World population growth and distribution pdf
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- 2.1 Trends and causes of population growth
- The world population explosion: causes, backgrounds and projections for the future
- Population growth
- Human population growth and the demographic transition
If you create an account, you can set up a personal learning profile on the site. Figure 2. Growth is slow until the middle of the 20th century, when the gradient slope of the graph increases, indicating a change to more rapid population growth.
We construct and calibrate a model of the world economy in which countries' opportunities to develop depend on their trade with advanced economies. Trade opportunities in turn depend on the relative population of the advanced and developing world. As developing countries become advanced, they further improve the trade prospects for the remaining developing countries. As long as the population growth differential between developing and advanced countries is not too large, the rate at which countries transition to prosperity accelerates over time.
2.1 Trends and causes of population growth
If you create an account, you can set up a personal learning profile on the site. Figure 2. Growth is slow until the middle of the 20th century, when the gradient slope of the graph increases, indicating a change to more rapid population growth. The graph continues into the future to a predicted global population in in excess of 9 billion. There are many factors that influence this trend. High rates of infant and childhood deaths and short lifespans put a limit on population growth in the past.
However, improvements in nutrition, water, medical care and other technological advances have contributed to a sharp decline in deaths while births continue to increase, resulting in population growth. Look at Figure 2. How would you describe the predicted trend in world population for the middle of the 21st century?
For most of the 21st century, from to about , the trend shows a steady increase. By the middle of the century, at the far-right side of the graph, the gradient of the line on the graph is less steep — it flattens out slightly — indicating the rate of increase is expected to slow down by that date.
The main causes of death are disease, famines, accidents and war. Underlying these direct causes are interrelated contributory factors such as poverty, availability of health care, education and other social and economic factors.
Since the start of the 20th century, there has been a sharp decline in death rates and an increase in length of life due to changes in these factors, which has resulted in an ageing global population. The rates of change in population vary in different regions of the world and can be categorised into groups based on the socio-economic development status of different countries, as shown in Figure 2. Does the trend in population change shown in Figure 2. This corresponds to the slowing down of population increase shown in Figure 2.
The least developed countries continue to have a higher rate of population increase for several reasons. Significant among these is the fact that the benefits from advances in health and agriculture are not spread evenly across the world. Medical technologies, for example vaccines and antibiotics, reduce the death rate by protecting people against diseases like influenza, measles, polio and rubella.
However, vaccines are still not available for many diseases like malaria that are common in less developed countries, particularly in sub-Saharan Africa.
Other public health measures, like water and sanitation, waste management and nutritional education are very important in preventing disease and in reducing the death rate. These measures are well developed in industrialised countries but less so in developing countries. Similarly, in agricultural science and technology, advances such as new kinds of seed, fertilisers, pesticides and mechanisation in farming have transformed food production.
These have increased the quantity of food produced, which has helped to improve nutrition and decrease death rates. However, advanced food production and distribution are still developing in many countries. For further information, take a look at our frequently asked questions which may give you the support you need. Skip to main content. Explore OpenLearn. Sign in. Get started Create a course Free courses. About this course 30 hours study 1 Level 1: Introductory Course description.
Create account See more courses. View larger image. From Figure 2. Which development group has the highest annual rate of population change? More developed regions are expected to have zero growth or, in other words, a static population level. Least developed countries contribute the highest annual population change for the world in the years between and Go to next page Next 2. Print page. Have a question? Report a concern. Back to top.
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The world population explosion: causes, backgrounds and projections for the future
Population growth is the increase in the number of individuals in a population. Global human population growth amounts to around 83 million annually,  or 1. The global population has grown from 1 billion in to 7. It is expected to keep growing, and estimates have put the total population at 8. World population has been rising continuously since the end of the Black Death , around the year The most significant increase in the world's population has been since the s, mainly due to medical advancements  and increases in agricultural productivity. Due to its dramatic impact on the human ability to grow food, the Haber process , named after one of its inventors, the German chemist Fritz Haber , served as the "detonator of the population explosion ", enabling the global population to increase from 1.
The term population distribution refers to the way people are spaced over the earth's surface. Broadly, 90 per cent of the world population lives in about 10 per cent.
The world and most regions and countries are experiencing unprecedentedly rapid demographic change. The most obvious example of this change is the huge expansion of human numbers: four billion have been added since Projections for the next half century expect a highly divergent world, with stagnation or potential decline in parts of the developed world and continued rapid growth in the least developed regions. Other demographic processes are also undergoing extraordinary change: women's fertility has dropped rapidly and life expectancy has risen to new highs. Past trends in fertility and mortality have led to very young populations in high fertility countries in the developing world and to increasingly older populations in the developed world.
Human population growth and the demographic transition
When and why did the world population grow? And how does rapid population growth come to an end? These are the big questions that are central to this research article.
Not a MyNAP member yet? Register for a free account to start saving and receiving special member only perks. While there has been a steady increase of population growth during the past two or three centuries, it has been especially rapid during the past 20 years.
At the beginning of the nineteenth century, the total world population crossed the threshold of 1 billion people for the first time in the history of the homo sapiens sapiens. Since then, growth rates have been increasing exponentially, reaching staggeringly high peaks in the 20th century and slowing down a bit thereafter. Total world population reached 7 billion just after and is expected to count 9 billion by This paper first charts the differences in population growth between the world regions. Next, the mechanisms behind unprecedented population growth are explained and plausible scenarios for future developments are discussed. Crucial for the long term trend will be the rate of decline of the number of births per woman, called total fertility. Improvements in education, reproductive health and child survival will be needed to speed up the decline of total fertility, particularly in Africa.