In what ways has population growth shaped the movement of people and the human impact on the environment quizlet?

exponential growth:
-the growth of any quantity at a fixed percentage per unit of time

-Growth in which some quantity, such as population size, increases at a constant rate per unit of time.

Examples:
- The growth sequence 2, 4, 8, 16, 32, 64, and so on, which increases by 100% at each interval. When the increase in quantity over time is plotted, this type of growth yields a curve shaped like the letter J.

-a population can grow at 2% per year, a rate that will double its size every 35 years.

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Exponential population growth starts out slowly, but eventually, the population's size increases rapidly. This is because, even if the percentage of growth remains constant, at 2%, the number of people added every year gets larger because it is 2% of a larger and larger total. So the population grows by a much larger amount in each unit of time, and eventually it explodes

Two other important factors in human population growth are related to the death factor of the equation

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life expectancy, the average number of years a person in a population can expect to live.

It is calculated by statisticians who consider a host of factors such as diseases present in the population, occupations, accident rates, and other health hazards. The higher the life expectancy, the more likely a population is to remain stable or to grow.

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Infant mortality rate, or the number of babies, out of every 1,000 born, who die in their first year of life.

Because infant mortality is related to a country's general level of health care and nutrition, it is viewed as one of the best measures of a society's quality of life. If this number is high, it can slow a population's rate of growth. The lower this rate is, the more likely the population is to remain stable or to grow.

However, renewable resources such as forests and the fresh water in streams can be replenished as long as we do not use or pollute them faster than natural processes can renew them. When we do misuse them in these ways, they can become degraded and possibly depleted

examples
- much of the water we use to irrigate crops and to supply cities, factories, and homes comes from underground deposits of water, called groundwater, stored in formations called aquifers. Most aquifers are renewed by rain that percolates down through the soil. However, if we drill wells and remove water from this type of aquifer faster than it is replenished, the available supply of water can shrink. In this way, we can deplete the aquifer.

-topsoil. Wherever farmers grow crops year after year to feed more mouths without adding nutrients to replace those that are taken up by their crops, those topsoil nutrients provided by nature become exhausted. Then, to replace nature's free soil nutrients, farmers are forced to use costly fertilizers, which can cause water pollution.

-mineral resources. As populations grow and as resource use per person increases, several countries have exhausted their stocks of important minerals such as copper and gold, and must rely on other countries to supply these resources at great cost. Today, the United States imports all or nearly all of its supplies of 25 key nonrenewable mineral resources.

-overexploitation of many wild species. Numerous ocean fish species have been overfished to the point where their populations are depleted. Rare and endangered plants and animals are being collected, captured, or killed for use as food or as part of the global trade (illegal as well as legal) in ornamental plants, exotic pets, and animal hides, horns, and other body parts. This is a growing factor in the sharply rising rate of biodiversity loss.
((This scarlet macaw is found in several of the tropical rain forests of Central and South America. These birds are endangered due to loss of habitat and because they are captured and sold as pets, often illegally.))

A growing population and growing per capita ecological footprints can also lead to other forms of environmental degradation and depletion.

-One example is deforestation, the extensive cutting and burning of forests to make way for crops, grazing land, settlement, and the expansion of cities.
Often, the result is erosion of a forest's topsoil to the point where the forest cannot grow back.
Clearing a forest or grassland and replacing it with roads, parking lots, houses, and other buildings have the same effect.

-The processes of mining and producing mineral resources also degrade vast areas of land, pollute air and water, and destroy wildlife habitat.

- the rising global average level of carbon dioxide (CO2) in the atmosphere. This has resulted primarily from the large-scale burning of fossil fuels and the removal of forests that absorb CO2 from the atmosphere, as both the human population and resource use per person have grown. Higher atmospheric levels of CO2 and other greenhouse gases are adding to the problem of atmospheric warming, which is projected to disrupt the earth's climate during this century.

-In some cases, we can deplete a renewable resource to the point where it cannot recover.

Overpopulation impacts
The results of population size being the biggest factor in a country's total environmental impact, common in less-developed countries where environmental degradation, such as deforestation and depletion of topsoil, often results from a growing number of poor people trying to survive by using these resources; while average resource use per person in these countries is low, the total resource use is high because of the large and growing population.

overconsumption impacts
In more-developed countries, the environmental degradation that typically results when affluence is the biggest factor in a country's total environmental impact. In these countries, the high rate of resource use per person leads to high levels of waste, pollution, and resource depletion and degradation.

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Some forms of technology have a high environmental impact because they increase the T factor.

Examples are gas-guzzling motor vehicles and farm machinery, polluting factories and power plants that burn coal.

Other technologies can lower an environmental impact by decreasing the T factor.

Examples of technologies that prevent or reduce pollution are air pollution control systems, solar cells, and wind turbines

There is growing concern that as our ecological footprints grow and spread across the earth's surface, we are likely to reach several ecological tipping points and overwhelm the carrying capacity of more and more of the planet's natural systems.

The exact size of the earth's carrying capacity for the human population is a subject of debate. The estimates of experts range from about 2 billion to as many as 50 billion people. The high-end estimates carry the assumption that humans will develop technologies that will allow more and more people to live on the planet at higher levels of resource use without increasing our overall environmental impact.

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Such technological optimism could be dangerous if we continue to expand the population and its resource use per person, and fail to develop environmentally beneficial technologies to offset our resulting harmful environmental impacts.

They suggest that, given the environmental problems we face today with a population of 7 billion, we may be nearing the earth's carrying capacity.

