Population growth Notes

What Is Population Growth Driven By?

1. At any scale (a city, a country, or the world), three processes drive this change:
   1. Births (adding people)
   2. Deaths (removing people)
   3. Migration (moving people into or out of a place)
2. Although the world population grew slowly for most of human history, it has risen rapidly in recent centuries and was about 7.5 billion at the time of the source text.
3. Crucially, growth is uneven: different regions and countries experience different rates and different consequences.

How Do Population Measures Let You Describe And Compare Places?

1. To understand why populations grow at different speeds, geographers and social scientists use a set of standard measures.
2. These indicators help describe population change and support predictions and planning.

Why Birth Rate and TFR aren't the same

1. A birth rate counts births against the entire population, including many people who can't have children like men, children, and older adults.
2. This makes it useful for quick, headline comparisons, but less helpful for understanding how many children families actually have.
3. Total fertility rate (TFR) on the other hand looks only at women of child-bearing age and estimates the average number of children per woman over her lifetime.
4. Because it focuses on those who can give birth, TFR gives a clearer picture of family size and is a better indicator of long-term population change.

How Is Natural Increase Calculated?

1. Natural increase begins as a difference "per 1,000 people."
2. It's often converted into a percentage growth rate so it can be compared more easily between places and over time.

How Do Development Patterns Help Explain Differences In Growth Rates?

1. Population growth is not equally distributed.
2. Many higher-income countries (often described as more economically developed) have low population growth because both birth rates and death rates are low.
3. Death rates tend to be low when health care, education, sanitation, and nutrition are strong.
4. Birth rates tend to be lower when people have:
   1. Reliable access to contraception
   2. Lower infant mortality (parents feel more confident their children will survive)
   3. Higher female education and improved gender equality, which often links to later marriage and later first births

What Are Population Pyramids?

1. A population pyramid is a bar chart that displays the age and sex structure of a population.
2. Typically:
   1. The vertical axis shows age groups
   2. The left side shows males, the right side shows females
   3. The width shows the size of each age group
3. Age structure matters because it strongly influences:
   1. Future births (how many people are entering childbearing ages)
   2. Demand for schools, jobs, and housing
   3. Health care and pension costs
   4. The dependency ratio

Reading a pyramid for growth clues

1. An expansive pyramid (wide base) usually suggests high birth rates and a young population.
2. Even if birth rates start to fall, a very large number of young people can create continued growth because many will soon become parents.
3. This is often called population momentum.
4. A constrictive pyramid (narrow base, wider middle/top) suggests low birth rates and an aging population.
5. Growth slows, and the total population may eventually shrink unless offset by net immigration.

How Do Governments Use Population Policies To Manage Growth?

1. Because population change affects schooling, employment, housing, and health services, governments sometimes introduce population policies to influence fertility.
2. Pro-natalist policies aim to increase births (for example, child benefits, parental leave, subsidized childcare).
3. Anti-natalist policies aim to decrease births (for example, incentives for smaller families, later marriage campaigns, or limits on family size).

What Does Rapid Growth Have To Do With Urbanization And Megacities?

1. Population growth and migration can accelerate urbanization, the growth of the urban population.
2. One major outcome is the development of megacities, defined as cities with more than 10 million people.
3. In the early 1970s only Tokyo and New York were megacities (with Mexico City joining in 1975).
4. By 2017 there were 37 megacities, and the UN projects 41 by 2030, with many of the largest in Asia.

Consequences for individuals and societies

Megacity growth can bring opportunities and pressures at the same time.

1. Potential benefits include:
   1. More jobs and higher incomes for some migrants
   2. Better access to specialized education and health care
   3. Cultural diversity and innovation
2. Potential challenges include:
   1. Housing shortages and the growth of informal settlements
   2. Congestion, pollution, and strain on water and energy supplies
   3. Inequality, with sharp contrasts between wealthy and poor neighborhoods