LECTURE 4 - PART 1 : FOOD & SOIL

I. FOOD SECURITY & FOOD PRODUCTION :

- Many people suffer from chronic health and malnutrition• Food security means having daily access to enough nutritious food to live an active and healthy

life.• One of every six people in less-developed countries is not getting enough to eat, facing food

insecurity—living with chronic hunger and poor nutrition, which threatens their ability to lead healthy and productive lives. – The root cause of food insecurity is poverty.– Other obstacles to food security are political upheaval, war, corruption, and bad

weather, including prolonged drought, flooding, and heat waves.• To maintain good health and resist disease, individuals need fairly large amounts of

macronutrients, such as carbohydrates, proteins and fats, and smaller amounts of micronutrients—vitamins and minerals.

• People who cannot grow or buy enough food to meet their basic energy needs suffer from chronic undernutrition, or hunger.

• Many suffer from chronic malnutrition—a deficiency of protein and other key nutrients, which weakens them, makes them more vulnerable to disease, and hinders the normal development of children.

- Many people do not get enough vitamins and minerals• Deficiency of one or more vitamins and minerals, usually vitamin A, iron, and iodine.• Some 250,000–500,000 children younger than age 6 go blind each year from a lack of vitamin

A, and within a year, more than half of them die.• Lack of iron causes anemia which causes fatigue, makes infection more likely, and increases a

woman’s chances of dying from hemorrhage in childbirth. • 1/5 people in the world suffers from iron deficiency. • Chronic lack of iodine can cause stunted growth, mental retardation, and goiter. • Almost one-third of the world’s people do not get enough iodine in their food and water. • According to the FAO and the WHO, eliminating this serious health problem would cost the

equivalent of only 2–3 cents per year for every person in the world.- Many people have health problems from eating too much• Overnutrition occurs when food energy intake exceeds energy use, causing excess body fat. • Face similar health problems as those under: lower life expectancy, greater susceptibility to

disease and illness, and lower productivity and life quality. • Globally about 925 million people have health problems because they do not get enough to

eat, and about 1.1 billion people face health problems from eating too much.• About 68% of American adults are overweight and half of those people are obese.

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• Obesity plays a role in four of the top ten causes of death in the United States—heart disease, stroke, Type 2 diabetes, and some forms of cancer.

- Food production has increased dramatically• About 10,000 years ago, humans began to shift from hunting for and gathering their food to

growing it and raising animals for food and labor.• Today, three systems supply most of our food.

– Croplands produce mostly grains. – Rangelands, pastures, and feedlots produce meat.– Fisheries and aquaculture provide us with seafood.

• About 66% of the world’s people survive primarily by eating rice, wheat, and corn. – Only a few species of mammals and fish provide most of the world’s meat and seafood.

• Since 1960, there has been an increase in global food production from all three of the major food production systems because of technological advances.– Tractors, farm machinery and high-tech fishing equipment.– Irrigation.– Inorganic chemical fertilizers, pesticides, high-yield grain varieties, and industrialized

production of livestock and fish. - Industrialized crop production relies on high-input monocultures• Agriculture used to grow crops can be divided roughly into two types:

– Industrialized agriculture, or high-input agriculture, uses heavy equipment and large amounts of financial capital, fossil fuel, water, commercial inorganic fertilizers, and pesticides to produce single crops, or monocultures.• Major goal of industrialized agriculture is to increase yield, the amount of food

produced per unit of land.• Used on about 25% of the world’s cropland, mostly in more-developed countries,

and produces about 80% of the world’s food. – Plantation agriculture is a form of industrialized agriculture used primarily in tropical

less-developed countries.• Grows cash crops such as bananas, soybeans, sugarcane, coffee, palm oil, and

vegetables.• Crops are grown on large monoculture plantations, mostly for export to more-

developed countries.– Modern industrialized agriculture violates the three principles of sustainability by relying

heavily on fossil fuels, reducing natural and crop biodiversity, and neglecting the conservation and recycling of nutrients in topsoil.

- Traditional agriculture often relies on low-input polycultures• Traditional agriculture provides about 20% of the world’s food crops on about 75% of its

cultivated land, mostly in less-developed countries.• There are two main types of traditional agriculture.

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– Traditional subsistence agriculture supplements energy from the sun with the labor of humans and draft animals to produce enough crops for a farm family’s survival, with little left over to sell or store as a reserve for hard times.

– In traditional intensive agriculture, farmers increase their inputs of human and draft-animal labor, animal manure for fertilizer, and water to obtain higher crop yields, some of which can be sold for income.

• Many traditional farmers grow several crops on the same plot simultaneously, a practice known as polyculture. – Crop diversity reduces the chance of losing most or all of the year’s food supply to pests,

bad weather, and other misfortunes.– Crops mature at different times, provide food throughout the year, reduce the input of

human labor, and keep the soil covered to reduce erosion from wind and water.– Lessens need for fertilizer and water, because root systems at different depths in the

soil capture nutrients and moisture efficiently.– Insecticides and herbicides are rarely needed because multiple habitats are created for

natural predators of crop-eating insects, and weeds have trouble competing with the multitude of crop plants.

– On average, such low-input polyculture produces higher yields than does high-input monoculture.

- A closer look at industrialized crop production• Farmers can produce more food by increasing their land or their yields per acre.• Since 1950, about 88% of the increase in global food production has come from using high-

input industrialized agriculture to increase yields in a process called the green revolution.• Three steps of the green revolution:

– First, develop and plant monocultures of selectively bred or genetically engineered high-yield varieties of key crops such as rice, wheat, and corn.

– Second, produce high yields by using large inputs of water and synthetic inorganic fertilizers, and pesticides.

– Third, increase the number of crops grown per year on a plot of land through multiple cropping.

• The first green revolution used high-input agriculture to dramatically increase crop yields in most of the world’s more-developed countries, especially the United States, between 1950 and 1970.

• A second green revolution has been taking place since 1967. Fast-growing varieties of rice and wheat, specially bred for tropical and subtropical climates, have been introduced into middle-income, less-developed countries such as India, China, and Brazil.

Producing more food on less land has helped to protect some biodiversity by preserving large areas of forests, grasslands, wetlands, and easily eroded mountain terrain that might otherwise be used for farming.

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Largely because of the two green revolutions, world grain production tripled between 1961 and 2009.

People directly consume about 48% of the world’s grain production. About 35% is used to feed livestock and indirectly consumed by people who eat meat and meat products. The remaining 17% (mostly corn) is used to make biofuels such as ethanol for cars and other vehicles.

In the U.S., industrialized farming has evolved into agribusiness, as a small number of giant multinational corporations increasingly control the growing, processing, distribution, and sale of food in U.S. and global markets.

Since 1950 U.S. industrialized agriculture has more than doubled the yields of key crops such as wheat, corn, and soybeans without cultivating more land.

Americans spend only about 13% of their disposable income on food, compared to the percentages up to 50% that people in China and India and most other less-developed countries have to pay for food.

- Crossbreeding and genetic engineering produce varieties of crops and livestock• Crossbreeding through artificial selection has been used for centuries by farmers and scientists

to develop genetically improved varieties of crops and livestock animals.– Such selective breeding in this first gene revolution has yielded amazing results; ancient

ears of corn were about the size of your little finger, and wild tomatoes were once the size of grapes.

– Typically takes 15 years or more to produce a commercially valuable new crop variety, and it can combine traits only from genetically similar species.

– Typically, resulting varieties remain useful for only 5–10 years before pests and diseases reduce their efficacy.

• Modern scientists are creating a second gene revolution by using genetic engineering to develop genetically improved strains of crops and livestock.– Alters an organism’s genetic material through adding, deleting, or changing segments of

its DNA to produce desirable traits or to eliminate undesirable ones (gene splicing); resulting organisms are called genetically modified organisms.

– Developing a new crop variety through gene splicing is faster selective breeding, usually costs less, and allows for the insertion of genes from almost any other organism into crop cells.

– Currently, at least 70% of the food products on U.S. supermarket shelves contain some form of genetically engineered food or ingredients, but no law requires the labeling of GM products.

– Certified organic food, which is labeled as makes no use of genetically modified seeds or ingredients.

– Bioengineers plan to develop new GM varieties of crops that are resistant to heat, cold, herbicides, insect pests, parasites, viral diseases, drought, and salty or acidic soil. They

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also hope to develop crop plants that can grow faster and survive with little or no irrigation and with less fertilizer and pesticides.

- Meat production has grown steadily• Meat and animal products such as eggs and milk are good sources of high-quality protein and

represent the world’s second major food-producing system.• Between 1961 and 2010, world meat production—mostly beef, pork, and poultry—increased

more than fourfold and average meat consumption per person more than doubled.• Global meat production is likely to more than double again by 2050 as affluence rises and

more middle-income people begin consuming more meat and animal products in rapidly developing countries such as China and India.

• About half of the world’s meat comes from livestock grazing on grass in unfenced rangelands and enclosed pastures.

• The other half is produced through an industrialized system in which animals are raised mostly in densely packed feedlots and concentrated animal feeding operations (CAFOs), where they are fed grain, fish meal, or fish oil, which are usually doctored with growth hormones and antibiotics.

• Feedlots and CAFOs, and the animal wastes and runoff associated with them, create serious environmental impacts on the air and water.

- Fish and shellfish production have increased dramatically• The world’s third major food-producing system consists of fisheries and aquaculture.• A fishery is a concentration of particular aquatic species suitable for commercial harvesting in a

given ocean area or inland body of water.• Industrial fishing fleets harvest most of the world’s marine catch of wild fish.• Fish and shellfish are also produced through aquaculture—the practice of raising marine and

freshwater fish in freshwater ponds and rice paddies or in underwater cages in coastal waters or in deeper ocean waters.

• Some fishery scientists warn that unless we reduce overfishing and ocean pollution, and slow projected climate change, most of the world’s major commercial ocean fisheries could collapse by 2050.

- Industrialized food production requires huge inputs of energy• The industrialization of food production has been made possible by the availability of energy,

mostly from nonrenewable oil and natural gas.• Energy is needed to run farm machinery, irrigate crops, and produce synthetic pesticides and

synthetic inorganic fertilizers, as well as to process food and transport it long distances within and between countries.

• As a result, producing, processing, transporting, and consuming industrialized food result in a large net energy loss.

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- Producing food has major environmental impacts

• Spectacular increases in the world’s food production since 1950. The bad news is the harmful environmental effects associated with such production increases.

• According to many analysts, agriculture has a greater total harmful environmental impact than any human activity.

• These environmental effects may limit future food production and make it unsustainable. - Topsoil erosion is a serious problem in parts of the world• Soil erosion is the movement of soil components, especially surface litter and topsoil from one

place to another by the actions of wind and water.• Erosion of topsoil has two major harmful effects.

– Loss of soil fertility through depletion of plant nutrients in topsoil. – Water pollution in nearby surface waters, where eroded topsoil ends up as sediment.

This can kill fish and shellfish and clog irrigation ditches, boat channels, reservoirs, and lakes.

• By removing vital plant nutrients from topsoil and adding excess plant nutrients to aquatic systems, we degrade the topsoil and pollute the water, and thus alter the carbon, nitrogen, and phosphorus cycles.

- Drought and human activities are degrading drylands• Desertification in arid and semiarid parts of the world threatens livestock and crop

contributions to the world’s food supply.• Desertification occurs when the productive potential of topsoil falls by 10% or more because of

a combination of prolonged drought and human activities that expose topsoil to erosion.• The FAO’s 2007 report on the Status of the World’s Forests estimated that some 70% of

world’s arid and semiarid lands used for agriculture are degraded and threatened by desertification.

