Calculating water footprints of animal, plant proteins

Jan 31, 2011

Many times more water is needed for the production of meat and other animal products, such as eggs and dairy produce, than for the production of plant products. The University of Twente (The Netherlands) has for the first time calculated the exact water footprint of both animal and plant products per kilo, per calorie and per protein. Among the results of the calculations are that beef uses up twenty times more water per calorie than grain or potatoes. In combination with the growing world population, this is putting pressure on the earth's freshwater resources: only three percent of all the water on earth is fresh, and only a small proportion of this is available for human use.

The Twente Water Centre, the University of Twente's centre of expertise in the area of and governance, has developed a specialism in the calculation of the water footprint of products and production methods. Many companies make use of this expertise, out of cost considerations and because they are increasingly confronted with water shortages. For the first time, it has now been calculated how much fresh water is needed for the production of all common protein products. For a kilo of beef, for example, 15,000 litres are needed. Pork uses up 6,000 litres of water per kilo and chicken 4,300 litres. 4,000 litres of water are needed for a kilo of pulses, while a kilo of soya beans uses up 'just' 2,100 litres. Per gram of protein, meat has a water footprint that is 1.5 to 6 times larger than that for pulses. There are also great differences between animal and plant products when the per calorie is calculated. Beef, for example, scores on average twenty times higher than grain or potatoes.

The key distinguishing factor between the various types of meat is the type and amount of feed that is needed to allow the animal to grow. For example, a cow has to eat much more to put on a kilo of flesh than a chicken or a pig does. According to Arjen Hoekstra, professor of Water Engineering & Management at the University of Twente, "what is known as feed conversion efficiency partly determines the water footprint. After all, all animal feed is produced with the use of water. Irrigation is therefore needed in large parts of the world because there is too little rainfall in general or in particular periods."

The location where the livestock is raised also determines the water footprint. Livestock that grazes outdoors uses up rainwater that is naturally present in grass, while livestock in industrialized animal production is given more feed, which originates from fields that sometimes have to be irrigated. The researchers from the University of Twente have therefore also taken into account the type of feed and its origin, which is sometimes in areas with a water shortage. The water demands of livestock breeding in the western world can therefore contribute to water shortages elsewhere. For example, a number of rivers in China are drying up before they reach the sea, partly because of the irrigation of agricultural land where animal feed is grown.

Johan van de Gronden, director of the WWF in the Netherlands, says: "The figures say a lot about the often hidden consequences of our everyday consumption pattern for the natural world. We already knew that a low-meat diet is not only healthier, but also better for nature and the climate. Now we can also see that unbridled meat consumption contributes to in other parts of the world. We don't need to become vegetarians en masse to give nature a helping hand. Just one meat-free day per week already makes a world of difference."

Explore further: Food shortages could be most critical world issue by mid-century

More information: The report The green, blue and grey water footprint of farm animals and animal products can be downloaded from: www.waterfootprint.org/Reports/Report-48-WaterFootprint-AnimalProducts-Vol1.pdf .

add to favorites email to friend print save as pdf

Related Stories

Pork belly cuts better for environment than beef steak

Mar 18, 2010

Milk, eggs, pork and chicken are friendlier for the environment than beef. This is the conclusion after examining sixteen life cycle assessment (LCA) studies of animal products. However, the margins for the various measurements ...

Greenhouse surprise for red meat

Feb 03, 2010

(PhysOrg.com) -- Beef produced in feedlots has a smaller carbon footprint than meat raised exclusively on pastures, according to the surprise results of a new study.

Mankind benefits from eating less meat

Apr 06, 2006

If people were to eat more vegetable proteins instead of animal proteins, this would result in multiple – and much-needed – benefits. Such a 'protein transition' will positively affect sustainable energy production, sustainable ...

Water: The forgotten crisis

Jul 10, 2008

This year, the world and, in particular, developing countries and the poor have been hit by both food and energy crises. As a consequence, prices for many staple foods have risen by up to 100%. When we examine the causes ...

Counting the cost of water

May 23, 2006

Economic expansion in China is threatening the country’s scarce water resources, according to a new study by the University of Leeds. Uneven development of trade across the country means that water-intensive ...

Recommended for you

More, bigger wildfires burning western US, study shows

13 hours ago

Wildfires across the western United States have been getting bigger and more frequent over the last 30 years – a trend that could continue as climate change causes temperatures to rise and drought to become ...

User comments : 0

More news stories

Six Nepalese dead, six missing in Everest avalanche

At least six Nepalese climbing guides have been killed and six others are missing after an avalanche struck Mount Everest early Friday in one of the deadliest accidents on the world's highest peak, officials ...

China says massive area of its soil polluted

A huge area of China's soil covering more than twice the size of Spain is estimated to be polluted, the government said Thursday, announcing findings of a survey previously kept secret.

There's something ancient in the icebox

Glaciers are commonly thought to work like a belt sander. As they move over the land they scrape off everything—vegetation, soil, and even the top layer of bedrock. So scientists were greatly surprised ...

Clean air: Fewer sources for self-cleaning

Up to now, HONO, also known as nitrous acid, was considered one of the most important sources of hydroxyl radicals (OH), which are regarded as the detergent of the atmosphere, allowing the air to clean itself. ...

Scientists tether lionfish to Cayman reefs

Research done by U.S. scientists in the Cayman Islands suggests that native predators can be trained to gobble up invasive lionfish that colonize regional reefs and voraciously prey on juvenile marine creatures.

Leeches help save woman's ear after pit bull mauling

(HealthDay)—A pit bull attack in July 2013 left a 19-year-old woman with her left ear ripped from her head, leaving an open wound. After preserving the ear, the surgical team started with a reconnection ...