Population distribution A global population of 7 226 794 000 reached in early 2015 was very unevenly distributed, as figure 2.1 shows. Approximately 75 per cent of the world’s population lived within 1000 kilometres of a coastline, whereas less than 10 per cent lived in the Southern Hemisphere. Just over half of the world’s population now lives in urban areas, with two billion of them in 1000 urban areas of 500 000 people or more. The planet now has 26 megacities, such as Tokyo–Yokohama (Japan) and Population dynamics Mumbai (India), each with over 10 million people. 2 The highest densities of people (that is, the number of people per area, usually per square kilometre) were located in the regions of Asia and Europe, especially South and East Asia, Central and Western Geographers study population for many reasons: Europe, as well as north-east North America. Lower Figure 2.2 Tehran in Iran has a population of over 12 million people u to develop an understanding of where our fellow humans live and, collectively, how they grow, decline, population densities occurred over wide areas of age and move Africa, Australia, Northern Europe, and Western centre at the foot of the Alborz Mountains. Tehran’s u to help develop policies to mitigate the effects of population growth or decline and the impacts of and Northern Asia. Antarctica is the only continent growth has been especially rapid since the 1960s population movement without a permanent population. with the population more than tripling in number. Government authorities are planning to redistribute key u to determine how changes in population characteristics are closely related to levels of development at all scales Urban areas, like the one in figure 2.2, support some administrative functions to other urban centres as a of the highest population densities in the world. u to bring about more effective planning for the use of the Earth’s resources. way of reducing the megacity’s growth. For example, Karachi (Pakistan) has an average of Introduction 23 400 people per square kilometre while Dhaka Variations in population distribution become very evident (Bangladesh) averages 43 500 people per square at national scales. For example, China has an average The term population dynamics refers to the changes and disease. This can produce a natural increase or kilometre. These levels seem even more extreme when density of 146 people per square kilometre. However, that occur in a population, and includes how and why a natural decrease. Further, a population can age, or compared with Melbourne’s average of 1500 people the eastern region of the country supports densities these changes occur. Population change can result become younger, because of changes in birth rates per square kilometre. Remember, these densities are above 400 people. Shanghai, the region’s major urban from the difference between birth rates and death and death rates. Migration into or out of an area can only averages. There is likely to be a considerable centre, with more than 23 million people, has an rates. In turn, changes to birth rates and death rates have a further impact on population distribution, age range in density either side of the average. average population density of 3631 people per square can be the result of many factors interconnecting with and ethnicity, as well as further increase or decrease each other: for instance, changing social and economic its size. Tehran in Iran, see figure 2.2, with over 12 million kilometre. Some parts of inner Shanghai have an average conditions, government policies, wars and revolution, people in its wider metropolitan area, has densities in excess of 40 000. In contrast, the western part of the exceeding 10 000 per square kilometre in the older country has fewer than 10 people per square kilometre. Figure 2.1 Global population distribution Figure 2.3 Australia’s population distribution NOT FORArctic FURTHER Ocean NOT FOR FURTHER DISTRIBUTIONAtlantic DISTRIBUTION Ocean Tropic of Cancer Pacific Ocean Equator Indian Ocean Tropic of Capricorn Persons per square kilometre 500 and over Southern Ocean 0 2000 km 100–499 Population dynamics Equatorial Scale 5–99 u Human population People per sq km Less than 5 u 100.0100.0 or or moremore 10.010.0 to to 100.0 100.0 UNIT 4 0 1000 1.01.0 to 10.0to 10.0 CHAPTER 2 0.10.1 to 1.0to 1.0 Kilometres Less than 0.1 20 Less than 0.1 21 UNIT4 Fig 2.01 v1 6/1/16 Global population growth Until the 1750s global population growth was slow population dynamics. By 2015 world population was as both birth rates and death rates were high. Most increasing by around 77 million a year (see figures 2.7(a) societies at the time were based on agriculture, and life and 2.7(b)) — or close to over two people for each second. expectancies were low. With improvements in farming techniques producing food surpluses, and better and Future projections of world population size are based more accessible medicine and hygiene, death rates fell on individual national projections of population growth. and life expectancies increased, especially in Europe. Over long time periods, changes in fertility rates, birth As a result world population began to grow more rates and death rates (see pages 26–33 for the role rapidly. By the early nineteenth century the world’s these terms play in population change) can occur quite population had reached one billion (see figure 2.6). rapidly. Nonetheless, the United Nations projects a world population of around 9.6 billion by 2050 and It took around 120 years for the world’s population to perhaps 11 billion by the end of the century. The eight reach its second billion but just 35 years for its third biggest contributors to this likely growth are Nigeria, billion. This exponential growth — that is, growth at India, Tanzania, Congo, Niger, Uganda, Ethiopia and Figure 2.4 Urban Australia has the highest population densities. Figure 2.5 The Australian outback supports a very low population density. an increasing rate — gave rise to the term ‘population the United States. Six of these countries are in Africa Australia’s differences in population distribution explosion’. In the mid 1960s the world’s fastest growth where the total projected growth is from 2.1 billion in ACTIVITIES (see figures 2.3, 2.4 and 2.5) are the result of a of 2.1 per cent a year occurred, allowing a fourth 2014 to 4.2 billion by 2100. Nigeria’s population growth combination of many factors interacting with each billion to be reached in 1975. As figure 2.6 shows, will be Africa’s stand out: from 181 million in 2015 to 1. Define population density. How is it different to population distribution? other. Inhospitable environmental factors including the world’s population reached six billion in 1999. a projected 400 million by 2050. Europe’s share of the 2. Describe the distribution of the global population. Include place names world’s population will shrink from over 10 per cent to short growing seasons associated with low and Since the 1990s world population growth rates of at least three different regions and three different countries as well as less than six. Even Asia’s share is projected to shrink unreliable rainfall, steep topography and/or poor (see figures 2.7(a) and 2.7(b)) have slowed due to a Figure 2.6 numerical values from figure 2.1. from 60 per cent in 2015 to around 43 per cent by 2100. accessibility have led to extensive areas of low rising age for marriage, wider use of contraceptives Billions of people population density, as shown in figures 2.3 and 2.5. 3. Select a large country or region with a high population density and another and smaller families in many countries. Although 10 2050 with a low population density. These situations may be reversed by the use of local growth rates have slowed, huge increases in 9 Projected water sources such as artesian basins, the discovery absolute numbers continue to occur because the base a. Describe their global context using figure 2.1. 8 of minerals and the need for defence sites. Urban population totals remain so large. For example, there b. What variations in population density can you find within each country 2011 concentrations at port sites such as Melbourne were almost 135 million births in 2015 (and 57 million 7 or region? 1999 and Sydney, together with their growth as major deaths) compared to around 53 million births 30 years 6 administrative and manufacturing centres, account 1987 c. Research the key reasons for their contrasting population densities. earlier. Figure 2.8 summarises these changes. 5 for Australia’s highest densities. In between these 1975 4. Discuss in a group why cities can grow into megacities with over 4 extremes of low and high population densities, the The populations of China and India play special roles 1960 10 million people. Consider factors such as location, potential for trade better watered and gentle sloping lands of the east in world population data, including growth. Together 3 Population (billions) 1925 and political importance. and south-east support farming communities and these two countries account for around 36 per cent 2 1805 5. ‘There is no country or inhabited region of the world with such a low population service towns at low and medium population densities. of the global population (China 19.2 per cent, India 1 density and varied distribution as Australia.’ How far do you agree with this 16.4 per cent).