- Excessive irrigation has serious consequences• Irrigation boosts productivity of farms; roughly 20% of the world’s cropland that is irrigated

produces about 45% of the world’s food.• Most irrigation water is a dilute solution of various salts that are picked up as the water flows

over or through soil and rocks.• Repeated annual applications of irrigation water in dry climates lead to the gradual

accumulation of salts in the upper soil layers—a soil degradation process called salinization that stunts crop growth, lowers crop yields, and can eventually kill plants and ruin the land.

• Severe salinization has reduced yields on at least 10% of the world’s irrigated cropland, and almost 25% of irrigated cropland in the United States, especially in western states

• Irrigation can cause waterlogging, in which water accumulates underground and gradually raises the water table; at least one-tenth of the world’s irrigated land suffers from waterlogging, and the problem is getting worse.

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• Excessive irrigation contributes to depletion of groundwater and surface water supplies. - Agriculture contributes to air pollution and projected climate change• Agricultural activities create a lot of air pollution. • Account for more than 25% of the human-generated emissions of carbon dioxide, other

greenhouse gases.• Industrialized livestock production alone generates about 18% of the world’s greenhouse

gases; cattle and dairy cows release the greenhouse gas methane and methane is generated by liquid animal manure stored in waste lagoons.

• Nitrous oxide, with about 300 times the warming capacity of CO2 per molecule, is released in huge quantities by synthetic inorganic fertilizers as well as by livestock manure.

- Food and biofuel production systems have caused major losses of biodiversity• Natural biodiversity and some ecological services are threatened when forests are cleared and

grasslands are plowed up and replaced with croplands used to produce food or biofuels, such as ethanol.

• There is increasing loss of agrobiodiversity, the world’s genetic variety of animal and plant species.

• In the United States, about 97% of the food plant varieties that were available to farmers in the 1940s no longer exist, except perhaps in small amounts in seed banks and in the backyards of a few gardeners.

• The world’s genetic “library,” which is critical for increasing food yields, is rapidly shrinking.- There is controversy over genetically engineered foods• Controversy has arisen over the use of genetically modified (GM) food and other products of

genetic engineering.• Its producers and investors see GM food as a potentially sustainable way to solve world hunger

problems and improve human health.• Some critics consider it potentially dangerous “Frankenfood.”

– Recognize the potential benefits of GM crops.– Warn that we know too little about the long-term potential harm to human health and

ecosystems from the widespread use of such crops.– Warn that GM organisms released into the environment may cause some unintended

harmful genetic and ecological effects.– Genes in plant pollen from GM crops can spread among nonengineered species. The

new strains can then form hybrids with wild crop varieties, which could reduce the natural genetic biodiversity of wild strains.

– Most scientists and economists who have evaluated the genetic engineering of crops believe that its potential benefits will eventually outweigh its risks.

– Others have serious doubts about the ability of GM crops to increase food security compared to other more effective and sustainable alternative solutions.

- There are limits to expansion of the green revolution

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• Factors that have limited the current and future success of the green revolution:– Without huge inputs of inorganic fertilizer, pesticides, and water, most green revolution

and genetically engineered crop varieties produce yields that are no higher (and are sometimes lower) than those from traditional strains.

– High inputs cost too much for most subsistence farmers in less-developed countries.– Scientists point out that continuing to increase these inputs eventually produces no

additional increase in crop yields.– Since 1978, the amount of irrigated land per person has been declining, due to

population growth, wasteful use of irrigation water, soil salinization, and depletion of both aquifers and surface water, and the fact that most of the world’s farmers do not have enough money to irrigate their crops.

– We can get more crops per drop of irrigation water by using known methods and technologies to greatly improve the efficiency of irrigation.

– Clearing tropical forests and irrigating arid land could more than double the world’s cropland, but much of this land has poor soil fertility, steep slopes, or both.

– Cultivating such land usually is expensive, is unlikely to be sustainable, and reduces biodiversity by degrading and destroying wildlife habitats

– During this century, fertile croplands in coastal areas are likely to be flooded by rising sea levels resulting from projected climate change.

– Food production could drop sharply in some major food-producing areas because of increased drought and longer and more intense heat waves, also resulting from projected climate change.

- Industrialized meat production has harmful environmental consequences• Producing meat by using feedlots and other confined animal production facilities increases

meat production, reduces overgrazing, and yields higher profits. • Such systems use large amounts of energy (mostly fossil fuels) and water and produce huge

amounts of animal waste that sometimes pollute surface water and groundwater and saturate the air with their odors and emitting large quantities of climate-changing greenhouse gases into the atmosphere.

• Meat produced by industrialized agriculture is artificially cheap – harmful environmental and health costs are not included in the prices.

• Overgrazing and soil compaction and erosion by livestock have degraded about 20% of the world’s grasslands and pastures.

• Rangeland grazing and industrialized livestock production cause about 55% of all topsoil erosion and sediment pollution, and 33% of the water pollution that results from runoff from excessive inputs of synthetic fertilizers.

• The use of fossil fuels energy pollutes the air and water, and emits greenhouse gases.• Use of antibiotics is widespread in industrialized livestock production facilities.

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70% of all antibiotics used in the United States are added to animal feed to prevent the spread of diseases in crowded feedlots and CAFOs and to make the livestock animals grow faster.

– Widespread antibiotic use in livestock is an important factor in the rise of genetic resistance among many disease-causing microbes.• Reduces the effectiveness of some antibiotics used to treat infectious diseases in

humans. • Promotes the development of new and aggressive disease organisms that are

resistant to all but a very few antibiotics currently available.• Animal waste produced by U.S. meat is roughly 130 times that of its human population.

III. IMPROVED FOOD SECURITY & SUSTAINABLE FOOD PRODUCTION

- Use government policies to improve food production and security• Agriculture is a financially risky business because farmers have a good or bad year depending

on factors over which they have little control: weather, crop prices, crop pests and diseases, loan interest rates, and global markets.

• Governments use two main approaches to influence food production: – Control prices. – Provide subsidies.

• To improve food security, some analysts urge governments to establish special programs focused on saving children from the harmful health effects of poverty.– Immunizing more children against childhood diseases.– Preventing dehydration from diarrhea by giving infants a mixture of sugar and salt in

water. – Preventing blindness by giving children an inexpensive vitamin A capsule twice a year.

- Reduce soil erosion• Soil conservation involves using a variety of ways to reduce soil erosion and restore soil

fertility, mostly by keeping the soil covered with vegetation.• Some of the methods farmers can use to reduce soil erosion:

– Terracing and contour planting are ways to grow food on steep slopes without depleting topsoil.

– Strip cropping involves planting alternating strips of a row crop and another crop that completely covers the soil, called a cover crop.

– Alley cropping, or agroforestry involves one or more crops planted together in strips or alleys between trees and shrubs, which provide shade.

– Farmers can establish windbreaks, or shelterbelts, of trees around crop fields to reduce wind erosion.

– Conservation tillage farming by using special tillers and planting machines that drill seeds directly through crop residues into the undisturbed soil.

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– Retire the estimated one-tenth of the world’s marginal cropland that is highly erodible and accounts for the majority of the world’s topsoil erosion.

• Soil erosion in the United States. – A third of the country’s original topsoil is gone and much of the rest is degraded.– In 1935, the United States passed the Soil Erosion Act, which established the Soil

Conservation Service (SCS) as part of the USDA. • Now called the Natural Resources Conservation Service

– Farmers and ranchers were given technical assistance to set up soil conservation programs.

– U.S. farmers are sharply reducing some of their topsoil losses through a combination of conservation-tillage farming and government-sponsored soil conservation programs.

- Restore soil fertility• Topsoil conservation is the best way to maintain soil fertility, with restoring some of the lost

plant nutrients being the next option.• Organic fertilizer from plant and animal materials.

– Animal manure: the waste of cattle, horses, poultry, and other farm animals adding organic nitrogen, stimulating the growth of beneficial soil bacteria and fungi.

– Green manure: consists of freshly cut or growing green vegetation that is plowed into the topsoil to increase the organic matter and humus available to the next crop.

– Compost is produced when microorganisms in soil break down organic matter in the presence of oxygen.

• Organic agriculture uses only organic fertilizers and crop rotation to replenish the nutrients.• Synthetic inorganic fertilizers are usually inorganic compounds that contain nitrogen,

phosphorus, and potassium.– Inorganic fertilizer use has grown more than 900% since 1950; now about one-fourth of

the world’s crops.– Fertilizer runoff can pollute nearby bodies of water and coastal estuaries where rivers

empty into the sea. – They do not replace organic matter. To completely restore nutrients to topsoil, both

inorganic and organic fertilizers should be used.- Reduce soil salinization and desertification• One way to prevent and deal with soil salinization is to reduce the amount of water that is put

onto crop fields through use of modern efficient irrigation.– Drip, or trickle irrigation, also called microirrigation, is the most efficient way to deliver

small amounts of freshwater to crops precisely.– These systems drastically reduce freshwater waste because 90–95% of the water input

reaches the crops. – By using less freshwater, they also reduce the amount of harmful salt that irrigation

water leaves in the soil.

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• Reducing desertification is not easy because we can’t control the timing and location of prolonged droughts caused by changes in weather patterns.

• We can reduce population growth, overgrazing, deforestation, and destructive forms of planting, irrigation, and mining, which have left much land vulnerable to soil erosion and thus desertification.

• Work to decrease the human contribution to projected climate change, which is expected to increase severe and prolonged droughts in larger areas of the world during this century.

• Restoration via planting trees. - Produce meat more efficiently and eat less meat• Meat production and consumption account for the largest contribution to the ecological

footprints of most individuals in affluent nations. • If everyone in the world today was on the average U.S. meat-based diet, the current annual

global grain harvest could sustainably feed only about one-third of the world’s current population.

• More sustainable meat production and consumption involves shifting from less grain-efficient forms of animal protein, (beef, carnivorous fish), to more grain-efficient forms (poultry, herbivorous farmed fish).

• Eating less meat by having one meatless day per week.• Healthier to eat less meat.• Replace meat with a balanced vegetarian diet.

- Shift to more sustainable food production• Industrialized agriculture produces large amounts of food at reasonable prices, but is

unsustainable because it:– Relies heavily on fossil fuels.– Reduces biodiversity and agrobiodiversity.– Reduces the recycling of plant nutrients back to topsoil.

• More sustainable, low-input agriculture has a number of major components. – Organic farming.

• Sharply reduces the harmful environmental effects of industrialized farming and our exposure to pesticides.

• Encourages more humane treatment of animals used for food and is a more economically just system for farm workers and farmers.

• Requires more human labor than industrial farming.• Yields can be lower but farmers do not have to pay for expensive synthetic

pesticides, herbicides, and fertilizers; typically get higher prices for their crops.– Organic polyculture.

• A diversity of organic crops is grown on the same plot. • Use polyculture to grow perennial crops—crops that grow back year after year on

their own.

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• Helps to conserve and replenish topsoil, requires and wastes less water, and reduces the need for fertilizers and pesticides.

• Reduces the air and water pollution associated with conventional industrialized agriculture.

– Shift from using imported fossil fuel to relying more on solar energy for food production.• Five major strategies to help farmers and consumers make the transition to more sustainable

agriculture:1. Greatly increase research on more sustainable organic farming and perennial

polyculture, and on improving human nutrition. 2. Establish education and training programs in more sustainable agriculture for students,

farmers, and government agricultural officials. 3. Set up an international fund to give farmers in poor countries access to various types of

more sustainable agriculture. 4. Replace government subsidies for environmentally harmful forms of industrialized

agriculture with subsidies that encourage more sustainable agriculture. 5. Mount a massive program to educate consumers about the true environmental and

health costs of the food they buy. This would help them understand why the current system is unsustainable, and it would help build political support for including the harmful costs of food production in the market prices of food.

- Integrated pest management is a component of more sustainable agriculture• Many pest control experts and farmers believe the best way to control crop pests is a carefully

designed integrated pest management (IPM) program.• Farmers develop a carefully designed control program that uses a combination of cultivation,

biological, and chemical tools and techniques.• The overall aim of IPM is to reduce crop damage to an economically tolerable level.• Farmers first use biological methods (natural predators, parasites, and disease organisms) and

cultivation controls (such as rotating crops, altering planting time, and using large machines to vacuum up harmful bugs).

