How Population Change Will Transform the World

This highly informative book is essential reading for anyone wanting to understand the differential trends in world population growth. Much debate and analysis is devoted to the combination of rising numbers and rising consumption. Here the emphasis is more on the different stages of demographic transition from high birth and death rates to lower rates of childbirth and lengthening lives, leading to ageing populations. Broadly speaking, Africa is still struggling to reduce fertility, the Middle East faces the greatest challenges in terms of youth bulge and therefore unemployment, while advanced economies in Europe and the US face ageing populations. Migration plays a role at all stages, for instance in terms of labour supply and the fact that immigrants tend to have higher birth rates, which in turn will lead to a different population composition. All this is summarised in a detailed table on page 12. For the author, the fundamental challenges are to maintain wellbeing across the lifespan, to reduce inequality within generations and ensure equity between generations.

Harper analyses the historic drivers of population growth in terms of sanitation, public health, nutrition and medical advances. She introduces the term epidemiological transition, where death due to infectious diseases is replaced by chronic degenerative diseases of civilisation. She tends to account for the rise of the latter partly through extended lifespans rather than stressing the importance of lifestyle in maintaining health. Two-thirds of the world's countries are now below the population replacement level of 2.1 children per woman of childbearing age. In 1950, the European figure was 2.5, which had fallen to 1.5 by 2010. In addition to the education of women, the author attributes a part of this trend to the rise of individualism. She discusses the so-called grey burden with some interesting figures on longevity and disability, but I wondered if some of the extrapolated figures for longevity will be curbed by the rise of obesity and diabetes.

The Middle East shows the greatest demographic for insurgency, highlighting the need to provide employment opportunities for the young, an issue that applies across advanced countries and is likely to increase because of robotics. Harper shows how the youth bulge can in some cases lead to an economic demographic dividend. While discussing countries where fertility is still too high, she cites Niger and does not question the extrapolation from 16 million today to 55 million in 2050 to 140 million by the end of the century in a country where half are already without adequate food. Even the figure for 2050 it is surely wildly wrong. The final chapter considers policy options in relation to the various interconnected challenges outlined, with a useful table on page 164. The real difficulty is knowing how these factors will create complex feedback loops in view of overall age-structural changes and the continuing digital revolution. The scale of our collective challenge is revealed by figures on the last page, where we learn that, over the next 15 years, some 2 billion babies will be born, 2 billion children will need to start school and 1.2 billion young adults will need to find work in a world where the fastest growing age group will be the over 60s. A thought-provoking read from Oxford's James Martin School.