The water behind the world’s meat
Producing the world’s meat, milk and eggs takes a staggering amount of water: around 2,422 billion cubic metres a year, according to the most complete global study of the question. That is about 77,000 cubic metres every second, enough to fill 30 Olympic swimming pools, and it makes up 29% of all the water used in farming1.
Almost none of it is water the animals drink. 98% of the total goes into growing their feed, the grass they graze and the maize, soy and other crops they eat. Most of it is rain that falls on fields and pasture, but about 12% of all the irrigation water in the world, pumped from rivers and underground, is used to grow animal feed rather than food for people1.
That study averaged the years 1996 to 2005, and no one has repeated it on the same global scale. Since then, world meat production has grown by about 60%6, so today’s real figure is very likely higher than the one shown here.
A kilogram of beef takes 15,400 litres of water
The reason meat is so thirsty is simple: animals turn only a small part of what they eat into meat, so every kilogram of meat carries the water needed to grow many kilograms of feed1.
Beef is by far the thirstiest. On a global average, a kilogram of beef takes about 15,400 litres of water to produce. Sheep meat takes about 10,400 litres, pork 6,000, goat meat 5,500 and chicken 4,300. Measured per calorie, beef uses 20 times as much water as cereals and starchy foods like potatoes1. Beef cattle alone account for a third of all the water used in animal farming.
That's how much water it takes, on average, to produce one kilogram of beef
Three quarters of farmland for 18% of our calories
Water is only one part of the bill. Half of all the world’s habitable land is used for farming, and about three quarters of that farmland is used for livestock, either as pasture or to grow feed. In return, livestock provides just 18% of the calories people eat and 37% of their protein2.
The scale of animal farming shows up in a startling way when you weigh the animals themselves. Livestock now make up 94% of the mass of all mammals on Earth, excluding humans, and farmed poultry make up 71% of the mass of all birds2. Wild animals are a small remainder.
Much of the land for new pasture has come from forests. Between 2005 and 2013, clearing land for cattle pasture was responsible for 41% of all tropical deforestation5.
The meat all this water and land produces, in tonnes.
Livestock and the climate
The Food and Agriculture Organization of the United Nations (FAO) estimates that livestock farming causes around 6.2 billion tonnes of greenhouse gases a year, about 12% of all the emissions caused by humans3. That figure includes everything from growing the feed to the animals’ own digestion.
Cattle are responsible for most of it: 3.8 billion tonnes, or 62% of the livestock total, counting both beef and dairy cattle. Slightly more than half of all livestock emissions are methane, a powerful greenhouse gas released as cattle, sheep and other ruminants digest grass3. That is why a kilogram of beef from a beef herd comes with around 99 kilograms of greenhouse gases, against about 10 for chicken4.
The animals behind most of livestock’s emissions.
Manure, fertiliser and dead zones
Meat also pollutes water. Farms spread fertiliser on the fields that grow animal feed, and livestock produce huge amounts of manure. When rain washes the excess nitrogen and phosphorus into rivers, lakes and coastal seas, it feeds blooms of algae. When the algae die and rot, they use up the oxygen in the water, leaving dead zones where fish cannot survive. This is called eutrophication, and agriculture causes 78% of it worldwide2.
The study behind the water counter measures this too, as grey water: the amount of clean water that would be needed to dilute the pollution to safe levels. It makes up 6.6% of animal farming’s water footprint, around 160 billion cubic metres a year1.
Where meat’s environmental footprint is heading
Meat production keeps growing, so its footprint is not about to shrink. But the mix of meat matters as much as the amount. The Organisation for Economic Co-operation and Development (OECD) and FAO expect livestock emissions to grow by about 6% to 2034, only half as fast as meat production, because more of the world’s meat is coming from chicken, which needs far less land, water and feed per kilogram than beef7.
That shift has a cost of its own, measured in the number of animals slaughtered, which is covered on the page for every land animal slaughtered for meat. And it does nothing for the forests already cleared. The biggest environmental gains would come from producing beef on less land and ending deforestation for pasture, which depends far more on governments and enforcement than on any single shopper’s choice. Meanwhile, the water behind the world’s meat, already higher than the number above, is almost certainly still rising.
The forests being cleared, much of it for cattle pasture.
The rest of what the world raises and eats is in the food section.