• They apply small amounts of insecticides—mostly based on those naturally produced by plants—only when insect or weed populations reach a threshold where the potential cost of pest damage to crops outweighs the cost of applying the pesticide.

• Broad-spectrum, long-lived pesticides are not used, and different chemicals are used alternately to slow the development of genetic resistance and to avoid killing predators of pest species.

• A well-designed IPM program can reduce synthetic pesticide use and pest control costs by 50–65%, without reducing crop yields and food quality.

• IPM can also reduce inputs of fertilizer and irrigation water, and slow the development of genetic resistance, because pests are attacked less often and with lower doses of pesticides.

• Disadvantages of IPM:

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It requires expert knowledge about each pest situation and takes more time than does using conventional pesticides.

Methods developed for a crop in one area might not apply to areas with even slightly different growing conditions.

– Initial costs may be higher, although long-term costs typically are lower than those of using conventional pesticides.

– Widespread use of IPM is hindered in the United States and a number of other countries by government subsidies for using synthetic chemical pesticides, as well as by opposition from pesticide manufacturers, and a shortage of IPM experts.

• The USDA could promote IPM three ways:– First, add a 2% sales tax on synthetic pesticides and use the revenue to fund IPM

research and education. – Second, set up a federally supported IPM demonstration project on at least one farm in

every county in the United States. – Third, train USDA field personnel and county farm agents in IPM so they can help

farmers use this alternative. – Because these measures would reduce its profits, the pesticide industry has vigorously,

and successfully, opposed them.- Three big ideas• About 925 million people have health problems because they do not get enough to eat and 1.1

billion people face health problems from eating too much.• Modern industrialized agriculture has a greater harmful impact on the environment than any

other human activity.• More sustainable forms of food production will greatly reduce the harmful environmental

impacts of industrialized food production systems while likely increasing food security.

LECTURE 4 - PART 2 : NON-RENEWABLE MINERALS & ENERGY

I. NONRENEWABLE MINERALS

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A. Mineral resources & Environmental effects of using them - We use a variety of nonrenewable mineral resources• A mineral resource is a concentration of naturally occurring material from the earth’s crust that

can be extracted and processed into useful products and raw materials at an affordable cost. – Found and extracted more than 100 minerals from the earth’s crust.– Examples are fossil fuels (such as coal), metallic minerals (such as aluminum and gold),

and nonmetallic minerals (such as sand and limestone).– Minerals are classified as nonrenewable resources.

• An ore is rock that contains a large enough concentration of a particular mineral—often a metal—to make it profitable for mining and processing.– High-grade ore contains a large concentration of the desired mineral.– Low-grade ore has a smaller concentration.– Aluminum (Al) is used for packaging and beverage cans and as a structural material in

motor vehicles, aircraft, and buildings.– Steel, an essential material used in buildings and motor vehicles, is a mixture (alloy) of

iron (Fe) and other elements that are added to give it certain properties.– Copper (Cu), a good conductor of electricity, is used for electrical and communications

wiring.– Gold (Au) is used in electrical equipment, tooth fillings, jewelry, coins, and some medical

implants.- Some environmental impacts of mineral use• Metals can be used to produce many products.• Life cycle of a metal—mining, processing, and using it—takes enormous amounts of energy and

water and can disturb the land, erode soil, produce solid waste, and pollute the air, water, and soil.

• The more accessible and higher-grade ores are usually exploited first. • As they are depleted, mining lower-grade ores takes more money, energy, water, and other

materials, and increases land disruption, mining waste, and pollution.- There are several ways to remove mineral deposits• Shallow mineral deposits are removed by surface mining by:

– Removing vegetation.– Removing the overburden or soil and rock overlying a useful mineral deposit.– Placing waste material set aside in piles, called spoils.

• Open-pit mining.• Strip mining is useful and economical for extracting mineral deposits that lie in large horizontal

beds close to the earth’s surface.– Area strip mining is used where the terrain is fairly flat; a gigantic earthmover strips

away the overburden, and a power shovel removes the mineral deposit.– Contour strip mining is used mostly to mine coal on hilly or mountainous terrain.

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• Mountaintop removal uses explosives, large power shovels, and huge machines called draglines to remove the top of a mountain and expose seams of coal.

• Subsurface mining removes minerals from underground through tunnels and shafts.- Mining has harmful environmental effects• Scarring and disruption of the land surface.

– Mountaintop removal destroys forests, buries mountain streams, and increases flood hazards. Wastewater and toxic sludge, produced when the coal is processed, are often stored behind dams in these valleys, which can overflow or collapse and release toxic substances such as arsenic and mercury.

– In the United States, more than 500 mountaintops have been removed to extract coal and the resulting spoils have buried more than 1,100 kilometers (700 miles) of stream.

– Surface mining in tropical forests and other tropical areas destroys or degrades vital biodiversity when forests are cleared and rivers are polluted with mining wastes.

– Produces toxic waste material such as lead dust, which can cause lead poisoning and irreversible brain damage in children.

• Subsurface mining disturbs less land than surface mining disturbs, and it usually produces less waste material. – Creates hazards such as cave-ins, explosions, and fires. – Miners often get diseases such as black lung, caused by prolonged inhalation of coal

dust in subsurface mines. – Causes subsidence—the collapse of land above some underground mines.

• Mining operations produce large amounts of solid waste and cause major water and air pollution. – Acid mine drainage occurs when rainwater that seeps through a mine or a spoils pile

carries sulfuric acid to nearby streams and groundwater. – Mining has polluted about 40% of western watersheds in the United States, and it

accounts for 50% of all the country’s emissions of toxic chemicals into the atmosphere. – Much of this degradation comes from leaking storage ponds built to hold a toxic sludge

that is produced from the mining and processing of metal ores.- Removing metals from ores has harmful environmental effects• Ore mining typically has two components:

– Ore mineral, containing the desired metal.– Waste material.

• Removing the waste material from ores produces waste piles called tailings.• Heating ores to release metals is called smelting.

– Without effective pollution control equipment, smelters emit enormous quantities of air pollutants, including sulfur dioxide and suspended particles.

• Chemicals can be used to remove metals from their ores. B. Supplies & sustainable use of nonrenewable resources

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- Mineral resources are distributed unevenly• The earth’s crust contains fairly abundant deposits of iron and aluminum.• Manganese, chromium, cobalt, and platinum are relatively scarce.• The earth’s geologic processes have not distributed deposits of nonrenewable mineral

resources evenly among countries.• Five nations—the United States, Canada, Russia, South Africa, and Australia—supply most of

the nonrenewable mineral resources used by modern societies.• Experts are concerned about four strategic metal resources—manganese, cobalt, chromium,

and platinum—which are essential for the country’s economy and military strength. The United States has little or no reserves of these metals.

- Supplies of nonrenewable mineral resources can be economically depleted• The future supply of nonrenewable minerals depends on two factors:

– The actual or potential supply of the mineral. – The rate at which we use it.– Minerals may become economically depleted when it costs more than it is worth to find,

extract, transport, and process the remaining deposits. Options when this occurs are:• Recycle or reuse existing supplies.• Waste less or use less.• Find a substitute or do without.

- Market prices affect supplies of nonrenewable minerals• Geologic processes determine the quantity and location of a mineral resource.• Economics determines what part of the known supply is extracted and used.• An increase in the price of a scarce mineral resource can lead to increased supplies and

encourage more efficient use.• Standard economic theory may not apply because most well-developed countries often use

subsidies, taxes, regulations, and import tariffs to control the supply, demand, and price of minerals.

• Most mineral prices are kept artificially low. - Is mining lower-grade ores the answer?• Extraction of lower grades of ore is possible due to new earth-moving equipment, improved

techniques for removing impurities from ores, and other technological advances in mineral extraction and processing.

• Mining low-grade ores is limited by:– Increased cost of mining and processing larger volumes of ore. – Increasing shortages of freshwater—which is needed to mine and process some

minerals—especially in arid and semiarid areas.– Environmental impacts of the increased land disruption, waste material, and pollution

produced during mining and processing.

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• Can use microorganisms that can break down rock material and extract minerals in a process called in-place, or in-situ mining or biomining.

- Can we get more of our minerals from the oceans?• Some ocean mineral resources are dissolved in seawater.• Low concentrations take more energy and money than they are worth. • Hydrothermal ore deposits are rich in minerals such as copper, lead, zinc, silver, gold, and

some of the rare earth metals.• Growing interest in deep-sea mining.• Manganese nodules cover large areas of ocean floor.

- We can find substitutes for some scarce mineral resources• Human ingenuity will find substitutes.• Current materials revolution in which silicon and other new materials, particularly ceramics

and plastics, are being used as replacements for metals. • Finding substitutes for scarce minerals through nanotechnology.

- We can recycle and reuse valuable metals• A more sustainable way to use nonrenewable mineral resources (especially valuable or scarce

metals such as gold, copper, and aluminum) is to recycle or reuse them.• Recycling has a much lower environmental impact than mining and processing ores.• Cleaning up and reusing items instead of melting and reprocessing them has an even lower

environmental impact.- We can use mineral resources more sustainably• Instead of asking how we can increase supplies of nonrenewable minerals, we should be

asking, how can we decrease our use and waste of such resources? • Since 1990, a growing number of companies have adopted pollution and waste prevention

programs that have led to cleaner production.

II. ENERGY

A. Fossil fuel - What are fossil fuels? Fossil fuels are the remains of ancient organisms changed into solid (coal), liquid (oil) or gas (natural gas)- Fossil fuels supply most of our commercial energy• The direct input of solar energy produces several other forms of renewable energy resources

that: wind, flowing water, and biomass.• Most commercial energy comes from extracting and burning nonrenewable energy resources

obtained from the earth’s crust. – 87% from carbon-containing fossil fuels (oil, natural gas, and coal). – 6% from nuclear power. – 8% from renewable energy resources—biomass, hydropower, geothermal, wind, and

solar energy.

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- Fuels for different purposesFive main purposes for fuels• Cooking• Transportation• Manufacturing• Heating/cooling• Electricity

Some fuels better for some purposes- We depend heavily on oil• Crude oil (petroleum), is a black, gooey liquid consisting of hundreds of different combustible

hydrocarbons along with small amounts of sulfur, oxygen, and nitrogen impurities. – Also known as conventional oil and as light or sweet crude oil. – Oil, coal, and natural gas are called fossil fuels because they were formed from the

decaying remains (fossils) of organisms that lived millions of years ago.• When the rate of crude oil production starts declining it is referred to as peak production for

the well.• Global peak production is the point in time when we reach the maximum overall rate of crude

oil production for the whole world.• After extraction, crude oil is transported to a refinery by pipeline, truck, or ship (oil tanker).• Crude oil is heated to different boiling points in a complex process called refining to separate it

into different layers, such as petrochemicals.- How long might supplies of conventional crude oil last?• Crude oil is now the single largest source of commercial energy in the world.• Proven oil reserves are identified deposits from which conventional crude oil can be extracted

profitably at current prices with current technology. • Geologists project that known and projected global reserves of conventional crude oil will be

80% depleted sometime between 2050 and 2100. The remaining 20% will likely be too costly to remove.

• Options include: look for more oil. use less oil. waste less oil. use other energy resources.

- Advantages of Oil• Have a system to distribute and use it set up• High energy level• Used in many products• Relatively low cost

- Disadvantages of Oil

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• Running Out (Nonrenewable)• Dependent of foreign sources• POLLUTION• Global Warming• International politics

- Natural gas• Mainly methane CH4 • Also

– Ethane C2H6

– Propane C3H8

– Butane C4H10

Formed like oil from buried animals and plants millions of years ago.- Natural gas is a useful and clean-burning fossil fuel• Natural gas is a mixture of gases of which 50 - 90% is methane (CH4).

