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SCIENCES
Geography and Demography, Field Director – Denise Pumain
Demography, Subject Head – Brigitte Baccaïni
Demographic Dynamics and Development
Coordinated by
Yves Charbit
First published 2022 in Great Britain and the United States by ISTE Ltd and John Wiley & Sons, Inc.
Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or transmitted, in any form or by any means, with the prior permission in writing of the publishers, or in the case of reprographic reproduction in accordance with the terms and licenses issued by the CLA. Enquiries concerning reproduction outside these terms should be sent to the publishers at the undermentioned address:
ISTE Ltd
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John Wiley & Sons, Inc.
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© ISTE Ltd 2022
The rights of Yves Charbit to be identified as the author of this work have been asserted by him in accordance with the Copyright, Designs and Patents Act 1988.
Library of Congress Control Number: 2021947914
British Library Cataloguing-in-Publication Data
A CIP record for this book is available from the British Library
ISBN 978-1-78945-050-7
ERC code:
LS8 Ecology, Evolution and Environmental Biology
LS8_3 Population biology, population dynamics, population genetics
SH1 Individuals, Markets and Organisations
SH1_3 Development economics, health economics, education economics
SH3 The Social World, Diversity, Population
SH3_8 Population dynamics; households, family and fertility
Introduction
Demographic Dynamics
Yves CHARBIT
CEPED, University of Paris, France
I.1. What are demographic dynamics?
Demographic dynamics come down to a fundamental equation. Every year the growth or decline of a given population (P) is reduced to the interaction of four variables:
(2020 Total population) = (2019 Total population) + (2019 births) –
(2019 deaths) + (2019 immigration) – (2019 emigration)
From this, three simple definitions follow:
– the difference between births and deaths in a year is the natural increase (natural surplus or natural deficit);
– the difference between immigration and emigration is the net migration (which can be either positive or negative). From the point of view of demographic dynamics stricto sensu, international migrations are much less important than births and deaths;
– the total growth rate is the sum of the two indicators (natural increase and net migration), divided by the population of the previous year. It is expressed as a percentage per year.
Before 1750, when mortality and birth rates were balanced, the world population growth rate never exceeded 0.5%. Between 1750 and the 1930s, it did not exceed 1%. It reached a maximum of 2.1% per year, on average, between 1950 and 1970, when mortality in developing countries fell sharply, without a decline in birth rates. Subsequently, more and more developing countries saw their fertility rate decline, as it did in industrialized countries with the end of the baby boom of the 1950s. The combined effect of these two developments led to a steady decline in the world population growth rate: 1.95% in 1970, 1.26% in 2000 and 1.09% in 2020.
Another aspect of demographic dynamics that is directly related to changes in flows must be mentioned. Their very accumulation determines population stocks. Thus, the rural exodus leads to changes in the distribution between urban and rural areas, which is the process of urbanization. As for the evolution of mortality and birth rates, this is translated by the population’s age–sex distribution, conventionally represented by a pyramid. After the Second World War, developing countries experienced a large annual number of births but, due to high mortality, very few people reached adulthood. This was reflected by broad-based pyramids. In these populations, although there certainly were adults, very few were elderly people. With the gradual decline in
