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Home , Pollution, Population density, World population, Zero population growth

The Basics of

About 12,000 years ago, several of other species' continue to look shifted from and gathering to to this day. The graph of recent farming. became the first and only species ever to control our own supply. Steady was the result of controlling the food supply. In population growth is referred to as a "J the absence of other limiting factors, any curve," because it starts out low and population will expand to the limit of its food skyrockets straight up. supply. This happens so reliably that it is considered a of . Present population reached 6.6 billion people By about 1800, major advances referred to as in 2007. At the present rate of growth nearly the “” were occurring. 77 million people are added per year. The Improvements to , settlement world adds a New York every month, a planning, division of labor, mathematics, Germany every year and a each and were all foundations of decade. The , with over 301 the industrial revolution. million people, is growing by nearly 3 million people each year. At this rate, we are one of Breakthroughs in , and the fastest growing industrialized nations in brought down rates the world. We have the third largest and led to longer life spans. The population of all nations, preceded only by mechanization of agriculture and and . At 5% per year, the U.S. also improvements in led to has the highest teen pregnancy rate of any even greater increases in food production and modern industrialized . availability. Human numbers began doubling at an unprecedented pace. With a current annual growth rate of 1.14%, Rates of Growth Past is projected to double in just A graph of human population before the 61 years. Our doubling times will be realized agricultural revolution would likely have if and only if growth rates remain constant. suggested a wave, reflecting growth in times Doubling time is the amount of time it takes of plenty and decline in times of want. Graphs a population to double its number. Today, the world's is almost three times its 1 death rate. The closer these two rates are, the What is ? slower population growth will be. Most people equate overpopulation with (ZPG) is the crowding, but, in fact, density is largely demographic term for the state of equilibrium irrelevant to questions of overpopulation. reached when birth and death rates are the What is relevant is . An area same. Birth rate is the number of live births is overpopulated when its long-term carrying per thousand people. Death rate is the capacity is being degraded by its current number of people that die per thousand human occupants. people. Momentum is also a factor in population growth. Some , like the Degree of Impact U.S., are growing even though the average The impact of any human group on its woman has just two children. In such cases, a environment has to do with three equally population can still take 60-70 years to important factors. The first is the number of stabilize, and will do so only when the people. The second factor encompasses the percentage of elderly people is equal to the ways in which we manufacture goods, design percentage at child-bearing age. communities and use technology. The third is the actual amount of resources consumed by Density vs. Consumption, Space vs. each person. Carrying Capacity "The entire world's population could fit into Unfortunately, the rate at which industrialized the state of Texas." This statement is nations consume resources makes their frequently cited by people who don't populations' effect on the planet vastly greater understand the difference between not than that of developing countries. currently occupied by humans and the amount and type of land required to support human Population growth and rapid consumption of life. People are only able to live in densely resources are equal parts in the problem of populated areas if enough space elsewhere is environmental degradation. For example, the left much less densely populated. For United States could reduce our consumption instance, must be available to of resources and generation of by grow the food for people living in and half today. But if we did so without slowing . Trees and other plants must be left to our growth rate, the difference would be made produce the we all need. up in 72 years, when our population is expected to double. An area's carrying capacity is the number of a given species that area can support without The Environment and the Importance of impairing its ability to continue supporting that population. The land within Texas could An will be more robust with a not provide enough food, or to greater the variety of species within it. It is meet the needs of 6.6 billion people. It could the biodiversity, the variety of life, on not accommodate all the generated by that makes our survival possible. Biodiversity so many either. Because that area could not provides crucial "ecosystem services", such come close to sustaining all of the world's as, clean water, breathable atmosphere and people, the fact that we could all physically fit natural climate control, upon which all into that space is virtually meaningless. species depend. The extermination of plant populations changes climates locally and has severe regional effects through disturbance of