– Has high net energy.– Versatile fuel that can be burned to heat indoor space and water, propel vehicles and

produce electricity.– Lies above most reservoirs of crude oil.– When a natural gas field is tapped, propane and butane gases are liquefied and

removed as liquefied petroleum gas (LPG).– Cleanest-burning among the fossil fuels, releasing much less CO2 per unit of energy than

coal, crude oil, and synthetic crude oil from tar sands and oil shale. - Advantages of Gas• Cleaner burning than coal or oil.• Emits far fewer CO2 per energy units• More efficient energy producer and plants are cheaper to build

- Disadvantages of Natural Gas• Nonrenewable• Highly flammable• Air pollution• Global warming• Can be a challenge to transport

- Coal is a plentiful but dirty fuel• Coal is a solid fossil fuel formed from the remains of land plants that were buried 300 – 400

million years ago and exposed to intense heat and pressure over those millions of years.• Coal is burned in power plants to generate about 42% of the world’s electricity, and burned in

industrial plants to make steel, cement, and other products. • The three largest coal-burning countries are China, the U.S., and India.• Coal is plentiful and cheap.

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• Mining and burning coal have severe impacts on the earth’s air, water, land, climate, and human health.

Coal-burning power and industrial plants are among the largest emitters of the greenhouse gas CO2.

Coal burning emits trace amounts of toxic and radioactive materials. Burning coal produces a highly toxic ash that must be safely stored, essentially forever. China uses three times as much coal as the U.S. and it has become the world’s leading

emitter of CO2 and of sulfur dioxide. Coal is cheap but most of the harmful environmental and health costs are not included

in the price. The clean coal campaign.

• Powerful U.S. coal companies and utilities oppose measures.• Publicity campaign built around the misleading notion of clean coal.

Burn coal more cleanly by adding costly air pollution control devices. There is no such thing as clean coal.

- Coal advantages• Most abundant fossil fuel.• Lots of energy• Relatively inexpensive.• U.S. has plenty of it for a while.• Power plants relatively cheap to build.

- Coal disadvantages• High environmental impact (air, water, land, acid rain)• Global warming, high CO2 emissions• Toxic mercury and radioactivity• Dangerous to mine

- Pollution, climate change, and public health• Burning fossil fuels releases carbon dioxide, which contributes to global climate change.• When coal and oil burn, sulfur dioxide and nitrogen oxides are released, which contribute to

smog and acid deposition.• Oil spills, equipment ruptures, and oil in runoff pollute waterways, oceans, and coastal areas.• Coal-fired power plants release mercury, which harms human health. • Crude oil contains trace amounts of lead and arsenic.

- Damage caused by extracting fuels• Mining :

• Humans risk lives and respiratory health.• Ecosystems are damaged by habitat destruction, extensive erosion, acid drainage, and

heavy metal contamination downslope of mines.

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• Oil and gas extraction :• Roads and structures built to support drilling break up habitats and harm ecosystems.• The longterm consequences of accidents can be uncertain or unpredictable

- Dependence on foreign sources• Fossil fuels are not evenly distributed over the globe, so some countries must import fuel

sources.• Nations that import fuel may be vulnerable to changes in fuel prices set by suppliers.• Nations can import less fuel by developing domestic oil sources and renewable energy sources.

B. Renewable energy resources - We can heat buildings and water with solar energy• Passive solar heating system absorbs and stores heat from the sun directly. • Active solar heating system uses energy from the sun by pumping a heat-absorbing fluid

through special collectors usually mounted on a roof or on special racks to face the sun. - We can cool buildings naturally• Open windows to take advantage of breezes and use fans to keep the air moving.• A living roof can make a huge difference in keeping a building cool.• Install superinsulation and high-efficiency windows.• Block the high summer sun with window overhangs or awnings. • Use a light-colored roof to reflect as much as 80% of the sun’s heat. • Use geothermal heat pumps for heating and cooling.

- We can concentrate sunlight to produce high-temperature heat and electricity• Solar thermal systems use different methods to collect and concentrate solar energy in order

to boil water and produce steam for generating electricity• The net energy yield for solar thermal systems is only about 3%, which means that they need

large government subsidies or tax breaks in order to compete in the marketplace with alternatives that have higher net energy yields.

• Inexpensive solar cookers focus and concentrate sunlight for cooking food and sterilizing water.

- We can use sunlight directly to produce electricity• Solar energy can be converted directly into electrical energy by photovoltaic cells, commonly

called solar cells.• Solar cells have no moving parts, are safe and quiet, and produce no pollution or greenhouse

gases during operation. • The material used in solar cells can be made into paper-thin rigid or flexible sheets that can be

incorporated into roofing materials and attached to a variety of surfaces such as walls, windows, and clothing.

• Generating electricity with solar cells could become nearly as efficient as using coal-burning power plants without producing the air pollutants and climate-changing CO2 emitted by those plants.

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- We can produce electricity from falling and flowing water• Hydropower uses the kinetic energy of flowing and falling water to produce electricity.• Indirect form of solar energy because it is based on the evaporation of water, which is part of

the earth’s solar-powered water cycle.• Most common approach to harnessing hydropower is to build a high dam across a large river to

create a reservoir.• Hydropower is the world’s leading renewable energy source for the production of electricity. In

order, the world’s top six producers of hydropower are China, Canada, Brazil, the U.S., Russia, and Norway.

• Some analysts expect that use of large-scale hydropower plants will fall slowly over the next several decades as many existing reservoirs fill with silt and become useless faster than new systems are built.

• Microhydropower generators are small floating turbines that use the power of flowing water to turn rotor blades, which spin a turbine to produce electric current. They provide electricity at a low cost with a very low environmental impact.

• Ocean tides and waves contain energy. Dams have been built across the mouths of some bays and estuaries to capture the energy in ocean water movement.

- Using wind to produce electricity is an important step toward sustainability• Wind turbines have been erected in large numbers at favorable sites to create wind farms • Since 1990, wind power has been the world’s second fastest-growing source of energy after

solar cells.• Wind turbines can be interconnected in arrays of tens to hundreds. These wind farms or wind

parks can be located on land or offshore. • In 2009, a Harvard University study estimated that wind power has the potential to produce 40

times the world’s current use of electricity.• Benefits:

Wind is widely distributed and inexhaustible Wind power is mostly carbon-free and pollution-free. A wind farm can be built within 9 to 12 months and expanded as needed. Homeowners can also use small and quiet wind turbines to produce their own

electricity. Wind power has a moderate-to-high net energy ratio.

• Areas with the greatest wind power potential are often far from cities so may require controversial upgrading and expansion of electrical grid systems.

• Winds can die down and thus require a backup source of power, such as natural gas, for generating electricity.

• Some people in populated areas oppose wind farms as being unsightly and noisy.• In windy parts of the U.S. Midwest and in Canada, farmers and ranchers are paid royalties for

each wind turbine located their land and can still grow crops or graze cattle.

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- We can produce energy by burning solid biomass• Biomass consists of plant materials (such as wood and agricultural waste) and animal wastes

that can be burned directly as a solid fuel or converted into gaseous or liquid biofuels.• Solid biomass is burned mostly for heating and cooking, but also for industrial processes and

for generating electricity. Wood, wood wastes, charcoal (made from wood), animal manure. In agricultural areas, crop residues (such as sugarcane stalks, rice husks, and corn cobs)

and animal manure are collected and burned. About 2.7 billion people in 77 less-developed countries face a fuelwood crisis and are

often forced to meet their fuel needs by harvesting wood faster than it can be replenished.

Plant fast-growing trees, shrubs, and perennial grasses in biomass plantations, but this can deplete soil nutrients and deplete or degrade biodiversity.

- We can convert plants and plant wastes to liquid biofuels• Liquid biofuels such as biodiesel (produced from vegetable oils) and ethanol (ethyl alcohol

produced from plants and plant wastes) are being used in place of petroleum-based diesel fuel and gasoline.

• Advantages of biofuels: While oil resources are concentrated in a small number of countries, biofuel crops can

be grown almost anywhere, and thus they help countries to reduce their dependence on imported oil.

– If these crops are not used faster than they are replenished by new plant growth, there is no net increase in CO2 emissions, unless existing grasslands or forests are cleared to plant biofuel crops.

– Biofuels are easy to store and transport through existing fuel networks and can be used in motor vehicles at little or no additional cost.

• The two most water-intensive ways to produce a unit of energy are irrigating soybean crops to produce biodiesel fuel and irrigating corn to produce ethanol.

• An alternative to corn ethanol is cellulosic ethanol, which is produced from inedible cellulose that makes up most of the biomass of plants.

In this process, enzymes are used to help convert the cellulose from widely available inedible cellulose materials such as leaves, stalks, and wood chips to sugars that are processed to produce ethanol.

A plant that could be used for cellulosic ethanol production is switchgrass, a tall perennial grass native to North American prairies that grows faster than corn.

Affordable chemical processes for converting cellulosic material to ethanol are still being developed and are possibly years away.

- Net energy

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Net energy = Total amount of energy available from the resources – the amount of energy used

Net energy ratio = Energy produced/Energy used - Energy conservation• Practice of reducing energy use to make fossil fuels last and to prevent environmental damage

• Transportation: Gas-efficient cars and higher gas prices could help conserve energy in the U.S.

• Personal choices: Individuals can save energy by turning off lights, taking public transit, and buying energy-efficient appliances.

- Six big ideas• Dynamic forces that move matter within the earth and on its surface recycle the earth’s rocks,

form deposits of mineral resources, and cause volcanic eruptions, earthquakes, and tsunamis.• The available supply of a mineral resource depends on how much of it is in the earth’s crust,

how fast we use it, the mining technology used to obtain it, its market prices, and the harmful environmental effects of removing and using it.

• We can use mineral resources more sustainably by trying to find substitutes for scarce resources, reducing resource waste, and reusing and recycling nonrenewable minerals.

LECTURE 5 - PART 1 : WATER RESOURCES AND WATER POLLUTION

I. WATER RESOURCES & ITS ISSUES Importance of water

Freshwater is relatively pure and contains few dissolved salts. Earth has a precious layer of water—most of it saltwater—covering about 71% of the earth’s

surface. Water is an irreplaceable chemical with unique properties that keep us and other forms of life

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Water helps to sculpt the earth’s surface, moderate climate, and remove and dilute wastes and pollutants.

Access to freshwater is a global health issue. Every day an average of 3,900 children younger than age 5 die from waterborne infectious diseases.

An economic issue – vital for reducing poverty and producing food and energy. A women’s and children’s issue in developing countries because poor women and girls often

are responsible for finding and carrying daily supplies of water. A national and global security issue because of increasing tensions within and between nations

over access to limited water resources that they share. An environmental issue because excessive withdrawal of water from rivers and aquifers results

in dropping water tables, lower river flows, shrinking lakes, and losses of wetlands.- Where is water found?• 71% of earth is covered in water• 97% of that is in oceans• Most of the remaining 3% fresh, mainly in ice caps and glaciers

- Water availability• About 0.024% is readily available to us as liquid freshwater in accessible groundwater deposits

and in lakes, rivers, and streams.• The rest is in the salty oceans, in frozen polar ice caps and glaciers, or in deep underground and

inaccessible locations.• Comparison of population sizes and shares of the world’s freshwater among the continents.

