1

Worldwide adoption of the American diet would require

“more grain than the world can grow and more energy, water, and land than the world can

supply”

D. Pimental and others, Science, 1980

2

Food, Hunger, and Nutrition

• Human Nutrition• World Food Resources• World Hunger • Agricultural Economics• Can we feed projected populations

sustainably?• Is it possible to convert to sustainable

agriculture in the US?

3

What should we eat?

• PROTEIN: need to maintain metabolic activity and cellular structure (1.3 oz/day)

• CARBOHYDRATES: energy to power the masses – starches, fruits, and vegetables

• FAT! lipids and oils: energy source. Need unsaturated lipids and essential fatty acids.

• MINERALS: build and regulate cells• VITAMINS: organic molecules necessary for life

Minimum daily intake should be 2500 calories (average)

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CS Fig. 9.6

5

Figure 09_07

CS Fig. 9.7

6

What do we eat?

• 30 crops feed the world• 3 crops provide over half of calories for the world

– Wheat, rice, corn• 2/3 of population eat primarily vegetarian diet• Protein sources: meat, fish, animal products (i.e.

dairy) Expensive!

• 1 billion in hunger; 1 billion overfed

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Nutrition

• The most common dietary problem in wealthy countries is over-nutrition.– In NA and Europe, average daily caloric intake is

3,500 calories.• Sub-Saharan Africa has not kept food production up to

pace of population growth.• Collapse of Soviet Union also led to significant collapse

in food production.

8

Figure 09_03

CS Fig. 9.3

9

Demographics of Hunger

CS Fig. 9.2

10

Is there enough for everyone?

Feeding the World:World Resources Institute

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Figure 09_05

CS Fig. 9.5

12

Where is it grown?

• US has 16% of world’s cropland and 255 million to feed

• China has 9% to feed 1.2 billion• India has 8% to feed 1 billion

• US grows almost half of the world’s maize– 90% is used to feed dairy and beef cattle

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Figure 09_11

CS Fig. 9.11

Number of kg of grain needed to produce 1 kg of bread or 1kg live weight gain

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Figure 09_12

CS Fig. 9.12 Concentrated feeding operation

1515

(~2.

5 ac

res)

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Worldwide adoption of the American diet would require “more grain than the world can grow and more energy, water, and land than the world can

supply”

or, put another way

If everyone ate like Americans do, the Earth could sustain 2.5 billion people

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Figure 09_09

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Agricultural Economics

• International food aid can stave off famine, but it can also create dependency and support repressive governments

• Cash crop problem– Developing country specializes in export crop– Economy becomes very sensitive to export price– Little of earnings reach underclass– Guatemala: 97% of citrus exported, population is

vitamin C deficient– Central America increased beef exports 6X in 60s-70s,

meat consumption per person decreased by half

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Are high inputs sustainable?

• No

• Remember, Sustainable agriculture works with nature. Diversification is key.

• Loading the soil with water and fertilizer, and expending lots of energy to do it is not exactly working with nature

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Is current agriculture sustainable?

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World Resource Institute Findings, 2000

• “Results show that, although food production has more than kept pace with population growth it has done so at the expense of biodiversity, clean water, carbon storage capacity and the quality of soils.

– Twenty to 30 percent of the world's forest areas have been converted to agriculture, resulting in extensive species and habitat loss.

– Soil degradation, including nutrient depletion, erosion, and salinization, is widespread. Salt accumulation in soils has damaged… 20 percent of the world's total irrigated land.

– Agriculture consumes 70 percent of the freshwater withdrawn annually by humans.

– Irrigation is draining more water than is being replenished by rainfall, causing water tables to fall.

– Moreover, many water sources are being polluted by excessive use of fertilizers and pesticides.

• For these trends to change, agricultural lands need to meet the double challenge of increasing food production while continuing to provide much-needed environmental goods and services.” WRI website

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America’s Quandary

• Agriculture is big business

• Big business is about the bottom line, not environmental sustainability

• If we shifted over to sustainable, small farms, there wouldn’t be enough food

– Note that animals play an important role in small farms. Everybody doesn’t have to become a vegetarian!

• Developing countries strive to be like America – is this a good thing?

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Sustainable farming in Minnesota?

• YES! Minnesota Institute for Sustainable Agriculture (MISA) keeps track of it

– http://www.misa.umn.edu/

– University of Minnesota, St. Paul

• By buying locally grown (usually organic) produce at your local coop or farmer’s market, you support sustainable farming

• The only way to make real change in a capitalist country is to vote with your wallet. What you buy will determine what is produced!

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The End.

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