The other factor, the evolution of the fertility rate, is much more uncertain but of critical importance in the long term. The rate at which the further growth of the world population can be slowed down is primarily dependent on the extent to which the fertility rates will continue to decline.
I will further elaborate on this notion in the next paragraph. After that, I will clarify the notion of population momentum. A further decline remains uncertain there. Figure 4 shows the evolution per world region between and , plus the projected evolution until The numbers before illustrate three things.
First of all, on all continents there is a decline going on. Secondly, this decline is not equal everywhere. And thirdly: the differences between the continents remain large in some cases. Asia and Latin America have seen a similar decline in fertility: from 5. Their fertility level has been below replacement levels for years.
Africa has indeed seen a global decrease of fertility, but the average number of children is still at an alarmingly high level: the fertility merely decreased from 6. These continental averages hide a huge underlying diversity in fertility paths. Figure 5 attempts to illustrate this for a number of countries. Firstly let us consider two African countries: the Congo and Niger. For the next decades a decline to 4 children per woman is expected.
But that is not at all certain: it is dependent on circumstances that will be further explained in a moment. The demographic transition is after all not a law of nature but the result of human actions and human institutions. Around , Pakistan and Iran had more or less the same fertility level as Niger, but both countries have seen a considerable decline in the meantime. In Pakistan the level decreased slowly to the current level of 3 children per woman.
In Iran the fertility decreased more abruptly, faster and deeper to below the replacement level — Iran today has one of the lowest fertility levels in the world, and a further decline is expected. The decrease started earlier than in Iran but happened more gradually. Today both countries have the same total fertility, below the replacement level.
Which factors cause the average number of children to go down? The literature concerning explanations for the decrease in fertility is vast and complex, but two factors emerge as crucial in this process: education and child survival. Considering child survival first: countries combining intensive birth control with very high child mortality are simply non-existent.
The statistical association between the level of child mortality and fertility is very tight and strong: in countries with high child mortality, fertility is high, and vice versa. This statistical correlation is very strong because the causal relation goes in both directions; with quick succession of children and therefore a lot of children to take care for, the chances of survival for the infants are lower than in those families with only a limited number of children to take care of — this is a fortiori the case where infrastructure for health care is lacking.
A high fertility level thus contributes to a high child mortality. And in the other direction: where survival chances of children improve, the fertility will go down because even those households with a lower number of children have increasing confidence in having descendants in the long term. It is crucial to understand that the decline in child mortality in the demographic transition always precedes the decline in fertility. Better health care is therefore essential, and a lack of good health care is one of the reasons for a persistently high fertility in a country like Niger.
Education is another factor that can cause a decline in fertility. This is probably the most important factor, not just because education is an important humanitarian goal in itself apart from the demographic effects , but also because with education one can kill two birds with one stone: education causes more birth control but also better child survival recently clearly demonstrated by Smith-Greenaway , which in its turn will lead to better birth control.
The statistical correlation between level of education and level of fertility is therefore very strong. Firstly, education enhances the motivation for birth control: if parents invest in the education of their children, they will have fewer children, as has been demonstrated. Secondly, education promotes a more forward-looking lifestyle: it will lead people to think on a somewhat longer term, to think about tomorrow, next week and next month, instead of living for the day.
This attitude is necessary for effective birth control. The influence of education on birth control has been demonstrated in a vast number of studies James et al. It starts with primary education, but an even larger effect can be attained by investment in secondary education Cohen, Women who did finish primary school have on average 6.
The fertility of Niger would be a lot lower if more women could benefit from education. The tragedy of that country is that too many people fall in the category of those without a degree of primary school, with all its demographic consequences. One achieves with education therefore a plural beneficial demographic effect on top of the important objective of human emancipation in itself.
It is one thing to get people motivated to practice birth control but obtaining actual effective contraception is quite another matter. Information concerning the efficient use of contraceptives and increasing the accessibility and affordability of contraceptives can therefore play an important role.
Investments in services to help with family planning are absolutely necessary and could already have great results in this group of women.
There is often a problem of lack of motivation for birth control on the one hand, as a result of high child mortality and low schooling rates, and a lack of power in women who may be motivated to limit fertility but are confronted with male resistance on the other Blanc, ; Do and Kurimoto, Empowerment of women is therefore essential, and education can play an important role in that process as well. Even if all the people would suddenly practice birth control much more than is currently considered possible, the world population would still continue to grow for a while.
