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What environmental problems arise from food production?

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Presentation on theme: "What environmental problems arise from food production?"— Presentation transcript:

1 What environmental problems arise from food production?
12.3 What environmental problems arise from food production?

2 Producing Food Has Major Environmental Impacts
Harmful effects of agriculture on Biodiversity Soil Water Air Human health Worse than any human activity ¾ of water quality problems


4 Natural Capital Degradation: Global Soil Erosion
Topsoil Erosion Soil erosion Natural causes – flowing water, wind, glaciers Human causes – farming, mining, deforestation, overgrazing, off-road vehicles Two major harmful effects of soil erosion Loss of soil fertility Water pollution Natural Capital Degradation: Global Soil Erosion

5 Drought and Human Activities Are Degrading Drylands
Desertification – mostly in Africa and Asia Moderate (10-25% drop in productivity) Severe (25-50% drop in productivity) Very severe (more than 50% drop) Effect of global warming on desertification- expected to increase severe/ prolonged drought. Results -drop in food production, water shortages and refugees Desertification of Arid and Semiarid Lands

6 Excessive Irrigation Problems
Most irrigation water has many dissolved salts from rocks and soil Salinization – evaporation of water, leaving the salt behind. Stunts crop growth, lowers yields and kill plants/ruin land Worst in China, India, Egypt Waterlogging – accumulation of water underground which raises the water table Farmers often water often in order to leach the salts deeper into the soil, but if water table rises, the saline water can be reached by the plants’ roots

7 Limits to Expanding the Green Revolutions
Depletion of water supplies Wasteful use of irrigation water Soil salinization Climate change (melting mountain glaciers that provide summer waters) Farmers lack the money to irrigate improve efficiency of irrigation techniques GM crops that are more drought and cold tolerant and multicropping can increase yields

8 Industrialized Food Production Requires Huge Inputs of Energy
Industrialized food production and consumption have a large net energy loss Food travels a total of 1300 miles from farm to plate! Industrialized Agriculture uses ~17% of All Commercial Energy Used in the U.S.

9 Controversy over Genetically Engineered Foods
Pros Cons What about chimeraplasty? Inserting a Chemical Instruction That attaches to A gene to get desired traits. No mixing genes Of different species

10 Food and Biofuel Production Systems Have Caused Major Biodiversity Losses
Biodiversity threatened when Forest and grasslands are replaced with croplands Agrobiodiversity threatened when Human-engineered monocultures are used Importance of seed banks (97% of food plant varieties available in the 1940s no longer exist) Newest: underground vault in the Norwegian Arctic

11 Industrialized Meat Production Has Harmful Environmental Consequences

12 Producing Fish through Aquaculture Can Harm Aquatic Ecosystems

13 What environmental problems arise from food production?
Topsoil erosion Drought and human activities degrade drylands Excessive irrigation Limits to the Green Revolution Industrialized food production requires huge inputs of energy Controversy over genetically engineered foods Food and biofuel production systems affect biodiversity Industrialized meat production are energy intensive Aquaculture can harm aquatic ecosystems

14 How can we protect crops from pests more sustainably?
12.4 How can we protect crops from pests more sustainably?

15 Nature Controls the Populations of Pests
What is a pest? Natural enemies—predators, parasites, disease organisms—control pests In natural ecosystems In many polyculture agroecosystems there is a balance- spiders kill more insects every year than chemicals do! What will happen if we kill the pests? Spiders are Important Insect Predators

16 Pesticides Pesticides
Insecticides Herbicides Fungicides Rodenticides (rats and mice) Herbivores overcome plant defenses through natural selection: coevolution First-generation pesticides – natural chemicals from plants Second-generation pesticides Paul Muller: DDT Benefits versus harm Broad-spectrum agents- DDT, malathion and parathion Persistence – length of time they remain deadly in the environment

17 DDT dichlorodiphenyltrichloroethane a chlorinated hydrocarbon
Used during WW II to kill mosquitoes in order to prevent malaria and typhus. It is not water soluble so it accumulates in the tissues of organisms. Got in the waters, then fish, then birds. Caused bird eggs to be too thin so they broke when sat on Contributed to the declining numbers of bald eagles, bats, peregrine falcons Banned in 1972, but many countries still use it.

