Page 269 - Environment: The Science Behind the Stories

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Beef (245.0 m )
types of animals. Such energy efficiencies have ramifications
for land use because land and water are required to raise food
for the animals, and some animals require more than others.
Figure 10.10 shows the area of land and weight of water
required to produce 1 kg (2.2 lb) of edible protein for milk,
eggs, chicken, pork, and beef. Producing eggs and chicken
meat requires the least space and water, whereas producing
beef requires the most. Such differences show that when we
choose what to eat, we are also indirectly choosing how to
Pork Eggs Chicken Milk make use of resources such as land and water.
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2
2
2
(90.0 m ) (22.0 m ) (14.0 m ) (23.5 m )
(a) Land required to produce 1 kg of protein Rising demand led to feedlot agriculture
In traditional agriculture, livestock are kept by farming families
Beef (750 kg) near their homes or are grazed on open grasslands by nomadic
herders or sedentary ranchers. These traditions survive, but
the advent of industrial agriculture has brought a new method.
Feedlots, also known as factory farms or concentrated animal
feeding operations (CAFOs), are essentially huge warehouses
or pens designed to deliver energy-rich food to animals living
at extremely high densities (Figure 10.11). Today nearly half the
world’s pork and most of its poultry come from feedlots.
Feedlot operations allow for economic efficiency and
greater food production, and this makes meat affordable to more
people. At the same time, feedlot animals are generally fed grain
grown on cropland. One-third of the world’s cropland is devoted
Pork Eggs Chicken Milk to growing feed for animals, and 45% of our global grain pro-
(175 kg) (15 kg) (50 kg) (250 kg) duction goes to livestock and poultry. This elevates the price of
staple grains and endangers food security for the very poor.
(b) Water required to produce 1 kg of protein
For environmental quality, feedlots offer one very sig-
Figure 10.10 Producing different types of animal products nificant benefit: Taking cattle and other livestock off range-
requires different amounts of (a) land and (b) water. Raising cattle land and concentrating them in feedlots reduces the grazing
for beef requires by far the most land and water. Data from Smil, V., 2001. impacts they would otherwise exert across large areas of the
Feeding the world: A challenge for the twenty-first century. Cambridge, MA: MIT Press. landscape (pp. 247, 250). Animals that are densely concen-
In terms of protein, how many times more land does it take trated in feedlots will not contribute to overgrazing. However,
to produce beef than chicken? How many times more intensified animal production through the industrial feedlot
water does it take? model does exert other environmental impacts.

(a) Chicken factory farm in Arkansas (b) Cattle feedlot in Nebraska
Figure 10.11 Most meat eaten in the United States comes from animals raised in feedlots or factory
farms. These facilities house thousands of (a) chickens or (b) cattle at high densities. The animals are dosed
268 liberally with antibiotics to control disease.

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