The link between our food and our water footprint

Published 23/08/2012

World Water Week¹ kicks off on 26th August with a theme of water and its relationship to food security. It’s perfect Compassion material, so we thought we’d look at the relationship between food and water in a bit more detail.

Water, water everywhere…

We call it the "blue planet" for a reason – over two thirds of the Earth are covered in water, most of which is found in our vast oceans (97% to be precise). Although only a small percentage of water is fresh, it is as vital as oxygen, keeping us hydrated and allowing us to grow food.

And yet our blue planet is under strain, with many aquatic environments showing tell-tale signs of over-use and exploitation.

A jack of all trades

We don’t just drink the stuff – water is also a vital component for producing all manner of things, from iPads to jeans to (you guessed it!) food.

You’ve heard of a carbon footprint, right? Well, we all have a water footprint (WFP) too, and the food that we choose to eat, meat in particular, can have a dramatic effect on its size. But before we delve into the data, it’s important to understand the different types of water that make up our WFP.

What makes up your water footprint?

There are three types of water that make up your WFP (summarised in the diagram below):

Green water – this is the volume of rainwater used to produce something.
Blue water – this is the volume of surface and ground water (irrigation water) used to produce something.
Grey water – this is the volume of fresh water required to dilute any pollutants so that the quality of the polluted water remains above agreed water-quality standards.

So what’s the big deal with water and meat?

A recent Compassion in World Farming report² (written by global expert Professor Arjen Hoekstra) focused on water use in livestock farming. Looking at beef, chicken and pork, and focusing on several different regions – Brazil, China, the Netherlands, the USA and a global average – the report highlighted the fact that approximately 25% of global freshwater use is related to producing our meat and dairy; that’s a huge amount. And the majority of this 25% comes from animal-feed production – growing crops can be a thirsty business.

Green water dominates the water footprint of livestock farming, but this is of less concern than blue or grey water (given that green water is falling on the ground as rain anyway). As a result, the study focused on the blue and grey water. Here are the key findings:

Grass-fed animals are more water efficient – grain-based animal feeds use 43 times more blue water and 61 times more grey water per kg of feed than is needed for roughage-based animal feeds.
The global average WFP for beef is slightly higher in factory-farming systems compared to grazing systems.
The global average WFP for chicken is higher in grazing systems compared to factory-farming systems.

Making sense of these findings

It’s not surprising that some grazing/free-range farming systems can use a little bit more water. Pigs and chickens eat mainly grain regardless of the system that they are reared in. Furthermore, free-range animals tend to live longer and move more, and therefore tend to eat more food, which can increase the WFP.

This doesn’t mean that factory farming meat is the ethical choice! It’s often said that in a resource-constrained world, we need to strive for efficiency through the intensification of livestock farming. But this research shows that the theory doesn’t hold water. And it’s counter-productive in any case; you have to look at the bigger picture. Water is just one of many impacts of factory farming. With broiler chickens, for example, a factory-farmed bird will endure a horrific life and provide fattier, less nutritious meat, too.

The research also highlights the importance of location when it comes to farming. For example, it may be more effective for water management to accept a higher water footprint that is predominantly green (rain) water than a lower water footprint that is primarily blue (irrigation) and grey water.

And the fact that meat and dairy (regardless of its provenance) is fairly water intensive is exactly why our dietary mantra is eat better, eat less. Some of us at Compassion in World Farming like our meat as much as the next person, but we still see huge advantages in eating smaller amounts of higher-quality meat, including the reduction of our WFP for some animals. It’s about finding a balance.