- Water sources• The world’s freshwater supply is continually collected, purified, recycled, and distributed in the

earth’s hydrologic cycle, except when:– Overloaded with pollutants.– We withdraw water from underground and surface water supplies faster than it is

replenished.– We alter long-term precipitation rates and distribution patterns of freshwater through

our influence on projected climate change.- Surface water• Surface water is the freshwater from precipitation and snowmelt that flows across the earth’s

land surface and into lakes, wetlands, streams, rivers, estuaries, and ultimately to the oceans.– Precipitation that does not infiltrate the ground or return to the atmosphere by

evaporation is called surface runoff.– The land from which surface water drains into a particular river, lake, wetland, or other

body of water is called its watershed, or drainage basin. - Ground water• Groundwater: Some precipitation infiltrates the ground and percolates downward through

spaces in soil, gravel, and rock until an impenetrable layer of rock stops this groundwater—one of our most important sources of freshwater.– The zone of saturation is where the spaces are completely filled with water.– The top of this groundwater zone is the water table.

- Aquifers

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• Aquifers: underground caverns and porous layers of sand, gravel, or bedrock through which groundwater flows—typically moving only a meter or so (about 3 feet) per year and rarely more than 0.3 meter (1 foot) per day.

• Worldwide, about 70% of the water we withdraw each year comes from rivers, lakes, and aquifers to irrigate cropland, industry uses another 20%, and residences 10%.

- Too little water• The main factors that cause water scarcity in any particular area are a dry climate, drought, too

many people using a water supply more quickly than it can be replenished, and wasteful use of water.

• More than 30 countries—mainly in the Middle East and Africa—now face water scarcity.• By 2050, 60 countries, many of them in Asia, with three-fourths of the world’s population, are

likely to be suffering from water stress.- Too much water: Floods• Some areas sometimes have too much water because of natural flooding by streams, caused

mostly by heavy rain or rapidly melting snow.• Removal of water-absorbing vegetation, especially on hillsides, which can increase flooding and

pollution in local streams, as well as landslides and mudflows.• Draining and building on wetlands, which naturally absorb floodwaters.• Natural events: heavy rainfall, melting snow are major causes of flooding. • Floodplain: the natural area around a river where flooding normally occurs.

- We can reduce flood risks• Floods provide several benefits.

– Create the world’s most productive farmland by depositing nutrient-rich silt on floodplains.

– Recharge groundwater and help to refill wetlands, thereby supporting biodiversity and aquatic ecological services.

• To improve flood control, we can rely less on engineering devices such as dams and levees and more on nature’s systems such as wetlands and natural vegetation in watersheds.

• Levees or floodwalls along the sides of streams contain and speed up stream flow, but they increase the water’s capacity for doing damage downstream.

• Dams can reduce the threat of flooding by storing water in a reservoir and releasing it gradually, but they also have a number of disadvantages.

II. INCREASED WATER SUPPLIES & SUSTAINABLE WATER USE - How can we increase water supplies?• Aquifers provide drinking water for nearly half of the world’s people.• Water tables are falling in many areas of the world because the rate of pumping water from

aquifers (mostly to irrigate crops) exceeds the rate of natural recharge from rainfall and snowmelt.– Withdrawing large amounts of groundwater causes the sand and rock in aquifers to

collapse. – Groundwater overdrafts near coastal areas can pull saltwater into freshwater aquifers.

The resulting contaminated groundwater is undrinkable and unusable for irrigation.• Groundwater overpumping can cause land to sink, and contaminate freshwater aquifers near

coastal areas with saltwater.- Large dams and reservoirs have advantages and disadvantages

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• Dams are structures built across rivers to block some of the flow of water. • Dammed water usually creates a reservoir, a store of water collected behind the dam.

- Water transfers can be wasteful and environmentally harmful• In many cases, water has been transferred into various dry regions of the world for growing

crops and for other uses. • Such water transfers have benefited many people, but they have also wasted a lot of water

and they have degraded ecosystems from which the water was taken.• Such water waste is part of the reason why many products include large amounts of virtual

water. - Removing salt from seawater is costly, kills marine organisms, and produces briny wastewater• Desalination involves removing dissolved salts from ocean water or from brackish water in

aquifers or lakes for domestic use.– Distillation involves heating saltwater until it evaporates (leaving behind salts in solid

form) and condenses as freshwater.– Reverse osmosis (or microfiltration) uses high pressure to force saltwater through a

membrane filter with pores small enough to remove the salt.• There are three major problems with the widespread use of desalination

– The high cost– Pumping large volumes of seawater kills many marine organisms and also requires large

inputs of energy to run the pumps.– Desalination produces huge quantities of salty wastewater that must go somewhere.

- Worldwide water use• Agriculture: 70%• Industry: 20%• Domestic use: 10%

- How can we use freshwater more sustainably?• Reduce freshwater waste

– An estimated 66% of the freshwater used in the world is unnecessarily wasted.– It is economically and technically feasible to reduce such water losses to 15%, thereby

meeting most of the world’s water needs for the foreseeable future.• Cut freshwater waste in irrigation

– About 60% of the irrigation water worldwide does not reach the targeted crops.• Cut freshwater waste in industry & homes

– Producers of chemicals, paper, oil, coal, primary metals, and processed food consume almost 90% of the water used by industry in the United States.

– Flushing toilets with freshwater is the largest use of domestic water in the US.– Studies show that 30–60% of the freshwater supplied in nearly all of the world’s major

cities in less-developed countries is lost, primarily through leakage in water mains, pipes, pumps, and valves.

- We need to use water more sustainably• Each of us can help bring about such a “blue revolution” by using and wasting less water to

reduce our water footprints. III. WATER POLLUTION - Water pollution comes from point and nonpoint sources

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• Water pollution is any change in water quality that harms humans or other living organisms or makes water unsuitable for human uses such as drinking, irrigation, and recreation.

• Point sources discharge pollutants at specific locations through drain pipes, ditches, or sewer lines into bodies of surface water.• Because point sources are located at specific places, they are fairly easy to identify,

monitor, and regulate.• Nonpoint sources are broad, diffuse areas, rather than points, from which pollutants enter

bodies of surface water or air.• Difficult and expensive to identify and control discharges from many diffuse sources.

• Agricultural activities are the leading cause of water pollution, including sediment from erosion, fertilizers and pesticides, bacteria from livestock and food-processing wastes, and excess salts from soils of irrigated cropland.

• Industrial facilities, which emit a variety of harmful inorganic and organic chemicals, are a second major source of water pollution.

• Mining is the third biggest source of water pollution. Surface mining disturbs the land by creating major erosion of sediments and runoff of toxic chemicals.

- Stream and river pollution• In most less-developed countries, stream pollution from discharges of untreated sewage,

industrial wastes, and discarded trash is a serious and growing problem. • Flowing rivers and streams can recover rapidly from moderate levels of degradable, oxygen-

demanding wastes through a combination of dilution and biodegradation of such wastes by bacteria.

• Laws enacted in the 1970s to control water pollution have greatly increased the number and quality of plants that treat wastewater—water that contains sewage and other wastes from homes and industries—in the United States and in most other more-developed countries.

- Lake and reservoir pollution• Lakes and reservoirs are generally less effective at diluting pollutants than streams.• Lakes and reservoirs are more vulnerable than streams to contamination by runoff or discharge

of plant nutrients, oil, pesticides, and nondegradable toxic substances such as lead, mercury, and arsenic.

• Many toxic chemicals and acids also enter lakes and reservoirs from the atmosphere.• Eutrophication refers to the natural nutrient enrichment of a shallow lake, estuary, or slow-

moving stream usually caused by runoff of plant nutrients such as nitrates and phosphates from surrounding land.

• An oligotrophic lake is low in nutrients and its water is clear. • Near urban or agricultural areas, human activities can greatly accelerate the input of plant

nutrients to a lake (cultural eutrophication).• Too many nutrients (nitrogen and phosphorous) in the water causes algal blooms and

decreased oxygen in water• Little or no oxygen• Causes “dead zones” in water

- Groundwater pollution• Groundwater pollution is a serious threat to human health.• Common pollutants such as fertilizers, pesticides, gasoline, and organic solvents can seep into

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• When groundwater becomes contaminated, it cannot cleanse itself of degradable wastes as quickly as flowing surface water does.

• Little is known about groundwater pollution because it is expensive to locate, track, and test aquifers.

- Pollution prevention is the only effective way to protect groundwater• Find substitutes for toxic chemicals. • Keep toxic chemicals out of the environment.• Install monitoring wells near landfills and underground tanks. • Require leak detectors on underground tanks. • Ban hazardous waste disposal in landfills and injection wells. • Store harmful liquids in aboveground tanks with leak detection and collection systems.

- There are many ways to purify drinking water• More-developed countries usually store surface water in a reservoir to increasing dissolved

oxygen content and allow suspended matter to settle, then pumped water to a purification plant and treat it to meet government drinking water standards.

• We have the technology to convert sewer water into pure drinking water. But reclaiming wastewater is expensive and it faces opposition from citizens and from some health officials who are unaware of the advances in this technology

• Simple measures can be used to purify drinking water:• Exposing a clear plastic bottle filled with contaminated water to intense sunlight can kill

infectious microbes in as little as three hours.• The Life Straw is an inexpensive portable water filter that eliminates many viruses and

parasites from water drawn into it. - Ocean pollution is a growing and poorly understood problem• 80-90% of municipal sewage from most coastal areas of less-developed countries, and in some

coastal areas of more-developed countries, is dumped into oceans without treatment.• Some U.S. coastal waters have found vast colonies of viruses thriving in raw sewage and in

effluents from sewage treatment plants and leaking septic tanks. • Scientists also point to the underreported problem of pollution from cruise ships.• Harmful algal blooms can result from the runoff of sewage and agricultural water.• Every year, because of harmful algal blooms, at least 400 oxygen-depleted zones form in

coastal waters around the world. - Residential areas, factories, and farms all contribute to the pollution of coastal waters- Ocean Pollution from Oil• Crude and refined petroleum reach the ocean from a number of sources and become highly

disruptive pollutants. – Visible sources are tanker accidents and blowouts at offshore oil drilling rigs. – The largest source of ocean oil pollution is urban and industrial runoff from land, much

of it from leaks in pipelines and oil-handling facilities. At least 37% of the oil reaching the oceans is waste oil, dumped, spilled, or leaked onto the land or into sewers by cities and industries, as well as by people changing their own motor oil.

- Reducing ocean water pollution• The key to protecting the oceans is to reduce the flow of pollution from land and air and from

streams emptying into these waters. IV. SOLUTIONS FOR WATER POLLUTION

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- Reducing surface water pollution from nonpoint sources• There are a number of ways to reduce nonpoint-source water pollution, most of which comes

from agriculture.– Reduce soil erosion by keeping cropland covered with vegetation.– Reduce the amount of fertilizer that runs off into surface waters and leaches into

aquifers by using slow-release fertilizer, using no fertilizer on steeply sloped land, and planting buffer zones of vegetation between cultivated fields and nearby surface waters.

– Organic farming can also help prevent water pollution caused by nutrient overload. – Control runoff and infiltration of manure from animal feedlots by planting buffers and

locating feedlots and animal waste sites away from steeply sloped land, surface water, and flood zones.

- Laws can help to reduce water pollution from point sources• Set standards for allowed levels of key water pollutants and require polluters to get permits

limiting how much of various pollutants they can discharge into aquatic systems.• Shifting the focus of the law to water pollution prevention instead of focusing mostly on end-

of-pipe removal of specific pollutants.• Greatly increased monitoring for violations of the law.• Much larger mandatory fines for violators.• Regulating irrigation water quality. • Expand the rights of citizens to bring lawsuits to ensure that water pollution laws are enforced.

- Sewage treatment reduces water pollution• In urban areas most waterborne wastes flow through a network of sewer pipes to wastewater

or sewage treatment plants.- There are sustainable ways to reduce and prevent water pollution• Most developed countries have enacted laws and regulations that have significantly reduced

point-source water pollution as a result of bottom-up political pressure on elected officials by individuals and groups.

• To environmental and health scientists, the next step is to increase efforts to reduce and prevent water pollution in both more- and less-developed countries, beginning with the question: How can we avoid producing water pollutants in the first place?

• This shift will require that citizens put political pressure on elected officials and also take actions to reduce their own daily contributions to water pollution.