18 Why Are We Concerned About DDT
Why Are We Concerned About DDT? Even though DDT has been banned since 1972, it can take more than 15 years to break down in the environment. What harmful effects can DDT have on us? Damages the liver Temporarily damages the nervous system Can cause liver cancer Damages reproductive system How are we exposed to DDT? By eating contaminated fish and shellfish Infants may be exposed through breast milk By eating imported food directly exposed to DDT By eating crops grown in contaminated soil

19 Rachel Carson Biologist Silent Spring - 1962
Potential threats of uncontrolled use of pesticides DDT pp and dieldrin 91-94

20 Advantages of Modern Synthetic Pesticides
Save human lives Increases food supplies and profits for farmers Work quickly Health risks are very low relative to their benefits New pest control methods: safer and more effective

21 Synthetic Pesticides Have Disadvantages
Accelerate the development of genetic resistance to pesticides by pest organisms Expensive for farmers Some insecticides kill natural predators and parasites that help control the pest population Pollution in the environment Some harm wildlife Some are human health hazards


23 Chemical groups of Pesticides
Natural organic pesticides come from plants tobacco produces toxic nicotine sulfate-toxic to insects and mammals pyrethrum- comes from chrysanthemum and is used in animal dips and flea shampoo Chlorinated hydrocarbons- DDT, aldrin, dieldrin, chlordane- are nerve toxins that cause nausea, vomiting, convulsions and death. Linked to fertility disorders and may be carcinogens. Highly persistent, fat soluble and subject to biomagnification Organophosphates – malathion, parathion and tetrethylpyrophosphate. Used as nerve agents in WWII. Break down quickly. More toxic in lower amounts that chlorinated hydrocarbons because they are absorbed quickly. Cause headache, slow heart beat, confusion, paralysis, coma, death.

24 Carbamates – are insecticides, herbicides and fungicides
Carbamates – are insecticides, herbicides and fungicides. Lack persistence and bioaccumulation. Examples are carbaryl (Sevin) and aldicarb (Temik). Also act on the nervous system and have same effects. Case Study- Bhopal, India 1984 Poisonous gas leak that killed 10,000 – 30,000 and more than 500,000 were injured Union carbide was producing an insecticide- called Sevin The chemical name was methyl icocyanate (MIC) Once inhaled, MIC destroys the respiratory system with lightning speed, causes irreversible blindness and burns the pigment of the skin

25 However… Pesticide use has not reduced U.S. crop loss to pests
3 conclusions are: 1. Loss of crops today is greater than in the 1940s. 37% of crops lost now compared to 31% 2. High environmental, health, and social costs with use 3. Use alternative pest management practices Pesticide industry refutes these findings Children are most susceptible For their body size, they eat more food, drink more water and breathe more air


THE CATS OF BORNEO Malaria and dieldrin (relative to DDT) Kill the mosquitos to prevent malaria!

28 Laws and Treaties Can Help to Protect Us from the Harmful Effects of Pesticides
Over 25,000 different commercial pesticides U.S. federal agencies regulate sale/use EPA USDA FDA Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) first passed in 1947 and amended in 1972 Food Quality Protection Act EPA must reduce allowed levels of pesticide residues in food Effects of active and inactive pesticide ingredients are poorly documented Circle of poison, boomerang effect – residues of banned pesticides exported to countries can return to those countries on imported food. Wind also carries pesticides

29 Laws Controlling Pesticide Use
Food, Drug, and Cosmetics Act (1938) Pesticide Chemicals Amendment (1954) Delaney Clause (1958) (a zero cancer risk standard) Federal Insecticide, Fungicide, and Rodenticide Act (1947) federal control of pesticide distribution, sale, and use Food Quality Protection Act (1996)

30 Alternatives to Using Pesticides
Fool the pest – rotating crops, adjust planting times Provide homes for pest enemies Implant genetic resistance- GE used to speed up development of pest/disease-resistant crop strains Bring in natural enemies Use insect perfumes E.g., pheromones (sex attractants) Bring in hormones – use to disrupt developmental processes Scald them with hot water – works on cotton, alfalfa

31 Integrated Pest Management
Integrated pest management (IPM) Coordinate: cultivation, biological controls, and chemical tools to reduce crop damage to an economically tolerable level Disadvantages Takes knowledge of the specific pest Takes time Methods may vary from place to place Initial costs high Government subsidies for using chemicals

32 Systems Approach- Integrated Pest Management (IPM)
Combination of pest control methods that keeps pest population low without economic loss Conventional pesticides are used sparingly when other methods fail

33 IPM Project

Nature controls most pest populations Use pesticides Laws and treaties Biological, ecological and other alternatives to pesticides Integrated pest management

35 How can we improve food security?
12.5 How can we improve food security?

36 Food Production and Security
Control prices – government can set limits on food prices Provide subsidies – government can provide subsidies Let the marketplace decide United Nations Children’s Fund (UNICEF) suggests these measures to save children from effects of poverty Immunizing children against childhood diseases Encourage breast-feeding Prevent dehydration in infants and children – mix sugar/salt in their water Prevent blindness by giving children a vitamin A capsule 2x/yr Provide family planning services Increase education for women PREVENTING HEALTH PROBLEMS IN CHILDREN CAN INCREASE FOOD SECURITY


