Ppt Demography

7/30/2019 Ppt Demography

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Demography

The increase of the world population*

Population histograms : ranking/country**

Population curves between Europe and Africa**

Resources

* http://www.ined.fr/en/everything_about_population/animations/world_population/

** http://www.ined.fr/en/everything_about_population/population_atlas/


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In 1999, there were 6 billion people living on Earth, and by 2011 or 2012, the

population will reach 7 billion.

Why is the world population increasing so fast ?

And what will happen in the future ?

Introduction

The increase of the world population

Population growth

today

World population

history

The demographic

transition

The future world population :

explosion, implosion, or

equilibrium ?

Conclusion

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Population growth

today


Every second, on average, four babies are born.

Every second, on average, two people die.

Every second, on average, the population increased by two people.

Two more people per second means 200 000 more people per day, and 75

million more people per year. In other words, the world population6,5 billion

in 2005is growing by 1,2 percent each year.

At this 1,2 % annual growth rate, the population doubles evrey 60 years. If the

number of people on Earth carried on increasing at this speed, the 6,5 billion in

2005 would become 13 billion in 2065, 26 billion in 2125 ans so on. But the

population does not grow at the same speed indefinitely. On the contrary, the

United Nations predict that the world population will level off at around 9billion people before the end of the century.

Why is that ?

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World population

history


Billions

of inhabitants

World population increase in the last two thousand years

Throughout most of human history, the number of people on Earth could be counted in just hundreds of thousands or in

millions, and the population increased very slowly. Two thousand yeras ago, there were around 250 million people in

the world, and by the end of the 18th century the total had reached one billion.

At around that time, the population started growing much faster. From one billion in 1800, it rose to two billion in

1927, 3 billion in 1960, 4 billion in 1974, 5 billion in 1987 and 6 billion in 1999.

Whe should reach 7 billion by around 2011 or 2012, and growth will not stop there. So what will happen next ?

The United Nations are forecasting that the world population will level off at a mere 9 billion by around 2050.

How did they reach this figure ?

And looking back in history, why did the population grow so slowly up to the eighteenth century ? Why did it start

rising so fast from then on ?

0 500 1000 1500 2000 years

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The demographic

transition


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equilibrium ?


Billions

of inhabitants

World population projections to 2300 : scenario 1

1950 2000 2050 2100 2150 2200 2250 2300 years

In the demographic transition model, fertility stabilizes at the remplacement level two children per

womanwhen mortality is low.The United Nations have imagined a scenario in which future families each have exactly two children

on average, in which case the world population would level off after reaching 9 billion.

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equilibrium ?

Billions

of inhabitants

1950 2000 2050 2100 2150 2200 2250 2300 years


But in many countries where the demographic transition is complete, average fertility is well below 2

children per woman. For example, it was 1,5 in the countries of the European Union in 2005, and 1,3 inJapan.

If very small families became a world-wide model over the long term, the world population would peak at 9

billion then start declining until human beings eventually died out altogether.

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equilibrium ?

Billions

of inhabitants

1950 2000 2050 2100 2150 2200 2250 2300 years


Fertility may also start increasing again in the countries where it is currently very low,

stabilizing at 2,3 children worlwide. This would result in continuous growthup to 37billion in 2300and here agaiun the ultimate disappearnce of the human race, this time due

to overpopulation.

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equilibrium ?

Billions

of inhabitants

1950 2000 2050 2100 2150 2200 2250 2300 years


Under the so-called contant fertility scenario, in which fertility remains at its current level for the

next three centuries, the population would reach 134 000 billion in the year 2300 !

But this scenario is unrealistic, since fertility is decreasing throughout the world. It simply shows us

how continuous growth leads to explosion within a very short time.

These catastrophic scenarios, resulting in the extinction of the human race through implosion or

explosion, are not the only alternatives. We need to imagine a return to equilibrium over the long term.

The medium scenarios based on assumption that achieve a long-term balance, such as fertility of

exactly two children per woman for example.

It is no more realistic than the high or low scenarios, but simply shows what path needs to be followed

if we to survive beyond the next few centuries.

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In 1999, Humankind is starting to control its population growth. But to ensure

a decent standard of living for 9 billion people, we will need to manage the

planets resources more efficiently and share them more equitably. Over the

long term, the survival of the human race depends as muchif not more

upon our way of life as upon our number.

Conclusion


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Population histograms : ranking/country

Back

1950

2000

2050


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Population histograms : ranking/country

Back

1950 1975 2000 2025 2050 1950 1975 2000 2025 2050

1

2

1

2

billions billions

Population

1950 1975 2000 2025 2050

4

8

1950 1975 2000 2025 2050

4

8

Number of

children per

woman

1950 1975 2000 2025 2050

110

220

1950 1975 2000 2025 2050

110

220

millions millions

Population

aged 65 and

above

Ppt Demography

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