This is the consequence of population momentum, a notion that refers to the phenomenon of demographic inertia, comparable to the phenomenon of momentum and inertia in the field of physics. Demographic growth is like a moving train: even when you turn off the engine, the movement will continue for a little while. The power and direction of population momentum is dependent on the age structure of the population.
Compare the population pyramids of Egypt and Germany Fig. The one for Egypt has a pyramidal shape indeed, but the one for Germany looks more like an onion. As a consequence of high birth rates in the previous decades, the largest groups of Egyptians are to be found below the age of forty; the younger, the more voluminous the generation. Even if the current and future generations of Egyptians would limit their fertility strongly as is indeed the case , the birth rate in Egypt would still continue to rise for quite some time, just because year after year more and more potential mothers and fathers reach the fertile ages.
Egypt therefore clearly has a growth momentum. Germany on the other hand has a negative or shrinking momentum: even if the younger generations of Germans would have a larger num ber of children than the generation of their own parents, the birth rate in Germany would still continue to decrease because fewer and fewer potential mothers and fathers reach the fertile ages.
The concerns about the consequences of population explosion started in the sixties. In the world population debate, the general concerns involve mainly three interconnected consequences of the population explosion: 1 the growing poverty in the world and famine; 2 the exhaustion and pollution of natural resources essential to human survival; and 3 the migration pressure from the poor South to the rich North Van Bavel, The Malthusian line of thought continues to leave an important mark on the debate regarding the association between population growth and poverty: Malthus saw an excessive population growth as an important cause of poverty and famine.
Rightfully this Malthusian vision has been criticized a lot. One must after all take the reverse causal relation into account as well: poverty and the related social circumstances like a lack of education and good health care for children contribute to high population growth as well. Concerning famine: the production of food has grown faster since than the world population has, so nowadays the amount of food produced per person exceeds that which existed before the population explosion Lam, Often regions with famine have ecological conditions permitting sufficient production of food, provided the necessary investments in human resources and technology are made.
The most important cause of famine is therefore not the population explosion. Famine is primarily a consequence of unequal distribution of food, which in turn is caused by social-economic inequality, lack of democracy and civil war. Poverty and famine usually have mainly political and institutional causes, not demographic ones.
The Malthusian vision, that sees the population explosion as the root of all evil, therefore has to be corrected Fig.
Rapid population growth can indeed hinder economical development and can thus pave the way for poverty. But this is only part of the story. As mentioned, poverty is also an underlying cause of rapid population growth.
Social factors are at the base of both poverty and population growth. The impact of the population explosion on the environment is unquestionably high, but the size of the population represents only one aspect of this.
The ecological footprint of the world population has increased tremendously the past decades and the growth of the world population has obviously played an important role in this. The considerable increase in the Chinese ecological footprint of the past decades for example, is more a consequence of the increased consumption of meat than of population growth Peters et al. The consumption of water and meat in the world is increasing more rapidly than the population 3. The consumption of water per person is for example threefold higher in the US than in China Hoekstra and Chapagain, The African continent has at present the same number of inhabitants as Europe and North America together, over 1 billion.
But the total ecological footprint of Europeans and Americans is many times higher than that of Africans Ewing et al. In contrast, we know of the population growth that it will continue for some time anyhow, even if people in poor countries would practice much more birth control than we consider possible at present. The population explosion has created an increasing migration pressure from the South to the North — and there is also important migration within and between countries in the South.
In absolute terms, this would result in an exponential increase in the number of people. But, as we see in this chart, since the s the growth rate has been falling. This means the world population is not growing exponentially — for decades now, growth has been more similar to a linear trend.
The previous section looked at the growth rate. This visualization here shows the annual global population increase from to today and the projection until the end of this century. The absolute increase of the population per year has peaked in the late s at over 90 million additional people each year. But it stayed high until recently. From now on the UN expects the annual increase to decline by around 1 million every year. There are other ways of visually representing the change in rate of world population growth.
Two examples of this are shown in the charts below. The visualization shows how strongly the growth rate of the world population changed over time. In the past the population grew slowly: it took nearly seven centuries for the population to double from 0. As the growth rate slowly climbed, the population doubling time fell but remained in the order of centuries into the first half of the 20th century. Things sped up considerably in the middle of the 20th century.
The fastest doubling of the world population happened between and a doubling from 2. This period was marked by a peak population growth of 2. Since then, population growth has been slowing, and along with it the doubling time.