38 Soil Conservation Methods- Reduce soil erosion

39 Eliminate or minimize plowing/tilling
Conservation tillage farming- uses no machinery- leaves the crop residue on the surface to decompose – a special machine drills seeds directly through the crop residues This methods helps store carbon and keep other nutrients in the soil –uses less fertilizers/ lowers use of water/fertilizer runoff and tractor fuel But cannot be used for all crops, costly machinery, and increase use of herbicides

40 Case in Point: American Dust Bowl
Great Plains have low precipitation and subject to drought and wind severe drought farmers had plowed land deeply and did not rotate crops, leave them fallow or plant cover crops to prevent erosion- No natural vegetation roots to hold soil in place- Winds blew soil as far east as NYC and DC. Farmers went bankrupt- many moved to Ca and became migrant workers.

41 Restore Soil Fertility
Organic fertilizer - animal manure, green manure (freshly cut or growing green vegetation), compost (microorganisms break down organic matter like leaves, crop residues) Crop rotation to preserve nutrients – corn and cotton deplete nitrogen and legumes add nitrogen Manufactured inorganic fertilizers- contain compounds that add nitrogen, phosphorus and potassium – do not add organic material to the soil – need to be controlled carefully since fertilizers can run off the land and pollute the waters

42 Reduce Soil Salinization and Desertification
Prevention – reduce irrigation/plant salt tolerant crops Clean-up – stop growing/ flush soil/underground drainage systems Desertification, reduce Population growth Overgrazing Deforestation Destructive forms of planting, irrigation, and mining


44 Practice More Sustainable Aquaculture
Open-ocean aquaculture Farm inland in zero discharge ponds/tanks Salmon, tuna and cod are carnivores. Carp, tilapia and catfish are herbivores – more sustainable Polyculture – raising fish/shrimp/algae/seaweed/shellfish together and the wastes of one is food for another. Shrimp and tilapia can be grown together for they feed at different levels.

45 Produce Meat More Efficiently and Humanely
Shift to more grain-efficient forms of protein poultry and plant eating farmed fish Develop meat substitutes; eat less meat Whole Food Markets: more humane treatment of animals 38% of world’s grain harvest and 37% of world’s fish catch are used to produce animal protein

46 Whole foods 5-step animal rating


48 What is Organic Farming?
Farming with little or no synthetic fertilizers/pesticides/ or GE seeds

49 SOLUTIONS Sustainable Organic Agriculture More Less
High-yield polyculture Soil erosion Aquifer depletion Organic fertilizers Overgrazing Biological pest control Overfishing Integrated pest management Loss of biodiversity Efficient irrigation Food waste Subsidies for unsustainable farming and fishing Perennial crops Figure 12.31 Major components of more sustainable, low-throughput agriculture based mostly on mimicking and working with nature (Concept 12-6B). Question: Which two solutions do you think are the most important? Why? Crop rotation Water-efficient crops Soil salinization Soil conservation Population growth Subsidies for sustainable farming and fishing Poverty Fig , p. 307

50 Buy Locally Grown Food- be a locovore!
Supports local economies Reduces environmental impact on food production Community-supported agriculture (CSA) Farmers’ markets

51 Sun Coffee vs Shade Coffee
Coffee Grown in the sunlight Coffee Grown under the shade of trees Planted in higher density Needs more fertilizers and pesticides So much coffee was produced that the demand decreased and prices decreased Increased erosion and toxic runoff Soil lacks nutrients Lower yield No need for fertilizers and pesticides because the birds and insects take care of disease and hungry insects Greater biodiversity Soil is healthy and can produce coffee yearly

52 Modern industrial agriculture violates the 4 basic principles of sustainability
Too many fossil fuels Too little recycling Accelerates soil erosion Does little to preserve agrobiodiversity and can destroy/degrade wildlife habitats

Reduce soil erosion Restore soil fertility Reduce soil salinization and desertification Practice more sustainable aquaculture Produce mean more efficiently and humanely Move down the food chain and slow population growth Shift to more sustainable agriculture Buy locally grown food

54 Albert Einstein “Nothing will benefit human health and increase chances of survival of life on earth as much as the evolution of a vegetarian diet.” What do you think about this quote, and would you be willing to eat less meat? Other vegetarians… Leonardo Da Vinci, Gandhi, Pythagoras, Mark Twain

55 Is modern agriculture really the best way to feed a population
Is modern agriculture really the best way to feed a population? Read the article and answer the questions.

56 Elements

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