6 age and human health (good)

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
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2. 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
Earth as an Apple http://www.farmland.org/Flash/appleEarth.html
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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
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4. Nutrition
•Undernourishment =
•too few calories
•(especially developing world)
•Overnutrition =
•too many calories
•(especially developed world)
•Malnutrition = lack of nutritional requirements
Figure 9.2
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5. Percentage of population affected by undernutrition by country, according to United Nations statistics
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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.
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7. HOW TO FEED THE WORLD
•http://www.youtube.com/watch?v=QloMOOG- bbE
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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
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9. Agriculture
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10. 2,000
1,500
1,000
500
0
Grain production (millions of tons)
1950
1960
1970
1980
1990
2000
2010
Total World Grain Production
Year
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11. 400
350
300
250
150
Per capita grain production (kilograms per person)
1950
1960
1970
1980
1990
2000
2010
World Grain Production per Capita
200
Year
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12. Calories per day per person
3,700
3,500
3,300
3,100
2,900
2,700
2,500
2,300
2,100
1960
1970
1980
1990
2000
2010
2030
Year
Developed countries
World
Developing countries
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13. Figure 14-3 Page 276
Croplands
• 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
Ecological Services
Economic Services
• Food crops • Fiber crops • Crop genetic resources • Jobs
Natural Capital
Croplands
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
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14. Biodiversity Loss
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
Soil
Erosion Loss of fertility Salinization Waterlogging Desertification
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15. Air Pollution
Greenhouse gas emissions from fossil Fuel issue Other air pollutants from fossil fuel use Pollution from pesticide sprays
Water
Water waste Aquifer depletion Increased runoff and flooding from land cleared to grow crops Sediment pollution from erosion Fish kills from pesticide runoff
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
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16. 4%
2%
6%
5%
17% of total commercial energy use
Crops
Livestock
Food processing
Food distribution and preparation
Food production
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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
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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
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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
•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
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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
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21. To feed the world….
•Conservation of matter
–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
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