- Three big ideas• One of the major global environmental problems is the growing shortage of freshwater in

many parts of the world.• We can use water more sustainably by cutting water waste, raising water prices, and

protecting aquifers, forests and other ecosystems that store and release water.• Reducing water pollution requires preventing it, working with nature to treat sewage, cutting

resource use and waste, reducing poverty, and slowing population growth.

LECTURE 5 - PART 2 : AIR POLLUTION - CLIMATE CHANGE & OZONE DEPLETION I. AIR POLLUTION 1. Major air pollution problems - The atmosphere consists of several layers• A thin envelope of gases surrounding the earth is called the atmosphere.

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– The troposphere is the atmospheric layer closest to the earth’s surface extending only about 17 kilometers (11 miles) above sea level at the equator and 8 kilometers (5 miles) over the poles. Clouds, rain, snow and all precipitation occur here.

– The atmosphere’s second layer is the stratosphere, which extends from about 17 to about 48 kilometers (from 11 to 30 miles) above the earth’s surface.

• Ozone (O3) is concentrated in a portion of the stratosphere called the ozone layer, found roughly 17–30 kilometers (11–19 miles) above sea level.– Stratospheric ozone is produced when some of the oxygen molecules there interact

with ultraviolet (UV) radiation emitted by the sun.– This “global sunscreen” of ozone in the stratosphere keeps out about 95% of the sun’s

harmful UV radiation from reaching the earth’s surface. - Air pollution comes from natural and human sources• Air pollution is the presence of chemicals in the atmosphere in concentrations high enough to

harm organisms, ecosystems, or human made materials, or to alter climate.– Natural sources include dust blown by wind, pollutants from wildfires and volcanic

eruptions, and volatile organic chemicals released by some plants.– Most human inputs of outdoor air pollutants come from the burning of fossil fuels in

power plants and industrial facilities (stationary sources) and in motor vehicles (mobile sources).

• Scientists classify outdoor air pollutants into two categories.– Primary pollutants are harmful chemicals emitted directly into the air from natural

processes and human activities.– Secondary pollutants react with one another and with other normal components of air

to form new harmful chemicals, called secondary pollutants. • Outdoor air pollution is a global problem, largely due to the sheer volume of pollutants

produced by human activities- What are the major outdoor air pollutants?• Carbon monoxide (CO) is a colorless, odorless, and highly toxic gas that forms from motor

vehicle exhaust, burning of forests and grasslands, tobacco smoke, and open fires and inefficient stoves used for cooking.

• Carbon dioxide (CO2) is a colorless, odorless gas.– About 93% of the CO2 in the atmosphere is the result of the natural carbon cycle. – The rest comes from human activities, primarily the burning of fossil fuels and the

clearing of CO2-absorbing forests and grasslands.• Nitrogen oxides (NO & NO2)and nitric acid.

– Nitric oxide (NO) is a colorless gas that forms when nitrogen and oxygen gas in air react at the high-combustion temperatures in automobile engines and coal-burning power and industrial plants.

– In the air, NO reacts with oxygen to form nitrogen dioxide (NO2), a reddish-brown gas.– Some of the NO2 reacts with water vapor in the air to form nitric acid (HNO3) and nitrate

salts (NO3–)—components of harmful acid deposition.

– Nitrous oxide (N2O) is a greenhouse gas. • Sulfur dioxide and sulfuric acid.

– Sulfur dioxide (SO2) is a colorless gas with an irritating odor.

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– About one third of the SO2 in the atmosphere comes from natural sources as part of the sulfur cycle.

– Human sources include combustion of sulfur-containing coal in electric power and industrial plants and oil refining and smelting of sulfide ores.

– In the atmosphere, SO2 can be converted to aerosols, which consist of microscopic suspended droplets of sulfuric acid (H2SO4) and suspended particles of sulfate (SO4

2–) salts that return to the earth as a component of acid deposition.

• Particulates.– Suspended particulate matter (SPM) consists of a variety of solid particles and liquid

droplets small and light enough to remain suspended in the air for long periods.– EPA classifies particles as fine, or PM-10 (with diameters less than 10 micrometers), and

ultrafine, or PM-2.5 (with diameters less than 2.5 micrometers).– 38% comes from human sources such as coal-burning power and industrial plants,

motor vehicles, road construction, and tobacco smoke.• Ozone.

– Ozone (O3), a colorless and highly reactive gas, is a major ingredient of photochemical smog.

– Ozone in the troposphere near ground level is often referred to as “bad” ozone, while ozone in the stratosphere as “good” ozone.

– Volatile organic compounds (VOCs).• Organic compounds that exist as gases in the atmosphere or that evaporate into

the atmosphere are called volatile organic compounds (VOCs).• Global methane emissions come from natural sources, mostly plants, wetlands,

and termites, while human sources include primarily rice paddies, landfills, oil and natural gas wells, and cows.

• Benzene and other liquids used as industrial solvents, dry-cleaning fluids, and components of gasoline, plastics, and other products.

- Burning coal produces industrial smog• Sixty years ago, cities such as London, England, and the U.S. cities of Chicago, IL, and

Pittsburgh, PA, burned large amounts of coal in power plants and factories and for heating homes and often for cooking food.

• People in such cities, especially during winter, were exposed to industrial smog consisting mostly of an unhealthy mix of sulfur dioxide, suspended droplets of sulfuric acid, and a variety of suspended solid particles in outside air. Those burning coal inside their homes were exposed to dangerous levels of indoor air pollutants.

• Today, urban industrial smog is rarely a problem in most more-developed countries using pollution controls.

• In industrialized urban areas of China, India, Ukraine, and some eastern European countries, large quantities of coal are still burned in houses, power plants, and factories with inadequate pollution controls.• Because of its heavy reliance on coal, China has some of the world’s highest levels of

industrial smog and 16 of the world’s 20 most polluted cities.- Sunlight plus cars equals photochemical smog• A photochemical reaction is any chemical reaction activated by light.

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• Photochemical smog is a mixture of primary and secondary pollutants formed under the influence of UV radiation from the sun.

• The formation of photochemical smog begins when exhaust from morning commuter traffic releases large amounts of NO and VOCs into the air over a city.

• The NO is converted to reddish-brown NO2, which leads to the name brown-air smog.• When exposed to ultraviolet radiation from the sun, some of the NO2 reacts in complex ways

with VOCs released by certain trees, motor vehicles, and businesses. • The resulting mixture of pollutants, dominated by ground-level ozone, usually builds up to peak

levels by late morning, irritating people’s eyes and respiratory tracts. • Some of its pollutants, known as photochemical oxidants, can damage lung tissue.• All modern cities have some photochemical smog, but it is much more common in cities with

sunny, warm, and dry climates, and a great number of motor vehicles.- Summary of major outdoor pollutants• Carbon oxides (CO and CO2)• Sulfur oxides (SO2)• Nitrogen oxides (NO and NO2)• Volatile organic compounds (VOCs – CFCs)• Suspended particulate matter (soot, dust, asbestos, lead etc.)• Photochemical oxidants (ozone O3)• Radioactive substances (Radon)• Hazardous air pollutants (carcinogens, etc.)

- Several factors can decrease or increase outdoor air pollution• Five natural factors help reduce outdoor air pollution.

– Particles heavier than air settle out as a result of gravitational attraction to the earth.– Rain and snow help cleanse the air of pollutants.– Salty sea spray from the oceans washes out many pollutants from air that flows from

land over the oceans.– Winds sweep pollutants away and mixes them with cleaner air.– Some pollutants are removed by chemical reactions.

• Six other factors can increase outdoor air pollution.– Urban buildings slow wind speed and reduce dilution and removal of pollutants.– Hills and mountains reduce the flow of air in valleys below them and allow pollutant

levels to build up at ground level.– High temperatures promote the chemical reactions leading to formation of

photochemical smog.– VOCs emissions from certain trees and plants in heavily wooded urban areas can play a

large role in the formation of photochemical smog.– Grasshopper effect—occurs when air pollutants are transported by evaporation and

winds from tropical and temperate areas through the atmosphere to the earth’s polar areas, where they are deposited.

– Temperature inversions occurs when a layer of warm air can temporarily lie atop a layer of cooler air nearer the ground.

- Acid deposition is a serious regional air pollution problem

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• Most coal-burning power plants, ore smelters, and other industrial facilities in more-developed countries use tall smokestacks, which reduce local air pollution, but can increase regional air pollution downwind.

• Prevailing winds may transport the primary pollutants SO2 and NOx as far as 1,000 kilometers (600 miles), forming secondary pollutants such as droplets of sulfuric acid, nitric acid vapor, and particles of acid-forming sulfate and nitrate salts.

• Descend to the earth’s surface in two forms:• Wet deposition consisting of acidic rain, snow, fog, and cloud vapor, and dry deposition

resulting in a mixture called acid deposition, or acid rain.• Dry acid deposition (sulfur dioxide gas and particles of sulfate and nitrate salts).

• Mixture of wet and dry is called acid deposition—sometimes called acid rain. - Acid deposition has a number of harmful effects• Damages statues and buildings, contributes to human respiratory diseases, and can leach toxic

metals (such as lead and mercury) from soils and rocks into lakes used as sources of drinking water.

• Toxic metals can accumulate in the tissues of fish which are eaten by people and other animals.• 45 U.S. states have issued warnings telling people to avoid eating fish caught from waters that

are contaminated with toxic mercury. • Harms aquatic ecosystems, and can leave lakes with few if any fish.• Indirectly kills trees by leaching essential plant nutrients such as calcium and magnesium from

soils and releasing ions of aluminum, lead, cadmium, and mercury, which are toxic to the trees, leaving them vulnerable to stresses.

- We know how to reduce acid deposition• The best solutions are prevention approaches that reduce or eliminate emissions of sulfur

dioxide, nitrogen oxides, and particulates.• Implementing these solutions is politically difficult.

- Indoor air pollution is a serious problem• In less-developed countries, the indoor burning of wood, charcoal, dung, crop residues, coal,

and other cooking and heating fuels in open fires or in unvented or poorly vented stoves exposes people to dangerous levels of particulate air pollution.

• Indoor air pollution is a serious problem in developed areas of all countries, mostly because of chemicals used in building materials and products.

• EPA studies have revealed some alarming facts about indoor air pollution. Levels of 11 common pollutants generally are two to five times higher inside U.S. homes

and commercial buildings than they are outdoors. Pollution levels inside cars in traffic-clogged urban areas can be up to 18 times higher

than outside levels. The health risks from exposure to such chemicals are magnified because most people in

developed urban areas spend 70–98% of their time indoors or inside vehicles.• The four most dangerous indoor air pollutants in more-developed countries are:

tobacco smoke formaldehyde emitted from many building materials and various household products radioactive radon-222 gas, which can seep into houses from underground rock deposits very small (ultrafine) particles of various substances in emissions from motor vehicles,

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- Air pollution is a big killer• Your respiratory system helps protect you from air pollution.• Prolonged or acute exposure to air pollutants, can overload or break down these natural

defenses. • Fine and ultrafine particulates get lodged deep in the lungs, contributing to lung cancer,

asthma, heart attack, and stroke. • Years of inhaling smoke polluted air can lead to other lung ailments such as chronic bronchitis

and emphysema, leading to acute shortness of breath.• At least 2.4 million people worldwide die prematurely each year from the effects of air

pollution.2. Solutions for air pollution - Laws and regulations can reduce outdoor air pollution• The United States provides an excellent example of how a regulatory approach can reduce air

pollution. • The U.S. Congress passed the Clean Air Acts in 1970, 1977, and 1990.

– The federal government established air pollution regulations for key pollutants that are enforced by states and major cities.

