12.3

What environmental problems arise from

food production?

Producing Food Has Major Environmental Impacts

Harmful effects of agriculture onBiodiversitySoilWaterAirHuman health

•Worse than any human activity

•¾ of water quality problems

Topsoil Erosion

Soil erosion Natural causes – flowing water, wind,

glaciersHuman causes – farming, mining,

deforestation, overgrazing, off-road vehicles

Two major harmful effects of soil erosion

Loss of soil fertilityWater pollution

Natural Capital Degradation: Global Soil Erosion

Drought and Human Activities Are Degrading Drylands

Desertification – mostly in Africa and AsiaModerate (10-25% drop in productivity)Severe (25-50% drop in productivity)Very severe (more than 50% drop)http://www.youtube.com/watch?feature=endscreen&NR=1&v=FKEKhdt7Mks

Effect of global warming on desertification- expected to increase severe/ prolonged drought.

Results -drop infood production, water shortagesand refugees

Desertification of Arid and Semiarid Lands

Excessive Irrigation ProblemsMost 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, EgyptWaterlogging – accumulation of water

underground which raises the water tableFarmers 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

Limits to Expanding the Green RevolutionsDepletion of water suppliesWasteful use of irrigation waterSoil salinizationClimate 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

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.

Controversy over Genetically Engineered FoodsProsCons

What about chimeraplasty?Inserting a Chemical InstructionThat attaches toA gene to get desired traits.No mixing genes Of different species

Food and Biofuel Production Systems Have Caused Major

Biodiversity LossesBiodiversity threatened when

Forest and grasslands are replaced with croplands

Agrobiodiversity threatened whenHuman-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

Industrialized Meat Production Has Harmful Environmental

Consequences

Producing Fish through Aquaculture

Can Harm Aquatic Ecosystems

What environmental problems arise from food production?1.Topsoil erosion2.Drought and human activities degrade

drylands3.Excessive irrigation4.Limits to the Green Revolution5.Industrialized food production requires huge

inputs of energy6.Controversy over genetically engineered foods7.Food and biofuel production systems affect

biodiversity8.Industrialized meat production are energy

intensive9.Aquaculture can harm aquatic ecosystems

12.4

How can we protect crops from pests more

sustainably?

Nature Controls the Populations of Pests

What is a pest?

Natural enemies—predators, parasites, disease organisms—control pestsIn 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

PesticidesPesticides

InsecticidesHerbicidesFungicidesRodenticides (rats and mice)

Herbivores overcome plant defenses through natural selection: coevolution

First-generation pesticides – natural chemicals from plants

Second-generation pesticidesPaul Muller: DDTBenefits versus harm

Broad-spectrum agents- DDT, malathion and parathion

Persistence – length of time they remain deadly in the environment

DDTdichlorodiphenyltrichloroethane 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.

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

Rachel CarsonBiologist

Silent Spring - 1962

Potential threats of uncontrolled use of pesticidesDDT pp. 87-91 and dieldrin 91-94

Advantages of Modern Synthetic Advantages of Modern Synthetic PesticidesPesticidesSave 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

Synthetic Pesticides Have DisadvantagesAccelerate 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

Chemical groups of PesticidesNatural organic pesticides come from plants

tobacco produces toxic nicotine sulfate-toxic to insects and mammalspyrethrum- 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.

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 injuredUnion 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

However…Pesticide use has not reduced U.S. crop loss to

pests3 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 susceptibleFor their body size, they eat more food, drink more water and breathe more air

THE UNPREDICTABILITY OF INSECTICIDES

THE CATS OF BORNEO

Malaria and dieldrin (relative to DDT)Kill the mosquitos to prevent malaria!

Laws and Treaties Can Help to Protect Us from the Harmful Effects of Pesticides

Over 25,000 different commercial pesticidesU.S. federal agencies regulate sale/use

EPAUSDAFDAFederal Insecticide, Fungicide, and Rodenticide Act

(FIFRA) first passed in 1947 and amended in 1972Food Quality Protection Act 1996- 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

Laws Controlling Pesticide UseFood, 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)

Alternatives to Using PesticidesFool 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 perfumesE.g., pheromones (sex attractants)

Bring in hormones – use to disrupt developmental processes

Scald them with hot water – works on cotton, alfalfa

Integrated Pest Management

Integrated pest management (IPM) Coordinate: cultivation, biological

controls, and chemical tools to reduce crop damage to an economically tolerable level

DisadvantagesTakes knowledge of the specific pestTakes timeMethods may vary from place to placeInitial costs highGovernment subsidies for using chemicals

Systems Approach- Integrated Pest Management (IPM)IPM

Combination of pest control methods that keeps pest population low without economic loss

Conventional pesticides are used sparingly when other methods fail

IPM Project

12.4 HOW DO WE PROTECT CROPS FROM PESTS?

1.Nature controls most pest populations

2.Use pesticides3.Laws and treaties4.Biological, ecological and other

alternatives to pesticides5.Integrated pest management

12.5

How can we improve food security?

