1. World Population: Growth & Trends

2. Demographic Questions
Why is population growth so central to environmental problems?
What is the current population? What will it be in 2050?
What factors affect population growth rates?
How do growth rate compare in developed vs. developing countries?
What is a "demographic transition? What are its stages?
Interpreting Population Pyramids.
Understanding modern demographic trends.

3. Developed Country Developing Country
Low birth rate
Most of the people are over 15 years of age
Long life expectancy
Low infant mortality rate
Most people live in urban areas (cities)
High per capita Gross Domestic Product
High literacy rate
Highly industrialized
People make a living in secondary or tertiary economic activities
High birth rate
Most of the people are less than 15 years of age
Low life expectancy
High infant mortality rate
Most people live in rural areas (country side)
Low per capita Gross Domestic Product
Low literacy rate
Little industry
People make a living in primary economic activities.

4. World Population: 7.6 billion
As of Dec, 2017
(Super)exponential growth

5. Exponential Growth J curve
Population growth after 1800’s ranged %!
Super-exponential growth
Post-1960 was first time EVER that population doubled within a generation

6. Population by 2050: 9 billion

7. Factors affecting Growth Rate
Growth rate = Birth Rate - Death Rate
1.3% = 2.2% - 0.9% (early 2000s)
1.1% = 1.9% - 0.8% (today)
Of these the Birth Rate is the most important contributor, specifically the Fertility Rate (#children/woman)
2.42 children/women (World)
1.6 children/woman (Canada)
Why? Because death rates have stabilized...

8. Factors affecting Birth Rate
Global BR = 1.9% or 19/1000
Lessons on population control from Thailand, South Korea, Japan, India, and China:
Invest in Family Planning
Reduce poverty
Elevate the status of women

9. Factors affecting Death Rate
Global DR = 0.8% (higher in LDC vs MDC)
Low death rates due to:
medical treatments,
better food supplies and nutrition,
improvements in sanitation, and
access to clean water
Lower DR is the main reason for the global population increase

10. INFANT MORTALITY When infant mortality rates rise….
Population actually increases
Why?

11. ANSWER
For many parents in the developing world their only sense of old age security is their offspring.
If the death rates are high when their babies are born, they must have more children to ensure the survival of a son to care for them

12. Population Projections
Current ~7.6 billion (and rising), growth rate: 1.1% (and falling…).
Projected 2050 population: Approximately 9 billion

13. Calculating Doubling Times
The “Rule of 70”:
Doubling time = 70/percentage growth rate
Example:
Current growth rate is 1.1%, so doubling time is 70/1.1 = 64 years (ca. 2080).
Projected pop near 2080 would be ~14 to 15 billion if the growth rate stays the same.
But this won’t be the case… why?

14. Carrying Capacity
At the heart of this issue is the concept of Carrying Capacity (K)
the maximum number of individuals that the environmental resources of a given region can support.
Population growth and Carrying Capacity co-evolve.
Factors: Technology, social, political, economic institutions, physical & ecological environment.

15. Where people live

16. Population growth rates