The Human Population and Its Impact

Ch. 6, part 1

Jot down the number of people in the world now

Our Growth Continues

Only in the last 200 years has it been going up so sharply

Question 1, with your pet buddy:

Hypothesize as to WHY our population growth continues to be so high

Why?3 main reasons

We’ve gotten better at living in more places

Agriculture meant we could feed more people

Better sanitation, medicines, and vaccines keeps disease under control

The results of all this

Death rate drops significantly

Birthrate has actually slowed - but it is not enough to counter the death rate

Some numbersThe global population is growing at ~ 1.2%/year

82 million people added to the population in 2008

Every second 5 people are born, 2 people die - a net gain of 3 people

That’s over 260,000 people per day

Where are all these people?We are not evenly spread out

Of the 82 million added in 20081.2 million added in the developed nations

80.8 million added in the developing nations

Developed vs. Developing Nations

DevelopedUSCanadaJapanAustraliaItalyEnglandFrance

Highly industrializedHigh GDP

DevelopingMost of AfricaMost of AsiaMost of Latin AmericaChinaIndiaBrazilTurkeyThailandMexico

Highly agriculturalLow GDP

What is the What is the difference difference between these between these two groups?two groups?

Developing nations

97% of the population growth from now to 2050 will occur in these countries

More than 1/2 the people in the world live in extreme poverty (less than $2/day; 17% of those on less than $1/day)

So how big are we going to get?

?

Projections are 8-11 billion by 2050

Question 2 with your holiday buddy: Vote!

Should the United States adopt a population control policy? Defend your position.

How many people can the Earth support?

Low estimates - 2 billion

High estimates - 30 billion

Is this even the right question to ask?

Another way of looking at it

Many analysts think we should be asking:

What is the optimum sustainable population based on a cultural carrying capacity

The optimum level at which most people can live in comfort and freedom without sacrificing that for future generations

Some basicsHigh births -- low deaths = high growth

Low births -- high deaths = decline

Equal births and deaths = stable population

3 rates control human population size

Birth rate

Death rate

Migration rate

We calculate the population change by subtracting those who leave (death, emigrants) from those who arrive (births, immigrants)

RatesWe don’t use raw numbers usually, we use RATES

Birth rate - the number of births per 1000 per year

Death rate - the number of death per 1000 per year

Who has the most people?Number 1: China at 1.5 billion

Number 2: India at 1.1 billion

Number 3: USA at 300 million

Number 4: Indonesia at 240 million

Number 5: Pakistan at 173 million

Together they have 36% of the people

Women are having fewer babies

Fertility rate - the number of children born to a woman during her lifetime

2 types1. Replacement level fertility rate - the

number of children a couple must have to replace themselves

1. 2.1 in developed nations

2. 2.5 in developing

2 types

2. Total fertility rate - the average number of children born to women in a population during their reproductive years

This has been going downDeveloped nations

1950 - 2.52008 - 1.6

Developing nations1950 - 6.52008 - 2.8

Question 3

WHY 2. WHY 2. something? Why something? Why not just 2?not just 2?

10 Factors that affect the birth rate

1. Children in the work force

1. Developing nations tend to have more children in the work force

More or less kids?More or less kids?

10 Factors that affect the birth rate2. The cost of raising and

educating children- birth rate lower in developed countries where it is much more expensive to raise kids (they don’t work for the family usually)

- costs about $290,000 to raise a kid to 18 years old

More or less kids?More or less kids?

10 Factors that affect the birth rate3. Private and public

pension systems (or lack thereof)

Pensions reduce the need for children to care for adults in their old age

More or less kids?More or less kids?

10 Factors that affect the birth rate

4. Urbanization - urban areas have more family planning clinics --> less kids

rural families need kids to help raise crops/livestock

More or less kids?More or less kids?

10 Factors that affect the birth rate

5. Education for women

fertility rate lower when women are educated

marriage is delayed also

More or less kids?More or less kids?

10 Factors that affect the birth rate6. Infant Mortality Rate

- the number of children per 1000 births who die before age 1

More or less kids?More or less kids?

10 Factors that affect the birth rate7. Age at marriage

More or less kids?More or less kids?

10 Factors that affect the birth rate8. Ability to have abortions

each year ~ 190 million pregnancies

~ 46 million abortions

(about half illegal) More or less kids?More or less kids?

10 Factors that affect the birth rate9. Availability of birth

control methods

More or less kids?More or less kids?

10 Factors that affect the birth rate10. Religious beliefs,

traditions, culture More or less kids?More or less kids?

Question 4

Is it rational for a poor couple in a developing country such as India to have 4 or 5 children?

Explain your thinking.

Put this number next to your name

Jot down the number of people in the world now

How many people were added during our lesson?