Food Production and SecurityControl prices – government can set limits on food

pricesProvide subsidies – government can provide subsidiesLet the marketplace decide

United Nations Children’s Fund (UNICEF) suggests these measures to save children from effects of povertyImmunizing children against childhood diseasesEncourage breast-feeding Prevent dehydration in infants and children – mix

sugar/salt in their waterPrevent blindness by giving children a vitamin A capsule

2x/yrProvide family planning servicesIncrease education for womenPREVENTING HEALTH PROBLEMS IN CHILDREN CAN

INCREASE FOOD SECURITY

12.6

HOW CAN WE PRODUCE FOOD MORE

SUSTAINABLY?

Soil Conservation Methods- Reduce soil erosion

Eliminate or minimize plowing/tillingConservation 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

Case in Point: American Dust Bowl

Great Plains have low precipitation and subject to drought and wind1930-1937 severe droughtfarmers 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.

http://www.youtube.com/watch?v=x2CiDaUYr90

Restore Soil FertilityOrganic 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

Reduce Soil Salinization and Desertification

Soil salinizationPrevention – reduce irrigation/plant salt tolerant

cropsClean-up – stop growing/ flush soil/underground

drainage systems

Desertification, reducePopulation growthOvergrazingDeforestationDestructive forms of planting, irrigation, and mining

Practice More Sustainable AquacultureOpen-ocean aquaculture

Farm inland in zero discharge ponds/tanksSalmon, 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.

Produce Meat More Efficiently and Humanely

Shift to more grain-efficient forms of proteinpoultry 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

Whole foods 5-step animal rating

MOVE DOWN THE FOOD CHAIN AND SLOW POPULATION GROWTHMEAT PRODUCTION/DELIVERY CAUSES 40% MORE

GHG THAN ALL THE WORLD’S MODES OF TRANSPORTATION.

DECREASING THE AMOUNT OF MEAT AND SWITCHING TO MORE ENERGY EFFICIENT CHICKEN AND HERBIVOROUS FISH IS ALSO MORE HEALTHY AND INCREASES LIFE EXPECTANCY.

MEDITERRANEAN-TYPE DIETS INCLUDE LESS MEAT/CHEESE/SEAFOOD

VEGETARIAN DIETS

SLOWING THE POPULATION GROWTH REDUCES HARMFUL EFFECTS OF AGRICULTURE.

What is Organic Farming?

Farming with little or no synthetic fertilizers/pesticides/ or GE seeds

Fig. 12-31, p. 307

SOLUTIONS

Sustainable Organic Agriculture

More LessHigh-yield polyculture

Soil erosion

Organic fertilizers

Aquifer depletion

Biological pest control

Overgrazing

OverfishingIntegrated pest management

Loss of biodiversity

Efficient irrigation

Perennial crops Subsidies for unsustainable farming and fishing

Food waste

Crop rotationWater-efficient crops

Soil salinizationSoil conservationSubsidies for sustainable farming and fishing

Population growth

Poverty

Buy Locally Grown Food- be a locovore!Supports local economies

Reduces environmental impact on food production

Community-supported agriculture (CSA)

Farmers’ markets

Sun Coffee vs Shade CoffeeCoffee Grown in the sunlight

Coffee Grown under the shade of trees

Planted in higher densityNeeds more fertilizers and pesticidesSo much coffee was produced that the demand decreased and prices decreasedIncreased erosion and toxic runoffSoil lacks nutrients

Lower yield No need for fertilizers and pesticides because the birds and insects take care of disease and hungry insectsGreater biodiversitySoil is healthy and can produce coffee yearly

Modern industrial agriculture violates the 4 basic principles of sustainability

Too many fossil fuelsToo little recyclingAccelerates soil erosionDoes little to preserve

agrobiodiversity and can destroy/degrade wildlife habitats

HOW CAN WE PRODUCE FOOD MORE SUSTAINABLY?1.Reduce soil erosion2.Restore soil fertility3.Reduce soil salinization and desertification4.Practice more sustainable aquaculture5.Produce mean more efficiently and humanely6.Move down the food chain and slow population

growth7.Shift to more sustainable agriculture8.Buy locally grown food

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

Is modern agriculture really the best way to feed a population?

Read the article and answer the questions.

Elements

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