Lecture 08

Environmental Science


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  Magic Fun With Food 
History of Food

      There are many Food Myths and Truths concerning the foods we eat. The history of human population growth is tied closely to agricultural development. Early societies consisted of hunters and gatherers who relied entirely on natural plant and animal products to satisfy their needs. Modern agricultural practices have resulted from the technological developments, scientific research, and exploration undertaken between 1450 and 1700. It was during the latter part of this period that new foods were introduced into various parts of the world. With this expansion, Europe began to grow three of the world’s great food plants, potatoes, maize, and rice. Potatoes and maize came from the Americas and rice from the Orient. The New World also contributed beans, squash, avocados, pineapples, tomatoes, and cocoa to the diets of Europeans. The American Indians gave the world such nonfoods as tobacco, rubber, and certain cottons. To the New World the Europeans brought wheat, onions, grape vines, and sugar cane along with domestic animals which included horses, dogs, pigs, cattle, chickens, sheep, and goats.

      Food production began to increase in the 1850s as a result of agricultural research. Knowledge of soil nutrients, development of synthetic fertilizers, the discovery of the role of microorganisms (such as nitrogen fixing bacteria), and the development of irrigation techniques all improved yields. Earlier agricultural practices influenced only the local ecosystem, but the more recent methods of fertilization, pesticide application, and energy use have affected global ecosystems. Other examples of disruption of ecosystems include overgrazing, which often causes topsoil to erode, and doubling the yield, which can require a tenfold increase in fertilizer. Industrialized agricultural practices result in air, land, and water pollution. Monocultures, fields of single crops, are more susceptible to pests than the natural communities they replace.

      Efforts are currently underway to rectify many of the undesirable effects of modern agriculture. By limiting the number of grazing animals per acre, soil erosion is retarded. Some farmers regularly rotate their crops to avoid depleting soil nutrients and sustain areas of natural vegetation in woodlots and fencerows to maintain natural ecological systems.

At a global level, human population growth is the dominant cause of the greater demand for food. A United Nations study concluded that food output must continue at that rate or a little higher to keep pace with population growth. The annual growth of food production has been just under two percent, a struggle to keep up with the additional people. Compounding the problem has been the lack of growth of per capita income since many poor cannot afford the available food items.

      Food supplies are not evenly distributed throughout the world. North American countries have become the dominant grain exporters. Imports increased in parts of Africa, the Middle East, and East Asia, at the same time that the USSR and Eastern Europe also expanded imports.

      The growing affluence of some people in the world is another major drain on the world food supply. Of all grain produced in the world, about 52 percent is consumed directly by people. Food for livestock takes up a considerable share of the remainder. In poor countries, the annual availability of grain per person is about 171 kilograms per year. Most of this is consumed directly.

       Global food production has increased greatly over the last twenty years but conventional agriculture uses more soil, water, plant, animal and energy resources and causes more environmental damage than any other human activity.  World food production has complex interactions between food production, population growth, poverty, environmental effects, economics, political systems and ethics.  Producing food faster than population growth does not solve hunger problems.  People have to have land to grow their own food or income to buy food.  Chronic hunger and famine are due to lack of access to food not from food shortage.


Green Revolution          Green Revolution and Subsistence Farming in India

      The development of strains of grain useful in many of the world’s highly populated areas began in 1944, when four young American plant scientists went to Mexico to help its impover­ished agricultural program. Twenty-six years later one of those four scientists, Dr. Norman E. Borlaug, was awarded the Nobel Peace Prize for his work. The introduction of high-yield grain varieties on a commercial scale to many less developed countries in the mid- to-late 1960s was called the Green Revolution. India, for example, began growing varieties of wheat which increased total yield by 50 to 100 percent, while new varieties of rice increased yields 10 to 20 percent.

      If the Green Revolution was so successful in India, why did world crop production fall? As with so many developments involving people and their environment, a whole array of physical factors, such as climate and environmental limitations, as well as political, economic, and cultural factors played a part. More people were eating than ever before, but more people were also starving. Food production simply was not keeping up with the population growth. In addition, a small percentage of the world’s population began consuming an increasingly larger proportion of the world’s food.