• Six major outdoor pollutants regulated:– Carbon monoxide– Nitrogen dioxide – Sulfur dioxide – Suspended particulate matter– Ozone– Lead

- We can emphasize pollution prevention• Greater emphasis on preventing air pollution.• Will not take place unless individual citizens and groups put political pressure on elected

officials to enact and enforce appropriate regulations. • Citizens can, through their purchases, put economic pressure on companies to get them to

manufacture and sell products and services that do not add to pollution problems.II. CLIMATE CHANGE 1. What is climate change? - Weather and climate are not the same• Weather consists of short-term changes in atmospheric variables, such as the temperature

and precipitation in a given area over a period of hours or days. • Climate is determined by the average weather conditions of the earth or of a particular area,

especially temperature and precipitation, over periods of at least three decades to thousands of years.

• One or two warmer or colder years or decades can result simply from changes in the weather; don’t necessarily tell us that the earth’s climate is warming or cooling.

• Climate scientists look at data on normally changing weather conditions to see if there has been a general rise or fall in any measurements such as average temperature or precipitation over a period of at least 30 years.

- Human activities emit large quantities of greenhouse gases

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• A natural process called the greenhouse effect occurs when some of the solar energy absorbed by the earth radiates into the atmosphere as infrared radiation (heat).

• Four greenhouse gases absorb the heat which warms the lower atmosphere and the earth’s surface, helping to create a livable climate.– Water vapor (H2O).– Carbon dioxide (CO2).– Methane (CH4).– Nitrous oxide (N2O).

• Since the beginning of the Industrial Revolution in the mid-1700s, human actions—mainly the burning of fossil fuels—have led to significant increases in the levels of greenhouse gases in the lower atmosphere.

- CO2 emissions play an important role• Never 390 ppm in last 420,000 years (possibly 20 million)• Continue to rise rapidly• Most CO2 in atmosphere is coming from burning fossil fuels like coal, oil and natural gas

– 42% coal power plants– 24% transportation– 20% industrial processes– 14% residential and commercial usages

• Major climate models indicate a need to prevent CO2 levels from exceeding 450 ppm—an estimated threshold, or irreversible tipping point, that could set into motion large-scale climate changes for hundreds to thousands of years.

2. Possible effects of warmer atmosphere - Severe drought is likely to increase• Severe and prolonged drought affects at least 30% of the earth’s land (excluding Antarctica).• By 2059 up to 45% of the world’s land area could experience extreme drought.• Effects of increased drought could include:

– The growth of trees and other plants declines. – Wildfires increase in frequency.– Declining stream flows and less available surface water– Falling water tables with more evaporation, worsened by farmers irrigating more to

make up for drier conditions.– Shrinking lakes, reservoirs, and inland seas.– Dwindling rivers.– Water shortages for 1–3 billion people.– Declining biodiversity.

- More ice and snow are likely to melt• The overall projected long-term trend is for the average summer ice coverage to decrease.• During the past 25 years, many of the world’s mountain glaciers have been melting and

shrinking at accelerating rates. – Mountain glaciers are sources of water for drinking, irrigation, and hydropower. – Water, food, and power shortages could threaten billions of people in Asia and South

America as these glaciers slowly melt over the next century or two.- Sea levels are rising

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• A 2008 U.S. Geological Survey report concluded that the world’s average sea level will most likely rise 0.8–2 meters (3–6.5 feet) by the end of this century and probably keep rising for centuries.

• Rising sea levels are due to the expansion of seawater as it warms, and to the melting of land-based ice.– degrade or destroy at least one-third of the world’s coastal estuaries, wetlands, and

coral reefs– disrupt many of the world’s coastal fisheries– cause flooding and erosion of low-lying barrier islands and gently sloping coastlines,

especially in U.S. coastal states - Extreme weather is likely to increase in some areas• Atmospheric warming will increase the incidence and intensity of extreme weather events.

– Kill large numbers of people.– Reduce crop production– Expand deserts

• A warmer atmosphere can hold more moisture, so other areas will experience increased flooding from heavy and prolonged precipitation.

• The consensus view of the effect of atmospheric warming on tropical storms and hurricanes is that projected atmospheric warming is likely lead to fewer but stronger hurricanes that could cause more damage.

- Climate disruption is a threat change will threaten biodiversity• Approximately 30% of the land-based plant and animal species assessed so far could disappear

if the average global temperature change exceeds 1.5–2.5ºC (2.7–4.5ºF).• The hardest hit will be:

– Plant and animal species in colder climates– Species at higher elevations– Plant and animal species with limited ranges – Those with limited tolerance for temperature change.

• The warmer climate would increase populations of insects and fungi that damage trees. - Agriculture could face an overall decline• Climate change models predict a decline in agricultural productivity in tropical and subtropical

regions. • Flooding of river deltas due to rising sea levels could reduce crop production in these areas and

fish production in nearby coastal aquaculture ponds. • Food production could also decrease in farm regions that are dependent on rivers fed by snow

and glacial melt, and in any arid and semiarid areas where droughts become more prolonged. - A warmer world is likely to threaten the health of many people• More frequent and prolonged heat waves in some areas will increase numbers of deaths and

illnesses, especially among older people, people in poor health, and the urban poor who cannot afford air conditioning.

• Hunger and malnutrition will increase in areas where agricultural production drops.• A warmer, CO2-rich world will favor rapidly multiplying insects, microbes, toxic molds, and fungi

that make us sick, and plants that produce pollens that cause allergies and asthma attacks.- What are our options?

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• Calling for urgent action at the national and international levels to curb greenhouse gas emissions by regulating and taxing such emissions will not work.

• Four major strategies to prevent & reduce greenhouse gas emission – Improve energy efficiency to reduce fossil fuel use, especially the use of coal. – Shift from nonrenewable carbon-based fossil fuels to a mix of low-carbon renewable

energy resources based on local and regional availability. – Stop cutting down tropical forests and plant trees to help remove more CO2 from the

atmosphere.– Shift to more sustainable and climate-friendly agriculture.

- Governments can help to reduce the threat of climate disruption• Governments can use six major methods to promote the solutions. • In December 1997, delegates from 161 nations met in Kyoto, Japan, to negotiate a treaty to

slow global warming and its projected climate disruption. – The Kyoto Protocol went into effect in 2005 with 187 of the world’s 194 countries (not

including the U.S.) ratifying the agreement by late 2009.• Costa Rica aims to be the first country to become carbon neutral by cutting its net carbon

emissions to zero by 2030.• China has one of the world’s most intensive energy efficiency programs.

- Individual choices make a difference• Each of us plays a part in the projected acceleration of atmospheric warming and climate

disruption during this century. Whenever we use energy generated by fossil fuels, for example, we add a certain amount of CO2 to the atmosphere. Each use of energy adds to an individual’s carbon footprint, the amount of carbon dioxide generated by one’s lifestyle.

III. OZONE DEPLETION - Our use of certain chemicals threatens the ozone layer• A layer of ozone in the lower stratosphere keeps about 95% of the sun’s harmful ultraviolet

(UV-A and UV-B) radiation from reaching the earth’s surface. • Measurements show considerable seasonal depletion (thinning) of ozone concentrations in the

stratosphere above Antarctica and the Arctic and a lower overall ozone thinning everywhere except over the tropics.

• Ozone depletion in the stratosphere poses a serious threat to humans, other animals, and some primary producers (mostly plants) that use sunlight to support the earth’s food webs.

• Problem began with the discovery of the first chlorofluorocarbon (CFC) in 1930 and later Freon.

Popular non-toxic, inexpensive coolants in air conditioners and refrigerators, propellants in aerosol spray cans, cleaners for electronic parts such as computer chips, fumigants for granaries and ship cargo holds, and gases used to make insulation and packaging.

CFCs are persistent chemicals that destroy the ozone layer.- CFCs• Used for decades• Each CFC molecule can destroy 100,000 ozone molecules over decades

- Why should we worry about ozone depletion?• More biologically damaging UV-A and UV-B radiation will reach the earth’s surface. • Causes problems with human health, crop yields, forest productivity, climate change, wildlife

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• Human health problems: – Damage to skin cells (including skin cancers)– Damage to eyes– UV Light damages DNA

- We can reverse stratospheric ozone depletion• The problem of ozone depletion has been tackled quite impressively.• In 2008, the area of ozone thinning was still near its record high of 29 million square kilometers

(11 million square miles), set in 2006.• Models indicate that even with immediate and sustained action.

– About 60 years for the earth’s ozone layer to recover the levels of ozone it had in 1980.– About 100 years for recovery to pre-1950 levels.

• In 1987, representatives of 36 nations met in Montreal, Canada, and developed the Montreal Protocol to cut emissions of CFCs.

• In 1992, adopted the Copenhagen Protocol, an amendment that accelerated the phase-out of key ozone-depleting chemicals signed by 195 countries.

• The ozone protocols set an important precedent by using prevention to solve a serious environmental problem.

- Three big ideas• All countries need to step up efforts to control and prevent outdoor and indoor air pollution.• Reducing the projected harmful effects of rapid climate disruption during this century requires

emergency action to increase energy efficiency, sharply reduce greenhouse gas emissions, rely more on renewable energy resources, and slow population growth.

• We need to continue phasing out the use of chemicals that have reduced ozone levels in the stratosphere and allowed more harmful ultraviolet radiation to reach the earth’s surface.

LECTURE 6 : ECONOMICS & ENVIRONMENTAL POLICY

I. ENVIRONMENTAL ECONOMICS - What is economics?• Economics is a social science that deals with the production, distribution, and consumption of

goods and services to satisfy people’s needs and wants.• Market-based economic system—buyers and sellers interact in markets to make economic

decisions about how goods and services are produced, distributed, and consumed.

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– In a free-market economic system, all economic decisions are governed solely by the competitive interactions of supply, demand, and price.

• Three types of capital, or resources, are used to produce goods and services. – Natural capital includes resources and services produced by the earth’s natural

processes, which support all economies and all life.– Human capital, or human resources, includes people’s physical and mental talents that

provide labor, innovation, culture, and organization.– Manufactured capital, or manufactured resources, are items such as machinery,

equipment, and factories made from natural resources with the help of human resources.

- Most economic systems use three types of resources to produce goods and services- Economists disagree over the importance of natural capital and the sustainability of economic growth• Economic growth for a city, state, country, or company is an increase in its capacity to provide

goods and services to people.• Economic development is the improvement of human living standards made possible by

economic growth.• High-throughput economies attempt to boost economic growth by increasing the flow of

natural matter and energy resources through their economic systems to produce more goods and services.

- The high-throughput economies of most of the world’s more-developed countries rely on continually increasing the flow of energy and matter resources to increase economic growth- Economists disagree over the importance of natural capital and the sustainability of economic growth• Neoclassical economists, following the ideas of Alfred Marshall (1842–1924) and Milton

Friedman (1912–2006) view the earth’s natural capital as a subset, or part, of a human economic system and assume that the potential for economic growth is essentially unlimited and is necessary for providing businesses with profits and workers with jobs.

• Ecological economists believe that: There are no substitutes for many vital natural resources such as air, water, and

biodiversity, or for nature’s free ecological services such as climate control, pest control, and nutrient recycling.

Economic systems are subsystems of the biosphere that depend heavily on the earth’s irreplaceable natural resources and services.

Conventional economic growth eventually will become unsustainable because it can deplete or degrade various irreplaceable forms of natural capital, and because it will exceed the capacity of the environment to handle the pollutants and wastes we produce.

• The models of ecological economists are built on three major assumptions. Resources are limited and should not be wasted; there are no substitutes for most types

of natural capital. We should encourage environmentally beneficial and sustainable forms of economic

development, and discourage environmentally harmful and unsustainable forms of economic growth.

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The harmful environmental and health effects of producing and using economic goods and services should be included in their market prices (full-cost pricing), so that consumers will have more accurate information about these effects.

• Many environmental economists argue that some forms of economic growth are not sustainable and should be discouraged through fine-tuning existing economic systems and tools.

