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

Where does our food come from? Earth as an Apple http://www.farmland.org/Flash/appleEarth.html 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

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

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

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

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.

HOW TO FEED THE WORLD http://www.youtube.com/watch?v=QloMOOG-bbE

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

Agriculture

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

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

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

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

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

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

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

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

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

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

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

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