      The Green Revolution can continue to provide more food if technical problems are resolved, but it is not a panacea to the population-versus-environment problem. The environment and the balance of nature must be considered when we use these agricultural practices. The Green Revolution cannot indefinitely provide a food supply for an ever increasing number of people, and perhaps it should not if we want to solve the other problems besides hunger caused by increasing populations.


Biotechnology              Genetic Engineering                  Genetic Diversity

      Although not new, biotechnology is adding new dimensions to the production of world foods. Biotechnology has greater potential than the Green Revolution to change food production. The basis of biotechnology is the ability to manipulate the chemicals of reproduction. Many genetic engineering companies are engaged in the business of modifying the genetic material of plants and animals to produce faster-growing varieties, disease resistant plants, bacteria that will remove wastes from garbage, plants that will withstand adverse climatic conditions.

      There have been a number of success stories in the field of biotechnology. Cereal crops have been developed in Australia that live and produce in arid areas. In Canada corn and wheat are being tested that can grow in the harsh prairie winters. Faster growing, more efficient bacteria are now used in the fermenting process, thus requiring fewer steps and less equipment.

      All these rapid changes naturally cause concern about the negative aspects of biotechnology and the possibility of developing forms of life that will be harmful to the environment.


Food Additives

      Additives have been used for centuries to pre­serve food and to make it more palatable. Examples include salt brine to preserve fish and smoke to treat meat. All forms of food additives have increased in use since World War II be­cause of the development of large processing and food distribution centers. The use of prepared foods and the large number of meals eaten away from home have also contributed to greater use of food additives.

      What are food additives? They include all substances that can become a component of the food or affect any of its characteristics, such as flavor. They are classified as nutrients, preservatives, antioxidants, thickening agents, emulsifiers, drying substances, flavor enhancers, or coloring agents.

      Some people are concerned about the use of too many additives. They would prefer natural foods with no additives. Such an approach, while admirable, has some pitfalls. Without additives, many foods would start decaying and would cause sickness if eaten. Because people prefer special flavors, processors try to capture these flavors in food products. Taste buds located on our tongues recognize four basic tastes: sweet, salty, bitter, and sour. Different combinations of chemicals cause different receptor stimulations, so very slight chemical changes in foods can make foods much tastier.

      The U.S. Food and Drug Administration (FDA) was given authority in 1906, but the real food regulation provisions were established in the Food and Color Additives Amendment of 1958. At this time, evidence of the safety of food additives was required before the FDA would approve their use. In 1959 the FDA published a list of some 600 substances generally regarded as safe because they had been used safely for many years. In 1969, cyclamates had to be removed from the list because of the Delaney Clause. This clause, which stated that no additive should be considered safe if it induced cancer when ingested by humans or animals, became a provision of the 1958 Food and Color Additives Amendment.

      The total number of food additives is immense. They are generally safe when taken in small amounts and as part of a balanced diet. Most problems develop when a substance is not properly tested or when it is eaten in such excessive amounts that it creates physiological disorders. Although most people are concerned about the effects of food additives, few know what to do about them. Eating a balanced diet of a variety of foods and a minimum amount of self-additives (salt and sugar) is a good approach. People should understand how their bodies react to different additives and avoid those that cause problems. Asthmatics, for example, should avoid sulfur additives.

      Another additive group is artificial colorings. People often associate a specific color with a particular product, so butchers add a coloring agent to make meats red and margarine is colored yellow to look like butter. Florida oranges, which have big green splotches when they are picked, are colored orange to compete with the more orange California ones. If the Florida oranges were held until they turned orange, they would spoil before reaching the consumer.


World Food Supply

The supply of food available for consumption is determined by a number of controllable and uncontrollable factors. Weather and the amount of suitable land for farming have always been factors, and government controls and technology are playing an increasing role in the world food supply. The types of farming equipment and fertilizers used as well as research which produces such major changes as the Green Revolution are important controlling factors.

      Another controlling power is world governments. Within the United States, many forms of incentive payments are made to farmers for increasing or decreasing their crop production or land use. Parity is also a government pay­ment program that influences crop production. In 1978 and 1979, many farmers wanted the government to guarantee a price for their product regardless of the market price. This meant that the U.S. government would have to make up the difference between the price the farmers received and the parity price.