- Ecological economists see all human economies as subsystems of the biosphere that depend on natural resources and services provided by the sun and earth- Most things cost more than we might think• The market price, or direct price, that we pay for something does not include most of the

indirect, or external, costs of harm to the environment and human health associated with its production and use.

• Hidden costs are the indirect or external costs that can have short- and long-term harmful effects on other people, on future generations, and on the earth’s life-support systems.

• Phase in shift to full-cost pricing so that environmentally harmful businesses would have time to transform themselves and consumers have time to adjust their buying habits.

• Resistance to full-cost pricing. Opposition from producers of harmful and wasteful products and services who would

have to charge more for them and might go out of business. Difficulty estimating environmental and health costs and how they might change in the

future. - Environmental economic indicators could help us reduce our environmental impact• Gross domestic product (GDP) is the annual market value of all goods and services produced

by all firms and organizations, foreign and domestic, operating within a country.• The per capita GDP is the GDP divided by the country’s total population at midyear.• GDP provides a standardized, useful method for measuring and comparing the economic

outputs of nations, and does not distinguish between goods and services that are environmentally or socially beneficial and those that are harmful.

• Environmental and ecological economists and environmental scientists call for new indicators help monitor environmental quality and human well-being.– Genuine progress indicator (GPI) is the GDP plus the estimated value of beneficial

transactions that meet basic needs, but in which no money changes hands, minus the estimated harmful environmental, health, and social costs of all transactions.

– In the U.S., between 1950 and 2004 the per capita GDP rose sharply and the per capita GPI stayed nearly flat and even declined slightly, which shows that even if a nation’s economy is growing, its people are not necessarily better off.

- We can reward environmentally sustainable businesses• Governments could phase in environmentally beneficial subsidies and tax breaks for:

– Pollution prevention.– Ecocity development.– Sustainable forestry, agriculture.– Sustainable water use.– Energy efficiency and renewable energy use.– Actions to slow projected climate change.

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• Use green taxes, or ecotaxes, to help include many of the harmful environmental and health costs of production and consumption in market prices.

• Three requirements for successful implementation of green taxes.– Phased in over 10–20 years to allow businesses to plan for the future.– Income, payroll, or other taxes would have to be reduced or replaced so that there is no

net increase in taxes.– The poor and middle class would need a safety net to help provide them with essentials

such as fuel and food.• Using green taxes to help reduce pollution and resource waste has advantages and

disadvantages- Environmental laws and regulations can discourage or encourage innovation• Environmental regulation is a form of government intervention in the marketplace that is

widely used to help control or prevent pollution and to reduce resource waste and environmental degradation.

• Laws that:– Set pollution standards.– Regulate harmful activities such as the release of toxic chemicals into the environment. – Protect certain irreplaceable or slowly replenished resources such as public forests.

• Currently most environmental laws enforced through a command-and-control approach (government sets rules and punishes for violations); often concentrating on cleanup instead of prevention.

• Incentive-based environmental regulations use the economic forces of the marketplace to encourage businesses to be innovative in reducing pollution and resource waste.

• Innovation-friendly environmental regulation sets goals and frees industries to meet them in any way that works, and allows enough time for innovation.

- Using the marketplace to reduce pollution and resource waste• One incentive-based regulation system allows the government to set acceptable pollution/use

limits or caps and gives or sells companies a certain number of tradable pollution or resource-use permits.

• The U.S. has used this cap-and-trade approach to reduce the emissions of sulfur dioxide and several other air pollutants.

• Effectiveness depends on how high or low the initial cap is set and on the rate at which the cap is reduced to encourage further innovation.

• Using tradable permits to reduce pollution and resource waste has advantages and disadvantages

- Reducing pollution and resource waste by selling services instead of things• A proposed new economic model would provide profits while greatly reducing resource use,

pollution, and waste for a number of goods by shifting from the current material-flow economy to a service-flow one.– Customers rent/lease services that goods provide.– A manufacturer or service provider makes more money if its product uses the minimum

amount of materials, lasts as long as possible, is energy efficient, produces as little pollution as possible in its production and use, and is easy to maintain, repair, reuse, or recycle

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– Since 1992, Xerox has been leasing most of its copy machines as part of its mission to provide document services instead of selling photocopiers.

- Reducing poverty can help us deal with environmental problems• Ways to reduce poverty and its harmful effects:

– Mount a massive global effort to combat malnutrition and the infectious diseases that kill millions of people prematurely.

– Provide primary school education for all children and for the world’s nearly 800 million illiterate adults.

– Stabilize population growth.– Sharply reduce the total and per capita ecological footprints. – Large investments in small-scale infrastructure and sustainable agriculture projects.– Encourage lending agencies to make small loans to poor people who want to increase

their income.- The Millennium Development Goals present challenges• Millennium Development Goals included sharply reducing hunger and poverty, improving

health care, achieving universal primary education, empowering women, and moving toward environmental sustainability by 2015.

• More-developed countries agreed to devote 0.7% of their annual national income toward achieving the goals.

• By 2009, only five countries—Denmark, Luxembourg, Sweden, Norway, and the Netherlands—had donated what they had promised; the U.S.—the world’s richest country—gives only 0.16% of its national income to help poor countries.

- We can use lessons from nature to shift to more environmentally sustainable economies• There is a sharp contrast between the beliefs of neoclassical economists and ecological

economists.• The best long-term solution to our environmental and resource problems is to shift from a

high-throughput (high-waste) to a more sustainable low-throughput (low-waste) economy. • Learning and applying lessons from nature can help us to design and manage more sustainable

low-throughput economies• Make this transition by:

reusing and recycling most nonrenewable matter resources using renewable resources no faster than natural processes can replenish them reducing resource waste by using matter and energy resources more efficiently reducing environmentally harmful forms of consumption emphasizing pollution prevention and waste reduction slowing population growth to keep the number of matter and energy consumers

growing slowly. II. ENVIRONMENTAL POLICY - Certain principles can guide us in making environmental policy• Several principles designed to minimize environmental harm:

– The reversibility principle: Try not to make a decision that cannot be reversed later if ends up wrong.

– The net energy principle: Do not encourage the widespread use of energy alternatives or technologies with low net energy yields.

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– The precautionary principle: When substantial evidence indicates that an activity threatens human health or the environment, take precautionary measures to prevent or reduce such harm.

– The prevention principle: Whenever possible, make decisions that help to prevent a problem from occurring or becoming worse.

– The polluter-pays principle: Develop regulations and use economic tools such as green taxes to ensure that polluters bear the costs of dealing with the pollutants and wastes they produce (full-cost pricing).

– The environmental justice principle: Establish environmental policy so that no group of people bears an unfair share of the burden created by pollution, environmental degradation, or the execution of environmental laws.

- Individuals can influence environmental policy• History shows that significant change usually comes from the bottom up, when individuals join

together to bring about change.• At a fundamental level, all politics is local; what we do to improve environmental quality in our

own neighborhoods, schools, and work places has national and global implications.• “Think globally; act locally.”

- Citizen environmental groups play important roles• The spearheads of the global conservation, environmental, and environmental justice

movements are the tens of thousands of nonprofit NGOs working at the international, national, state, and local levels. – Grassroots groups with just a few members.– Mainline organizations like the World Wildlife Fund (WWF), a 5-million-member global

conservation organization, which operates in 100 countries.– Groups with large memberships include Greenpeace, the Nature Conservancy,

Conservation International, and the Grameen Bank.- Students and educational institutions can play important environmental roles• Since the mid-1980s, there has been a boom in environmental awareness on U.S. college

campuses and in public and private schools across the U.S.. • Students, faculty, and administration work together to make environmental improvements.

– Environmental audits of campuses or schools gather data on practices affecting the environment and are used it to propose changes.

– Environmentally sustainable practices usually save money in the process.- Environmental security is as important as military and economic security• Ecologists and many economists point out that all economies are supported by the earth’s

natural capital. • Serious new threats to global and national military and economic security are the potential for

rapid climate change, increasing hunger and malnutrition, spreading water shortages, and environmental degradation.

• There is an increase in the number of failing states where governments can no longer provide security and basic services such as education, health care, and safe supplies of water for their citizens.

• The United Nations houses a large family of influential organizations including: the U.N. Environment Programme (UNEP). the World Health Organization (WHO).

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the U.N. Development Programme (UNDP). the Food and Agriculture Organization (FAO).

• Other organizations that make or influence environmental decisions include the World Bank, the Global Environment Facility (GEF) and the World Conservation Union (IUCN).

• These and other international organizations have played important roles in: Expanding global understanding of environmental issues; Gathering and evaluating environmental data. Developing and monitoring international environmental treaties. Providing grants and loans for sustainable economic development and reducing poverty. Helping more than 100 nations to develop environmental laws and institutions.

III. MORE SUSTAINABLE LIVING - We can become more environmentally literate• Increase literacy by understanding three important ideas:

– Natural capital matters because it supports the earth’s life and our economies.– Our ecological footprints are immense and are expanding rapidly.– Ecological and climate change tipping points are irreversible and should never be

crossed.- We can learn from the earth• Appreciation for ecological, aesthetic, and spiritual value of nature.• Not simply a lack of environmental literacy but also many people lack intimate contact with

nature and have a limited understanding of how it sustains us.• Humans have more power than ever before to disrupt nature.• Direct experiences with nature reveal parts of the complex web of life that cannot be built with

technology or in a chemical lab, bought with money, or reproduced with genetic engineering.• The healing of the earth and the healing of the human spirit are one and the same.

- We can live more simply and lightly on the earth• Sustainability is about sustaining the entire web of life.• Ethical guidelines for achieving more sustainable and compassionate societies by converting

environmental concerns, literacy, and wisdom into environmentally responsible actions:– Use the three principles of sustainability to mimic the ways in which nature sustains

itself.– Do not deplete or degrade the earth’s natural capital.– Do not waste matter and energy resources.– Protect biodiversity.– Repair ecological damage that we have caused.– Leave the earth in as good a condition as we found it, or better.

• People who have a habit of consuming excessively should to learn how to live more simply and sustainably.– Seeking happiness through the pursuit of material things is considered folly by almost

every major religion and philosophy.– Modern advertising persistently encourages people to buy more and more things to fill a

growing list of wants as a way to achieve happiness.– Mark Twain put it: “Civilization is the limitless multiplication of unnecessary necessities.”

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• A growing number of people really want is more community, greater and more fulfilling interactions with family, friends, and neighbors, and a greater opportunity to express their creativity and to have more fun.

• Some affluent people are adopting a lifestyle of voluntary simplicity, in which they seek to learn how to live with much less than they are accustomed to having. – A life based mostly on what one owns is not fulfilling.– Living with fewer material possessions and using products and services that have a

smaller environmental impact – Instead of working longer to pay for bigger vehicles and houses, they are spending more

time with their loved ones, friends, and neighbors. – Shifting from a culture of “faster, bigger, and more” to one of “slower, smaller, and

less.” - We can bring about a sustainability revolution during your lifetime• Time for an environmental or sustainability revolution.• Three social science principles of sustainability:

– Full-cost pricing (from economics): in working toward this goal, we would find ways to include in market prices the harmful environmental and health costs of producing and using goods and services.

– Win-win solutions (from political science): by focusing on solutions that will benefit the largest possible number of people, as well as the environment, we might learn to work together consistently in dealing with environmental problems.

– A responsibility to future generations (from ethics): through this principle, we would accept our responsibility to leave the planet’s life-support systems in at least as good a shape as what we now enjoy, for all future generations.

- Three big ideas• A more sustainable economic system would include the harmful environmental and health

costs of producing and using goods and services in their market prices, subsidize environmentally beneficial goods and services, tax pollution and waste instead of wages and profits, and reduce poverty.

• Individuals can work together to become part of the political processes that influence how environmental policies are made and implemented.

• Living more sustainably means becoming environmentally literate, learning from nature, living more simply, and becoming active environmental citizens.

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