2 the water cycle. Food, medicine and shelter industrialization, economic development, are all derived from the abundant organic availability of quality medical care, the resources of the Earth. In fact, more than 50% educational level of the population and the of the prescription drugs dispensed worldwide status of women. are derived from wild plant species. The Industrial Revolution in Western Europe We demand more space and resources from and North America improved living the Earth as human numbers grow. Taking conditions through advances in medicine, more for people means leaving less for other sanitation and nutrition. These changes led to species. Loss of habitat results in the declines in death rates, especially among of countless numbers of plant and infants and small children. However, birth animal species every year. Currently, 20-75 rates remained high and soon the population plant and animal species are lost every day as swelled. a result of . It is estimated that by 2015 some 6-14% of all species will have As these regions gradually moved away from gone extinct. an agricultural way of life and became more urbanized, large families became less Doubling Time practical and more expensive. Machinery was The world's current population is estimated at used more frequently to plant and 6.6 billion, with an annual growth rate of 1.14 food reducing the need for children as farm percent. 1.14 percent may not sound like a workers. Urban families bought food instead large number, but, at this rate, almost 77 of harvesting it. Over the course of the 19th million people will be added to the population and early 20th centuries, birth rates dropped this year. dramatically in these areas. Another way to see the impact of growth rates Developing areas, such as , Latin is to consider the doubling time of a America and parts of are still primarily population. Doubling time for a population agriculturally based. Therefore, incentives for can be calculated by dividing 70 by the having larger families still exist. Technology growth rate. For example, 70 divided by 1.14 imported from industrialized countries not is 61.4. This means that if present growth only improved living conditions but caused rates continue, our world population would death rates to plunge dramatically. As a result, double in about 61 years. Twice as many these populations are growing rapidly. people would need twice as much food, water, roads, houses, schools, churches, sanitation In many countries, the low status of women is facilities, etc. Many ecologists worry that our another contributing factor to higher birth planet can't support another doubling of rates. Women are often denied educational population. and employment opportunities and have few alternatives to their childbearing roles. Many Why are developing countries experiencing people wish to limit their family size but lack rapid population growth while developed access to and countries are growing slowly or not at all? services. Both developed and developing countries have experienced significant declines in their Are areas of high bad? death rates and prolonged life expectancies. No. To the contrary, urban areas hold hope for Developing nations continue to have higher human development and protection of natural birth rates than developed countries. A resources because they can efficiently support country's birth rate is strongly linked to large numbers of people thus limiting their 3 impact on the . One of the U.S. consumption patterns are dramatically reasons that cities are growing rapidly is different from those in the developing world. because they offer more economic and social Although Americans comprise only 5 percent benefits than do rural areas. of the world's population, we use 25 percent This contrasts to poorly planned areas of of its resources and produce more trash and urban and suburban sprawl, which are fast- pollution than citizens of most other nations. growing, low-density developments typically The average American's energy use is found outside major urban areas. When equivalent to the consumption of 2.5 sprawl attacks, it can result in a loss of green Japanese, 6.6 Mexicans, 16.5 Chinese, 33 space, increased dependence on automobiles, Indians or 121 Bangladeshis. Even moderate , and a wasteful population growth in the U.S. spells problems use of land resources. for the global environment. When is the population of the United States Don't AIDS, wars, and disease cancel out expected to stabilize? population growth? Our population will stabilize only when the No. Our ability to reproduce is one of our number of births plus immigrants (people species' greatest strengths. The wars of the coming into the country) equals the number of have accounted for the deaths of deaths plus emigrants (people leaving the nearly 200 million people. Yet, in that time, country). It is not clear when, or even if, human population has increased by 4 billion, stabilization will occur. The United States is 20 times more than those killed in wars. the third most populous country in the world Similarly, other tragedies throughout history and is growing by more than 3 million people have accounted for only a small percentage of each year. According to modest projections by deaths worldwide. Even AIDS, which affects the U.S. Bureau of the , the U.S. millions worldwide, appears only to be population could grow by 130 million altering population projections in Africa, Americans by 2050. south of the Saharan Desert. Some people are surprised to find out that our There has only been one time in human country's population will not immediately history when our population growth was stabilize once the total rate reaches a slowed significantly: In the 14th Century, replacement level of 2.1 (which