      Global food markets have become very complex. While some markets such as Japan and the European Common Market have tried to maintain stable prices by isolating themselves from other world markets, they have merely created new problems because they are not self-sufficient and other nations are unable to supplement their food needs. Likewise, while the United States responds to individual crises, it also prefers to remain isolated from the world food market.

       Because food production in the United States is influenced by food consumption, a decrease in consumption does not mean more food for the world’s hungry. For example, if everyone in the United States eliminated one hamburger from his menu each week for a year to send to the hungry, it is unlikely that those nations would get additional food. Rather, the production of beef and grain would probably drop the following year. The only way the beef would benefit others would be through an international agreement to transport it directly to the needy. The hungry nations, then, would have to be able to afford the price, and facilities would have to be available for transporting the food and storing it prior to usage. Furthermore, we would have to assume that Americans’ favorite, the hamburger, would be acceptable to the hungry. Indeed, redistribution of food is not an easy task. Think what that means in terms of the comment “Eat your food because the poor people in Asia are starving!”


Agricultural Land                      Types of  Agricultural Worldwide

Soil Types

      Because of different physical and biological factors, the soil formed in various parts of the world is quite different. In tropical soil, high rainfall and high temperatures remove many nutrients through leaching. The mineral nutrients in this ecosys­tem are tied up primarily in the forest vegetation.

      In northern coniferous forests, including parts of the northeastern United States, trees add little organic matter to the soil. Water falling on the litter becomes acidic and leaches away many minerals, making the soils unsuitable for agri­culture.

      Removing natural vegetation from a region by plowing or livestock grazing causes the topsoil to wash away during periods of rainfall. Litter that usually holds the rain water and allows it to seep into the natural pores of the soil is gone. Agricultural scientists estimate that on more than 10 percent of the world’s cropland erosion is so severe the land is essentially destroyed for further crop cultivation. In poorer countries, millions of acres of unproductive lands are abandoned yearly.

      Erosion can be controlled by planning and management. Prior to disturbing natural vegetation, it is necessary to understand the interrelationships of the particular ecosystem. Planting rapidly growing grasses helps prevent soil erosion. Crops can be planted to follow the land contours in areas of potential erosion problems. Leaving rows of the natural vegetation in place is also a useful practice to help avoid soil erosion. 

Soil Fertility

      The mineral elements essential for plant growth, with the exception of oxygen and carbon dioxide, are taken from the soil. Quantities of these elements in the soil indicate its fertility. Although the nutrient level is usually high in comparison with plant needs, all elements are not in a readily usable form. Soils, then, serve as a medium for bringing nutrient elements into the biological system.

      Many factors affect the nutrients that plants can get from soils. The size and arrangement of soil particles determine water flow and storage, air movement, and the soil’s ability to release nutrients to plants. Soils deficient in clay and organic matter are without structure and cannot hold water near the surface. For example, undisturbed forest soils can absorb 12.7 centimeters of rainfall each hour for ten hours, but cultivated soil can absorb no more than 3 centimeters per hour in the same time period.

      Organisms also contribute to soil fertility. Some are part of the detritus food chain and participate in the breakdown and release of nutrients from dead organic matter. They also play an important part in the forma­tion of humus, the decomposed organic material that contributes significantly to soil texture, water-holding capacities, and, in some cases, mineral binding. Some organisms release minerals from soil particles, making them available to plants. They are part of chemical reactions or create byproducts like acids that change the physical conditions of the soil. Earthworms and other larger organisms are important in maintaining aeration and texture.


Fertilizers and Insecticides

      Farmers have known for many centuries that the addition of fertilizers in the form of organic materials, including human and animal wastes or animal and plant parts, improved the yield of crops. Massive use of fertilizers, however, began with the manufacture of synthetic fertilizers in the late 1930's. Because plants require large amounts of nitrogen, phosphorus, and potassium, the primary soil micronutrients,  these three elements are the most common constituents of manufactured fertilizers. Total consumption varies with the region of the country and especially with the crop.

