With the help of robots, scientists are trying to find traces of water on Mars and the same thing could happen in the near future on the moons of Jupiter and Saturn. In short, water is essential for life as we know it.
On Planet Earth water is abundant but not unlimited. The total quantity of water on the Earth’s surface, in the atmosphere and below ground, is practically the same as it was at the time of the dinosaurs, but fresh water makes up just 2.5% of the total and much of it is trapped in the form of ice in the Antarctic.
The water actually available to us to meet the needs of 7 billion people makes up just 0.007% of what is present on the planet: it is therefore a precious and fragile resource that must be protected and used responsibly. That is why it is so important to talk about the water footprint.
What is the water footprint and what areas does it concern?
The term “water footprint” was coined in 2002 by the Dutch academic Arjen Hoekstra, along the lines of the other parameters: the environmental and carbon footprints. These are all indicators that measure the individual and collective impact on the environment: from the more general environmental footprint to the more specific water and carbon footprints, which, respectively, measure water consumption and carbon dioxide emissions
In actual fact this concept was not new. In 1993 British geographer John Anthony Allan had come up with the concept of “virtual water” to refer to the “hidden” or non-visible water used to produce food products and other commodities.
Building on Allan’s theory, Hoekstra formulated the concept of the water footprint to include both direct consumption, i.e., water consumed by a person, company or country, and indirect consumption that includes the sum of the water footprint of all products consumed.
Technically, the water footprint can be divided into three components:
- green water derived from atmospheric precipitation, including the water that remains for some time on the ground.
- blue water originating from surface water like lakes, rivers and underground springs.
- gray water concerns the pollution of water, and more precisely corresponds to the quantity of freshwater necessary to assimilate the polluting substances that result from human activities.
In 2008 Hoekstra founded the Water Footprint Network, an international platform that brought together companies, associations and individual citizens in order to raise awareness among the population about the water footprint and to help optimize consumption around the world.
Today the issue has become much more pressing due to a number of factors: the rapid growth of global population with the consequent increase in water consumption, climate change, which has caused an increase in anomalies such as droughts, and pollution, which reduces the quantity of clean water available to us.
Overall, the water footprint, just like its carbon equivalent, is a good indicator with which to evaluate the sustainability of production processes in our society but also our own personal behaviors. In order to assess environmental sustainability, we need to be able to measure it.
People’s water footprint
A person’s water footprint is composed only in a small part of the water consumed directly for drinking, cooking and washing. Most of it originates from the water used in the production, transport and distribution of the products we buy and consume, from food to clothes, mobility to energy consumption, products for the home to personal hygiene items.
The Water Footprint Network has estimated that the water footprint of an individual in our globalized economy can vary between 1,500 and 10,000 liters a day. This figure may seem surprisingly high at first glance and it is precisely for this reason that it should be kept in mind so we can be fully aware of our impact on the environment.
Naturally, a person’s water footprint depends on a number of different variables, including where that individual lives and their lifestyle, including their diet. In particular, consumption of red meat has a notably high impact: a 200-gram beef steak, for example, requires four times as much water as the same quantity of chicken, an amount of water equal to 47 eight-minute showers. These figures are based on the sum of water used in all phases: from the cultivation of the feed necessary to rear the livestock to the transport of the meat product to the consumer’s table.
With this in mind, the Water Footprint Network has developed an online calculator with which it is possible for anyone to work out their own water footprint based on parameters such as country of residence and meat consumption. The tool gives approximate results based on averages for people with the same characteristics. For more personalized results, it’s possible to use another online calculator, which is more precise and considers direct water consumption and dietary habits in greater detail.
In all of these calculations, however, country of residence is a key parameter. For example, a person with an annual income of 20,000 dollars and a moderate consumption uses 1,750.9 cubic meters each year if he or she lives in Austria, 2,992.2 in Mexico and 3,139.9 in Saudi Arabia, while this figure falls to 114.4 cubic meters in Burundi.
The water footprint of companies
For companies the water footprint is a more complex parameter: it measures all of the water used to produce the set of goods or services that it supplies, plus the water used along the entire supply chain and that linked to the actual use of the products.
The food industry makes particularly heavy use of water, both in terms of crops and livestock. The Water Footprint Network provides a list with the figures relating to the water footprint for various types of food, specifying the water footprint in terms of green, blue and gray water for each one. Naturally, these are approximate figures. The water footprint particularly depends on place of production and other parameters.