Some argue that we already have exceeded it and will eventually face a dieback of the human population imposed by natural processes that have always controlled the populations of other species that exceeded the carrying capacities of their environment.

Other experts, including some economists, believe that continued economic growth can provide enough resources for tens of billions of people without serious environmental harm.
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two serious consequences if we fail to slow and eventually halt human population growth by sharply lowering birth rates, and fail to find ways to reduce the harmful environmental impacts of resource consumption.

1. In some areas, health and environmental conditions will deteriorate, and death rates will rise. This is already happening in parts of Africa and southern Asia, partly because of a combination of eroding soils, lower food production, water shortages, severe poverty, and conflicts over control of vital resources.

2. A growing population of consumers will expand the already large ecological footprints in more-developed countries such as the United States and in rapidly developing countries, such as China and India. This will likely lead to spreading resource depletion and environmental degradation.

In most countries, women have fewer rights and educational and economic opportunities than men have. Yet within their families, women provide more unpaid health care, globally, than that provided by all of the world's organized health services.

In rural areas of Asia, Africa, and Latin America, women and girls do well over half of the daily work devoted to growing food, finding and hauling water, and gathering and carrying firewood.

Women account for about two-thirds of all the hours of work performed every day throughout the world but receive only a tenth of the world's income and own less than 2% of its land.

In many societies, sons are valued more than daughters, and parents often make their school-age daughters work at home instead of sending them to school. As a result, about 900 million girls—almost 3 times the entire U.S. population—do not attend elementary school. And almost 2 of every 3 illiterate adults and 7 of every 10 people in the world who suffer from poverty are women.

Poverty is the set of conditions that people endure when they are not able to meet their basic needs.

Every day, the world's desperately poor people struggle to get enough water, firewood, food, and money to survive. As a result, some of these people unintentionally degrade renewable forests, grasslands, soil, and wildlife.

1.UN Millennium Development Goals—for sharply reducing poverty and hunger, improving health care, achieving primary education for everyone, empowering women, and moving toward environmental sustainability by 2015.

2.Businesses and governments can help to cut poverty and reduce population growth by providing funds and other assistance toward achieving the UN Millennium Development Goals. Governments and businesses could fund solar energy technology to provide electricity for many of these villages, and they could also help poor people to work themselves out of poverty by providing small loans.

3. More-developed countries agreed in 1979 to devote 0.7% of their annual national income toward achieving these goals. But the average amount donated in most years has been 0.25% of national income. The United States, the world's richest nation, has been donating only 0.16% of its national income.

One very promising way to help poor people who want to work their way out of poverty is to provide them with small loans for purposes such as starting a small business or buying seeds and fertilizer for growing food crops. Most of the world's poor people do not have a credit record or the means to qualify for conventional loans.

In 1983, economist Muhammad Yunus (Figure 2.A) started the Grameen (Village) Bank in Bangladesh, a country with a high poverty rate and a rapidly growing population. Since then, the bank has provided a total of $7.4 billion in microloans of $100 to $1,000 at very low interest rates to 7.6 million impoverished people (97% of them women) who cannot qualify for loans at traditional banks.

Almost all of these loans have been used by women to plant crops, to start small businesses, or to buy livestock, bicycles for transportation, or small irrigation pumps.

To promote loan repayment, the bank puts borrowers into groups of five. If a group member fails to make a weekly payment, other members have to make it instead. As a result, the bank has made a solid profit and the average repayment rate on its microloans has been 95% or higher—much higher than the average repayment rate for loans by conventional banks.

About half of the bank's microborrowers have moved above the poverty line and improved their lives within 5 years. Between 1975 and 2005, this innovative approach, along with the hard work of the people receiving the microloans, helped to reduce the poverty rate in Bangladesh from 74% to 40%.

In addition, birth rates are generally lower among most of the borrowers.

The government provides contraceptives, sterilizations, and abortions for married couples. In addition, married couples pledging to have no more than one child receive a number of benefits including better housing, more food, free health care, salary bonuses, and preferential job opportunities for their child.
Many (but not all) couples who break their pledge lose these benefits.

The one-child policy has presented other problems. Because of a strong preference for male children, China has a rapidly growing bride shortage. Young girls in some rural areas of China are being kidnapped and sold in other parts of the country as brides for single men. In some cases, pregnant Chinese women get abortions if their ultrasound scans show that their fetus is female.

Also, because there are fewer children, the average age of China's population is increasing rapidly. This shift in age structure means that there will be fewer children and grandchildren to care for the growing number of older people, and there will be fewer workers to support the economy. These factors may lead to some relaxation of the government's one-child population policy.

There are two major reasons.

First, each of us depends on the earth's life-support systems for food, shelter, clean water and air, energy, and other vital resources such as wood, iron, and aluminum. Adding more people to the population increases the need for these natural resources as well as natural services such as chemical cycling and renewal of topsoil.
Also, average income per person is rising in many countries, and most of the world's more affluent consumers tend to use more of the earth's natural resources and services. As a result, average per-person, or per capita, natural resource use is very high in wealthy countries such as the United States and much lower in poorer countries such as India .

The second major reason for caring about population growth is the strong and growing scientific evidence that we are degrading our life-support system with our rapidly growing ecological footprints (see Module 1, Figure 1.23). Each newcomer adds to this planetary stress, especially in areas of the world where people are using a lot of resources.
While our ecological footprints are growing larger, we are not meeting the basic needs for many of the people alive today.

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