      The use of fertilizer has increased 240 percent in the United States because synthetic fertilizers were easily available and because the wornout, overused soil needed it so badly. The growth of fertilizer use was concentrated in the industrial countries; in 1981, industrial countries used 63 percent of all fertilizers and developing countries used 43 percent. The percentages are now shifting toward the developing countries.

        There is a conventional chemical method to control pests and there are alternatives based on working with nature.  A pest is a species that competes with man for food, invades homes and property, spreads disease or is a nuisance.  In natural ecosystems and polyculture agriculture, natural enemies control populations of 50 - 90% pest species.                

    Historically plants used chemicals to control pests before humans started to use chemicals.  Since ancient times man has used sulfur, arsenic, lead and mercury on crops to repel insects.  These compounds caused toxicity with animals and humans.  Second generation pesticides, such as DDT and other synthetic chemicals have been developed for crops and household use and are more effective.

        Pesticides have many benefits: prevent insect-transmitted diseases increase food supplies, lower food costs increase profits for farmer. Pests can be controlled by alternative means: crop rotation, trap crops, agro-forestry, polyculture genetically engineered resistant plants, crops biological control using predators, botanicals such as plant toxins, microbial plant pathogens, insect sex cycles altered by birth control, and hormones and pheromones.

      Integrated Pest Management (IPM) programs are being used by increasing numbers of agriculturists.  A mix of cultivation, biological and chemical methods is applied in proper sequence and proper timing.  Well designed IPM programs can reduce pest-induced crop loss by 50%.  Pesticide use and pest control costs can be reduced 50-90%.  I.P.M. requires expert knowledge, is slow acting and initially may cost more than conventional pesticides. Southeastern Michigan farmers are connected to Michigan State University Extension which programs the farmer's crop schedule and application by computer.  Often there will be computer sensors for wind, rain and insect traps for early detection of conditions that effect IPM programs. You can reduce your exposure to pesticides and their use.



      Oceans, covering some 71 percent of the earth’s surface, are an ancient source of food. Today many people mistakenly look to oceans as vast reservoirs of food. Since about 1950, sophisticated technological methods have been used to assure large catches of fish. Telecommunications, echo sounding, aerial communication, and temperature monitoring are used to locate fish, and electronic impulses and light attract them. Extensive information on fish migratory and schooling behavior aids the fishing industry. Modern fishing fleets include processing ships to prepare the catch for the consumer right at sea.

      Experts estimate that oceans could provide 110 million tons of biomass per year without destroying their populations. Nearly half the biomass currently removed is used for purposes other than food, such as manufacturing oil and fish meal which indirectly reach the tables of Western nations. Furthermore, much of the catch is not considered edible. There are over 21,000 species of living fish known, but only about ten are sought by commercial fisheries. These ten species are the major sources of food from the sea. They are large or appear in large schools, making them easy to locate and remove. A number of oceanic fishing efforts have led to over-fishing, depletion in stock, and an actual decline in catch. Other forms of seafood, such as crab, lobster, and abalone, continue to be used primarily for luxury foods.

      Aquaculture methods are being developed to raise fish in freshwater and saltwater ponds. Carp, eel, catfish, tilapias, and milkfish are currently raised in lakes and ponds and some rice paddies in Asia. Using waters for fish cultiva­tion much as we use land to grow livestock could make additional food available.


Energy and Food

      An important part of the food equation is energy production. Today few people in the developed countries come in contact with the soil for food. Neatly packaged food in supermarkets or food at fast-food restaurants are important parts of the American diet. Energy is expended to grow, harvest, process, transport, wholesale, retail, preserve, and cook these foods.

      Since 1940, food energy consumed per capita in the United States has increased only slightly. However, during that same period the amount of energy obtained in food per energy input has decreased. The actual yield in Calories per input of Calories has decreased because total energy use in the food system increased. All sectors of the food production cycle contributed to this rise.

