1. Food The major limiting factor to human population growth
Depends on environment and socio-political issues
Right now distribution is the main problem
If the human population continues to grow, quantity will be the problem

2. Where does our food come from?
Earth as an Apple
Where does our food come from?
Land crops and livestock!
Only 14 species of plants
Cash crops
Subsistence crops
Top food crops:
Wheat, rice, maize, potatoes

3. How much food do people need?
2600 calories/day
If they don’t get this: undernourishment
If they don’t get specific nutrients: malnourishment
Marasmus, kwashiorkor, chronic hunger
On the flip side of the coin: obesity

4. Nutrition Undernourishment = too few calories
(especially developing world)
Overnutrition =
too many calories
(especially developed world)
Malnutrition = lack of nutritional requirements
(causes numerous diseases, esp. in developing world)
Figure 9.2

5. Percentage of population affected by undernutrition by country, according to United Nations statistics

6. Global food security
The world still has 800 million hungry people, largely due to inadequate distribution.
Global food security is a goal of scientists and policymakers worldwide.

7. HOW TO FEED THE WORLD

8. The best ways
“Give a man a fish and you feed him for a day. Teach a man to fish and you feed him for a lifetime.” –Lao Tzu
Create systems where food is grown and distributed locally

9. Agriculture

10. Total World Grain Production
2,000
1,500
Grain production
(millions of tons)
1,000
500
1950
1960
1970
1980
1990
2000
2010
Year
Total World Grain Production

11. Per capita grain production (kilograms per person)
400
350
Per capita grain production
(kilograms per person)
300
250
200
150
1950
1960
1970
1980
1990
2000
2010
Year
World Grain Production per Capita

12. Calories per day per person
3,700
3,500
Developed countries
3,300
3,100
Calories per day per person
2,900
World
2,700
2,500
Developing
countries
2,300
2,100
1960
1970
1980
1990
2000
2010
2030
Year

13. Figure 14-3 Page 276 Natural Capital Croplands Ecological Services
Economic
Services
Ecological Services
Economic Services
Help maintain water flow and
soil infiltration
Provide partial erosion protection
Can build soil organic matter
Store atmospheric carbon
Provide wildlife habitat for some
species
Food crops
Fiber crops
Crop genetic
resources
Jobs
• Help maintain water
flow and soil infiltration
• Provide partial erosion
protection
• Can build soil organic
matter
• Store atmospheric
carbon
• Provide wildlife habitat
for some species
• Food crops
• Fiber crops
• Crop genetic
resources
• Jobs

14. Biodiversity Loss Soil
Loss and degradation of habitat from
clearing grasslands and forests and
draining wetland
Fish kills from pesticide runoff
Killing of wild predators to protect
livestock
Loss of genetic diversity from
replacing thousands of wild crop
strains with a few monoculture strains
Erosion
Loss of fertility
Salinization
Waterlogging
Desertification

15. Air Pollution Water Greenhouse gas emissions from fossil Fuel issue
Water waste
Aquifer depletion
Increased runoff and
flooding from land cleared
to grow crops
Sediment pollution from
erosion
Fish kills from pesticide
runoff
Greenhouse gas emissions from fossil
Fuel issue
Other air pollutants from fossil fuel use
Pollution from pesticide sprays
Surface and groundwater
pollution from pesticides
and fertilizers
Overfertilization of lakes
and slow-moving rivers
from runoff of nitrates
and phosphates from
fertilizers, livestock
wastes, and food
processing wastes

16. Food distribution and preparation
17% of total
commercial
energy use 4% 2% 6% 5%
Crops
Livestock
Food processing
Food distribution and preparation
Food production

17. Producing and eating meat
Land use issues
More land needed
More land needed for grazing than grain production
Acre of grain for human consumption feeds more than an acre used for grazing
Land needed to grow forage AND raise animals: Housing, food storage and waste disposal

18. Producing and eating meat
Energy issues
Eating at a lower trophic level
More solar energy available to humans, less lost through trophic transfer
Storage of grain less energetically expensive than processing and storing meat
Transport, slaughter and refrigeration
Energy costs associated with meat production
Producing grain for livestock
Fertilizers, irrigation, pesticides, farm machinery
Animal waste management
Pumping, treatment, transport, disposal
Animal care and round up of free range livestock

19. Eating less meat: Pro and Con
Advantages
Reduced risk of disease
Cholesterol
Clogged arteries
Hypertension
Heart disease
Reduced chemical exposure
Hormones
Steroids
Antibiotics
Pesticides (Biomag!)
Reduced exposure to disease
Mad Cow
Salmonella/ E. coli
Parasites
Disadvantages
Meat an excellent source of protein
Essential amino acids
Rice and Beans!
Difficult to get enough protein without meat
Nutritional deficiencies
Kwashikor: Protein
Blindness: Vit. A
Pollegra: Vit. B
Anemia: Iron
Inadequate essential fats balance

20. How do we address world hunger?
Policy and behavioral changes
Eat lower on the food chain?
Modify food distribution
Improve infrastructure
Economic policies
End subsidies

21. To feed the world…. Conservation of matter Conservation of Energy
Available resources limit agricultural production
Nutrients used by plants
Nitrates: Protein and DNA
Phosphates: DNA, RNA, ATP
Soil degraded as nutrients removed by harvest
Conservation of Energy
Trophic level energy loss
Vegetarian vs Carnivorous diets
Green revolution
Increase yield per acre
Monoculture
Intensive tillage = soil erosion
Requires
Energy: Emissions and oil
Fertilizers and pesticides: Toxic pollution, soil salinization
Irrigation: Water rights and usage