limited amount of water available on the world. Oil is another example of a finite resource, we are going to run out of it eventually, but there are many alternatives for oil, including a variety of renewable energy sources, such as nuclear power, solar power, bio-fuels and more. You probably think, well I don’t use that much water, I turn off the tap when I brush my teeth, but most of the water you consume everyday is used in the production of the goods you consume, and this is called the virtual or embedded water footprint.
Water is hidden in just about everything we use every day, cars, clothing, food. The average British person drinks between 2 and 5 litres per day, and then around another 145 litres is used for cooking, cleaning etc. Doesn’t sound like too much, does it? In reality, the overall consumption is around 3400 litres per day. So where is this figure coming from?
The hidden water of daily life refers to embedded water, which means the amount of water necessary to produce a product. To grow the coffee beans for just one cup of coffee, 140 litres of water is needed. A pair of jeans? 11,000 litres. A new car? Around 400,000 litres. Now it’s not everyday that you buy a new car, but you do eat every day, and around 65% of your virtual water footprint comes from food. Have a look at this: https://waterfootprint.org/en/resources/interactive-tools/product-gallery/ to see how much water is required in the production of food, it’s quite surprising!
Here’s an image looking at the water footprint of certain foods, but not many people can eat 1kg of chocolate at once! McDonald's sells around 25 burgers per second. First, that’s a lot of burgers! But then, let’s think, to produce just the meat of one Quarter pounder, in France a Royal, requires around 2,900 litres of water, not even including the amount required for the bread, cheese etc. That equals, just from McDonald's meat sales, 28 million cubic metres of water per day. Remember when I said water is a finite resource, well maybe we should consider whether it’s going to good use!
Different countries
It’s important to remember that this figure does vary from country to country, producing a kilogram of oranges in USA requires around 175 litres of embedded water, but in Australia this figure is over triple, mainly because of differences in climate, irrigation use, production techniques, transportation, technology and more. Additionally, most of our water footprint is water that has been imported, for example, around 70% of the UK’s water footprint is external, meaning that most of the water footprint is from products that have been brought into the UK. So in reality, we’re not using much of our own water, but taking water from other countries, often water-scarce countries, for our benefit.
Types of embedded water
There are three main types of embedded water, green, blue and grey.
Green water footprint:
Water from precipitation that is stored in the root zone of the soil of plants. It is particularly relevant for agricultural, horticultural (vegetables and fruits particularly) and forestry products.
Blue water footprint:
Water that has been sourced from surface or groundwater resources and is either evaporated, incorporated into a product or taken from one body of water and returned to another, or returned at a different time. Irrigated agriculture, industry and domestic water use can each have a blue water footprint.
Grey water footprint:
The amount of fresh water required to absorb pollutants to meet specific water quality standards. The grey water footprint considers point-source pollution discharged to a freshwater resource directly through a pipe or indirectly through runoff or leaching from the soil, impervious surfaces, or other diffuse sources.
Green water is often overlooked more than blue water, because it cannot be extracted and seen, because it is stored in the soil. Most of the world’s crops are grown using only green water, and is more efficiently used than blue water, because in order to withdraw blue water, a large amount of energy is needed. Only 16% of crops are irrigated, and this small percentage consumes 70% of all global freshwater withdrawals (blue water). Additionally, very little irrigation is efficiently done, meaning we waste a lot of water.
What can we do to better manage our water usage?
The best way to manage our shared water resources, and the only way that embedded water can be reduced in the production of foods can be reduced, is by maximizing the use of green water, which is what plants do best on their own, and then sparingly using irrigation where absolutely necessary, using blue water efficiently and responsibly. This may also include only growing crops where they thrive best. For example, rice is grown in water, and rice is grown in California for example, which doesn’t receive much rain, this means that a large amount of irrigation is needed.
Calculating your own water footprint
Curious about your own water footprint? On the left there is a graph showing the average water footprint in litres per person, per day in France. Here is a link to calculate your own, how do you compare to the national average?
What a great article! I had no idea that the production of one kg of chocolate required 24,000 litres of water. Thank you for introducing me to the types of embedded water; I had not idea that existed. And thanks for the link to calculate our water footprint- it was very interesting and kind of scary.
Really great read Lois. This issue of virtual water is certainly now getting more publicity than ever before. Its link to meat production is now well known and people are increasingly aware. Perhaps a factor in increasing numbers turning to a more plant based diet.