      By looking at the Calorie input versus the Calorie output, we can see clearly that the food system in the United States is receiving an energy subsidy. The United States uses about ten Calories of fuel for each Calorie of food consumed. Despite recent hikes in energy costs, the United States still has relatively cheap energy. Perhaps this becomes more significant when we consider that 80 percent of the world’s total annual energy expenditure would be required to feed the world if the world had a food system like that in the United States. As the energy costs rise, however, U.S. food prices will continue to go up. Clearly, major changes are necessary, particularly in the developed coun­tries, if the food supply is to continue to sustain the present population level. Ultimate limits to the world food supply are imposed by land, water, energy, and nutrients.


 (A food calorie is defined as the amount of energy required to raise the temperature of one kilogram of water from l4.50c  to l5.50c at constant pressure. This is com­monly called the large calorie with a capital C. In phys­ics, the small calorie, with a lowercase c,  is defined as the amount of energy required to raise the temperature of one gram of water 10C. The nutritional calorie is equal to 1000 physics calories.)



      More important than food quantity is food quality. Human nutritional needs can be supplied by three categories of food substances:

1.   Proteins,  body-building substances for growth, repair, and maintenance. Increased energy use in the U.S. food system. Farm energy includes the manufacture of fertilizers, planting, and harvesting. Processing involves preparation, packaging, and transportation. Com­mercial and home energy use includes refrigeration, cooking, and storage. Food energy consumed increased from approximately 125 to 275 Calories.

2.   Vitamins and minerals are key elements or compounds in many essential body processes.

3.   Fats and carbohydrates are energy supply for the operation of the living body.



    Minerals Required in the Human Diet.
























      Food has a major role in individual health. The term “individual” is used because each person’s body responds differently to various foods. Although many people are allergic to some foods, they seldom associate the fact that excess gas or intestinal cramping can be symptoms of food allergies. Evidence has also shown that excessive amounts of sugar can cause antisocial behavior, stress, and depression. People who eat a lot of food high in fat content tend to have more health problems, particularly heart attacks. In order to lose weight, these people require a modification of their behavior patterns. Scientists realize that we have to be concerned with not only how food maintains physical health, but also how it controls human behavior.



      People who can not obtain enough food suffer from under-nutrition.  They are not starving but they are weakened and susceptible to infectious diseases.  To maintain good health and resist disease one needs the right amount of calories and adequate protein.  Humans do not store protein, as they do fats and carbohydrates, so protein is a limiting factor.  Worldwide chronic under-nutrition has decreased but in developing countries there still are one of every five persons who are chronically undernourished or malnourished.  This causes people to be disease prone and suffer premature deaths.  One of the Causes of Undernourishment and Malnourishment concerns our agriculture practices. Poverty not lack of food prevents poor people from growing or buying enough food even when it is available.  Poverty, malnutrition and disease form a tragic cycle. Developed countries suffer from over-nutrition in about 15% of the people.  Food additives in processed foods are of concern.  Lifestyle diseases such as heart disease, obesity and cancer can be related to diets and behaviors that are common in developed countries.  Thousands of chemicals are added to processed food in the U.S.

      We do produce more than enough food to meet basic nutritional needs of every person on earth, BUT food is not distributed equally among people.  Even in families, most food goes to working men.  Women and children are often underfed.  Developed countries can have pockets of poverty, hunger and malnutrition.

      Agriculture has a great effect on air, soil, water, biodiversity and human health.  Because of these harmful environmental effects, experts feel new food production and food distribution will not be able to keep up with current levels of population growth.

      Making sure food reaches hungry people is a huge task.  Food security ensures that all people have access to basic foods needed is different from food production.  Most poor farmers don't have enough land, money or credit to buy required food production supplies.  Current forms of the green revolution are more of a financial risk and often displace poor subsistence farmers from their land.  Mechanization reduces need for landless farm works.  More rural poor migrate to the overpopulated cities seeking means to earn basic needs.

      Because of over-fishing, pollution and population growth, marine catch is expected to decline.  Fish, as a potentially renewable resource is being harvested faster than it can replenish.  Degradation and destruction of wetlands, estuaries, coral reefs, salt marshes and mangroves threatens fish and shellfish populations.  Agriculture supplies one third of the world's fish production.  It is high efficient, has a high yield but is expensive, needs scientific knowledge and is susceptible to toxic runoff, fish predators and can degrade nearby aquatic areas.