In this visualisation we have used the UN projections to show how the doubling time is projected to change until the end of this century. By , it will once again have taken approximately years for the population to double to a predicted This visualization provides an additional perspective on population growth: the number of years it took to add one billion to the global population.
This visualisation shows again how the population growth rate has changed dramatically through time. By the third billion, this period had reduced to 33 years, reduced further to 15 years to reach four. The period of fastest growth occurred through to , taking only 12 years to increase by one billion for the 5th, 6th and 7th.
The world has now surpassed this peak rate of growth, and the period between each billion is expected to continue to rise. Two hundred years ago the world population was just over one billion. Since then the number of people on the planet grew more than 7-fold to 7. How is the world population distributed across regions and how did it change over this period of rapid global growth? In this visualization we see historical population estimates by region from through to today.
If you want to see the relative distribution across the world regions in more detail you can switch to the relative view. The world region that saw the fastest population growth over last two centuries was North America. The population grew fold. Latin America saw the second largest increase fold. Over the same period the population Europe of increased 3-fold, in Africa fold, and in Asia 6-fold. The distribution of the world population is expected to change significantly over the 21st century.
We discuss projections of population by region here. Over the last century, the world has seen rapid population growth. But how are populations distributed across the world? Which countries have the most people? In the map, we see the estimated population of each country today. By clicking on any country, you can also see how its population has evolved over this period. You can learn more about future population growth by country here. This series of maps shows the distribution of the world population over time.
The first map — in the top-left corner — shows the world population in BC. Global population growth peaked in the early s. But how has population growth varied across the world? Migration flows are not counted. Both of these measures of population growth across the world are shown in the two charts.
You can use the slider underneath each map to look at this change since Clicking on any country will show a line chart of its change over time, with UN projections through to We see that there are some countries today where the natural population growth not including migration is slightly negative: the number of deaths exceed the number of births. When we move the time slider underneath the map to past years, we see that this is a new phenomenon.
Up until the s, there were no countries with a negative natural population growth. Worldwide, population growth is slowing—you can press the play arrow at the bottom of the chart to see the change over time.
Overall, growth rates in most countries have been going down since the s. Yet substantial differences exist across countries and regions. Moreover, in many cases there has been divergence in growth rates. One of the big lessons from the demographic history of countries is that population explosions are temporary. For many countries the demographic transition has already ended, and as the global fertility rate has now halved we know that the world as a whole is approaching the end of rapid population growth.
This visualization presents this big overview of the global demographic transition — with the very latest data from the UN Population Division. As we explore at the beginning of the entry on population growth , the global population grew only very slowly up to — only 0. In the many millennia up to that point in history very high mortality of children counteracted high fertility.
The world was in the first stage of the demographic transition. Once health improved and mortality declined things changed quickly. Particularly over the course of the 20th century: Over the last years global population more than quadrupled.
As we see in the chart, the rise of the global population got steeper and steeper and you have just lived through the steepest increase of that curve. This also means that your existence is a tiny part of the reason why that curve is so steep. To provide space, food, and resources for a large world population in a way that is sustainable into the distant future is without question one of the large, serious challenges for our generation.
We should not make the mistake of underestimating the task ahead of us. Yes, I expect new generations to contribute , but for now it is upon us to provide for them. Population growth is still fast: Every year million are born and 58 million die — the difference is the number of people that we add to the world population in a year: 82 million.
In red you see the annual population growth rate that is, the percentage change in population per year of the global population. It peaked around half a century ago. Peak population growth was reached in with an annual growth of 2. This slowdown of population growth was not only predictable, but predicted. Just as expected by demographers here , the world as a whole is experiencing the closing of a massive demographic transition. This chart also shows how the United Nations envision the slow ending of the global demographic transition.
As population growth continues to decline, the curve representing the world population is getting less and less steep. By the end of the century — when global population growth will have fallen to 0. It is hard to know the population dynamics beyond ; it will depend upon the fertility rate and as we discuss in our entry on fertility rates here fertility is first falling with development — and then rising with development. The question will be whether it will rise above an average 2 children per woman.
The world enters the last phase of the demographic transition and this means we will not repeat the past. The global population has quadrupled over the course of the 20th century, but it will not double anymore over the course of this century. We are on the way to a new balance.
The big global demographic transition that the world entered more than two centuries ago is then coming to an end: This new equilibrium is different from the one in the past when it was the very high mortality that kept population growth in check. In the new balance it will be low fertility keeps population changes small.
