BISC 121 - Global Population Changing - Midterm 4

What population policies did Singapore implement in the 1970s–80s?

Singapore first discouraged more than two children, then reversed course and encouraged larger families.

Why do governments try to keep population size in a “Goldilocks zone”?

To maintain economic stability and plan for infrastructure, taxes, development goals, and emissions targets.

Who has historically produced the most influential population projections?

The United Nations Population Division.

How do UN projections differ from newer forecasts?

The UN predicts a rise to 10.9 billion by 2100; rival groups predict earlier, lower peaks around 9.7 billion before decline.

Why is accurate current population data essential for projections?

It provides a baseline for forecasting and guides present-day policies such as vaccine allocation and school planning.

How has COVID-19 affected population data collection?

It delayed censuses and altered short-term estimates of birth rates and life expectancy.

What are the two key components needed to calculate current population?

Counts of births and deaths, and migration data.

Why are short-term population projections considered reliable?

Most people who will be alive in the next few decades have already been born.

What major demographic variable most affects population size?

The fertility rate.

What is the fertility replacement level?

2.1 births per woman.

How has Singapore’s fertility rate changed since the 1970s?

It fell from about 3.04 to around 1.23, well below replacement level.

How does economic development affect fertility rates?

As education rises and contraception becomes available, fertility typically declines.

How did COVID-19 impact fertility in high-income countries?

Births fell sharply due to economic and social uncertainty.

What did data show about birth declines during late 2020 and early 2021?

Births dropped 5–9%, with Spain experiencing declines near 20%.

What is expected to happen to birth rates after the pandemic?

A rebound is likely in some countries as conditions stabilize.

How does the UN project long-term fertility changes?

By modeling countries through phases of fertility transition using 100,000 simulated pathways.

How does IIASA produce its projections?

By surveying experts across multiple fields to estimate future fertility for each country.

How does IHME model future population differently?

It uses completed cohort fertility at age 50 and ties forecasts to education levels and contraceptive access.

Why is the IHME model controversial?

Critics say it contains implausible assumptions and internal inconsistencies.

What is an example of a disputed IHME prediction?

Iraq allegedly reaching one of the world’s highest female life expectancies.

Why do some demographers warn that projections can shape policy?

Governments may react to declining fertility predictions with restrictive reproductive policies.

Why do population forecasts differ so widely?

Models make different assumptions about how quickly fertility will fall with development.

How accurate have UN population projections been historically?

They have predicted past global totals within a few percent.

What new methods are improving population counts in unstable regions?

Techniques using mobile-phone data and satellite-based mapping of buildings.

How can mobile-phone data help estimate population?

Call density around cell towers can signal population movement and concentration.

How can satellites aid in population measurement?

By mapping structures and settlement patterns to estimate the number of residents.

Why are traditional censuses still important?

They collect detailed demographic data that alternative methods cannot replace.

What is the biggest challenge for countries lacking recent censuses?

Population estimates can vary wildly and be unreliable.

What overall question drives government interest in demography?

Knowing how their population will change in the next few decades for economic planning.