      Although infant mortality rates have been lower in recent years, children under the age of five are still the major group of people affected by an improper diet. In many parts of the world, infants in particular die or develop poorly because of malnutrition due primarily to the parents’ ignorance. An individual who is undernourished might not exhibit a specific dietary deficiency, but could succumb to many bacterial, viral, or parasitic diseases because of a lowered body resistance.

      In many parts of the world torn by war and famine, over 50 percent of the infants one year old or less have marasmus, a disease caused by insufficient food. Marasmus produces a gradual wasting away of the body, generally associated with severe malnutrition or inadequate absorption of food and occurring mainly in young children. Marasmus results from a deficiency of many essential nutrients as well as proteins and Calories, causing its victims to suffer from muscle deterioration, loss of subcutaneous fat, and low body weight. This form of malnutrition often occurs in overpopulated city slum areas. Marasmus is increasing in poorer societies where breast-feeding is on the decline and in societies where there is not enough food to feed a weaned child.

      People in many parts of the world today have diseases associated with specific forms of malnutrition. Iron deficiency, which can result in anemia, is common in Africa, Asia, and Europe. In the Middle East, 25 to 75 percent of all children are anemic. Even in the United States, iron deficiency occurs in an estimated 20 percent of the population. Current evidence also shows that malnutrition is associated with a decrease in the birth rate. In some countries, the birth rate is declining because undernourished mothers have more miscarriages and fewer children.

      One out of every three people in the world today lives in a country that cannot produce enough food or afford to buy enough from another nation to feed itself. Nearly 70 percent of these people live in the four countries of India, Bangladesh, Pakistan, and Indonesia, with the rest in Africa and Latin America. Most major world nutritional deficiencies fall into two categories: inadequate energy and inadequate protein for bodybuilding processes. The aver­age person of 70 kilograms requires about 70 grams of protein per day, a level many nations do not achieve.



      While the Green Revolution has provided a greater supply of fast-growing grains in some nations, the population continues to outgrow the increase in food supply. Biotechnology can provide some alternative foods. Agricultural practices tend to alter natural feedback loops. As we continue to utilize more and more of the world’s food en­ergy, we approach the earth’s capacity for human population growth. In addition, many interrelated factors control the world food supply. Supply and demand are reflected in food prices, but weather and government controls have major impacts on production. Traditions, income, and local storage and transportation facilities influence people’s ability to obtain food.

      By improving the nutritive value of the food people presently use, malnutrition can be abated. Energy intake (Calories) must be balanced with the nutritive values of proteins, carbohydrates, fats, minerals, and vitamins in or­der to reduce suffering from malnutrition. But, How Many People can the Earth Sustain?

    To properly provide food for the world, we must make the best use of the soil in each region. Soil fertility must be maintained by proper crop rotation and fertilizer use. Better food production results from managing the natural resources of soil, water, minerals, and energy by an application of ecological principles.

      No single source, such as the ocean, can be considered a solution to our food problems. Food production can be increased by intensive agriculture, aquaculture, and more efficient use of lands throughout the year. However, we must supplement these methods with conservation measures, such as reducing our use of synthetic and fully prepared foods, in order to use valuable energy more efficiently and productively. One solution may be to "Eat Lower on the Food Chain".

      Agriculture is a high risk business so most governments provide assistance to farmers.  Governments keep food prices artificially low, or give farmers subsidies to stay in business and to increase food production.  A third policy is to eliminate most or all price controls and subsidies and allow the market to determine food prices and production.  This policy will cost the poor and middle class the most.  Many environmentalists feel all subsidies should be used only to reward farmers who protect the soil, conserve water, wildlife, protect and restore wetlands and forests.

      Sustainable or low input agriculture spends less money than high input agriculture on irrigation water, fertilizer and pesticides.  In developed countries such as U.S., it is difficult to shift to more environmentally sustainable forms of agriculture.  Political and ethical issues will determine if sustainable agriculture will revolutionize world agriculture.  People living in urban areas need to unite with rural people to achieve the market forces that can drive agricultural reforms.  Peoples of different areas can unite to provide the economic support that local food producers need to implement environmentally sound land uses.



Final Thoughts for the Course:                           The Four Elements