In there were 2. Now in , there are 7. By the end of the century the UN expects a global population of This visualization of the population pyramid makes it possible to understand this enormous global transformation. Population pyramids visualize the demographic structure of a population. The width represents the size of the population of a given age; women on the right and men to the left.
The bottom layer represents the number of newborns and above it you find the numbers of older cohorts. Represented in this way the population structure of societies with high mortality rates resembled a pyramid — this is how this famous type of visualization got its name.
In the darkest blue you see the pyramid that represents the structure of the world population in Two factors are responsible for the pyramid shape in An increasing number of births broadened the base layer of the population pyramid and a continuously high risk of death throughout life is evident by the pyramid narrowing towards the top.
There were many newborns relative to the number of people at older ages. The narrowing of the pyramid just above the base is testimony to the fact that more than 1-in-5 children born in died before they reached the age of five.
Through shades of blue and green the same visualization shows the population structure over the last decades up to You see that in each subsequent decade the population pyramid was fatter than before — in each decade more people of all ages were added to the world population. If you look at the green pyramid for you see that the narrowing above the base is much less strong than back in ; the child mortality rate fell from 1-in-5 in to fewer than 1-in today.
In comparing and we see that the number of children born has increased — 97 million in to million today — and that the mortality of children decreased at the same time. If you now compare the base of the pyramid in with the projection for you see that the coming decades will not resemble the past: According to the projections there will be fewer children born at the end of this century than today.
The base of the future population structure is narrower. We are at a turning point in global population history. Between and today, it was a widening of the entire pyramid — an increase of the number of children — that was responsible for the increase of the world population.
As global health is improving and mortality is falling, the people alive today are expected to live longer than any generation before us. This is now happening at a global scale. For every child younger than 15 there were 1. Richer countries have benefited from this transition in the last decades and are now facing the demographic problem of an increasingly larger share of retired people that are not contributing to the labor market.
In the coming decades it will be the poorer countries that can benefit from this demographic dividend. The change from to today and the projections to show a world population that is becoming healthier.
When the top of the pyramid becomes wider and looks less like a pyramid and instead becomes more box-shaped, the population lives through younger ages with very low risk of death and dies at an old age.
The demographic structure of a healthy population at the final stage of the demographic transition is the box shape that we see for the entire world for The world population has grown rapidly , particularly over the past century: in there were fewer than 2 billion people on the planet; today there are 7. The change in the world population is determined by two metrics: the number of babies born, and the number of people dying.
The line chart shows the same data, but also includes the UN projection until the end of the century. It is possible to switch this chart to any other country or world region in the world. The economy of the nation, which gained independence from Portugal in , was boosted by the discovery of gas fields off the coast in Uganda has done well when it comes to dealing with health crises. For example, it has contained several Ebola outbreaks over the years.
However, this week Uganda is dealing with renewed concerns over that disease, which may have been carried to Uganda from neighboring Democratic Republic of Congo. The country may be facing another kind of crisis, as the population of this eastern African nation is projected to climb to The population is surging because of a lack of family planning, and the government is worried about pressure on resources and rapid urbanization.
The Gambia is one of the least populous countries in Africa, with a population of just over 2. Though relatively small, the country's population has increased by Currently, the population density is about people per square kilometer, and undoubtedly there will be less room to roam in the coming decades.
Though it ranks at No. Tanzania borders the Indian Ocean, between Kenya and Mozambique. Its inhabitants are spread out over an area more than twice the size of California.
Tanzania's growing population also includes migrants and refugees. The nation has enjoyed domestic stability and is home to two of Africa's biggest tourist attractions - Africa's highest mountain, Kilimanjaro, and national parks such as the Serengeti.
With an annual birth rate of 45 births per 1, residents, Mali is in a three-way tie with Angola and Chad for the second-highest birth rate on Earth. A declining mortality rate coupled with a steady fertility rate has been fueling growth in the West African country of Burkina Faso. The nation hasn't reached its health goals for mothers and children, but there has been an improvement in the maternal mortality rate as well as survival rates for children under age 5.
Though Burkina Faso suffers from food shortages and poverty, the country attracts migrants and refugees from nearby countries. Between and , the population of Chad grew from 3 million to Life expectancy has increased, from a brief 38 years in to 52 years for males and 54 for females as of Still, it is considerably below the global average life expectancy of 72 years.
Population in the Syrian Arab Republic, usually referred to simply as Syria, has actually dropped in recent years because of the ongoing effects of the civil war that has been raging there since
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