is the growth bubonic plague, along with wars, killed an rate for the U.S.). Due to "population estimated one-third of the global population. momentum," our nation's population would Within 100 years, population was back to pre- continue to grow for another 60 to 70 years. plague levels. This is because growing nations have many fewer people near the end of their lives than Why should the United States be concerned they have people at reproductive age. about its own growth? Populations would stabilize after a couple If we were only concerned about sheer generations once those age groups have had numbers of people added to the population, time to balance out. then indeed, growth in countries such as India would be far more alarming than growth in Women of the World the United States. But if we consider the “Women hold up half the sky,” reads an old impact of each person's lifestyle on the Chinese saying. Indeed, women have world's resources, then we reach an entirely traditionally been the world’s farmers, child different conclusion. bearers and caretakers of young and old. 4 Women are the backbone of families and instead? Suddenly Shanghai might start . Despite their contributions to looking more like . And if half humanity, women continue to suffer from the people in Los Angeles could bike instead gender discrimination in much of the world. of drive? That would save a lot of gas and cut Being born female in much of the world down on pollution that to , means a lifetime as a second-class citizen. “bad” and possible global warming. Women are denied most of the opportunities available to males in the areas of health, If we don’t take care of our resources, we education, employment and legal rights. This can’t take care of ourselves. In Barbados, the second-class citizenship hurts the well being beaches are kept spotlessly clean because the of women. It is also a major contributor to island’s economy depends on tourists visiting rapid rates of population growth in the world. the pristine sands. And in Los Angeles a family could replace their front lawn with Lifestyle Choices: Getting the Story on desert plants in order to save water. If people Resource Use in developing nations had affordable forms of It really wouldn’t matter how many people cooking fuel available, like a solar powered lived on our planet if each of us didn’t need stove that is becoming popular in parts of resources to survive and to thrive. But since Africa, they would save time and help we do, we can’t ignore the resource preserve local forests. connection. For many people in the world, getting the resources they need takes up much Population and resource use impacts animals of their day. Some have to find wood for and plants as well as people. As human energy. A simple neighborhood pump will populations continue to grow and consume save others hours of labor each day collecting more resources, we are losing forests and water. Many people don’t have the resources driving other species towards extinction. they need even in our own country, When we start to look at population and Some interesting facts appear when you begin resources together we see that our world is to look at how the resources of our world are interconnected. Everything from the way we distributed. Most population growth in the get to school, to the water we use for washing world (over 98%) takes place in developing our faces, to what we choose to eat is all countries of Asia, Africa and . connected with decisions made by the other In industrialized countries such as the United six billion people who share our planet. States, , or Italy, population growth is much slower, even with immigration. In some places the population is stable or declining. So surely a huge wealthy nation like ours doesn’t need to worry? But wait a minute! Some argue that people in the U.S. and other industrialized countries have a much greater impact on the world’s environment because of our high resources use. In other words, people here use more stuff and throw away more trash than in almost any other place in the world! What if all of the people biking to school each day in Shanghai drove a

5 Write all answers in your notebook!

Population Questions

1. What is a “J curve”?

2. In general, what does the “J curve” indicate is happening to living conditions throughout the world? Explain your answer.

3. What does the development of technology have to do with population growth rates?

4. What is zero population growth?

5. What does the term doubling time refer to?

6. Why are developing countries experiencing rapid population growth while developed countries are growing slowly or not at all?

7.Is over-crowded (hint: has it exceeded its carry capacity)? Explain.

8. Why should you be concerned with growth of population in the United States when we only account for ~5% of the world’s population?

Matching doubling time death rate biodiversity arable land

J-Curve birth rate emigrants immigrants carrying capacity overpopulated zero population growth

9.the amount of time it takes a population to double its number 10. a population curve that starts out low and skyrockets upwards 11. the number of live births per thousand people 12. the number of people that die per thousand people 13.land that can be used for growing crops 14. the number of a given species that area can support without impairing its ability to continue supporting that population 15.When the condition of any 's numbers exceed the carrying capacity in a given area 16.variation of life forms in a given community

6 17. the demographic term for the state of equilibrium reached when birth and death rates are the same 18. people coming into a country 19. people leaving a country

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