The Human Tide: How Population Shaped the Modern World

This book is about the often neglected importance of demography in economic and political history, its impact on political thinking, the power politics of nations and empires and on ethnic cleavages within countries. The balance of power between different countries and regions of the world has been influenced not just by their economic development, but also by their changing populations.

The book begins with a description of the first episode of rapid and sustained population growth in history, that of Britain during the Industrial Revolution. The economic and political consequences of the Industrial Revolution have been widely studied, but as the author points out, the role that sheer numbers played in Britain’s imperial expansion has not been properly acknowledged. If the common language of the world today is English, this is because the English were the first to break through the Malthusian equilibrium of high death and birth rates. As death rates fell, the English population soared and English emigrants populated North America, Australia and New Zealand, and conquered many more countries.

As other countries like Germany, France and Russia went through their own population explosions, this increased their power relative to the British, although, of course, growth in per capita incomes was important too. The rise in U.S. population growth, which allowed it to become the world’s largest economy, enabled it to take over from Britain as the world’s superpower in the 20^th century.

Eventually, with a lag of several decades, birth rates followed death rates down, and populations stabilised in the developed world. This is known as the demographic transition between the long Malthusian period of very slow population growth that lasted from the beginning of agriculture to the Industrial Revolution, to the new stable populations, with much lower birth and death rates, accompanied by a tripling of life expectancy. In Europe, the population explosion that accompanied this process was somewhat muted by emigration to the European colonies.

The developing world began its own demographic transition only in the last hundred years or so. Without colonies to absorb emigrants, and with the availability of better medical technology, the entire process has been more explosive. The population in India has expanded by a factor of four as death rates fell in the 20th century. Much of East Asia has completed the transition to low birth rates and stable or declining populations. In South Asia, while birth rates have fallen, the population is still growing although the growth rate is declining. Africa is still in the early stages of the transition with an exploding population due to still high birth rates.

The book is curiously unsatisfactory because it spends hardly any time discussing the causes of the transition. Why did death rates fall? Why did birth rates eventually follow them down? The author simply says that when women have the education and the access to birth control, then they eventually start reducing their family size. There have been reversals of the pattern of falling death rates and birth rates and rising life expectancy, with post-Soviet Russia being the outstanding case. The reversal of otherwise increasing life expectancy in Russia is a warning that progress cannot be taken for granted.

The book is especially good at British, British colonial, and European demographic history. Its weakness is its Euro-centrism despite the last few chapters being about the non-European world. These chapters lack depth and betray the author’s lack of familiarity with the subject matter.

While the author pays a lot of attention to the effect of demography on international politics, he is silent on its effect on economics and internal politics. The large increase in population in India and other developing countries has the effect of reducing wages by enlarging the supply of workers competing for jobs. The resulting increase in inequality in turn affects politics. The dramatic effect of the AIDS epidemic in South Africa has been studied by the economist Allwyn Young, who showed that the death of a significant number of people of working age has had the effect of bidding up wages and moderating the extremely unequal income distribution in that country.

It is perhaps Euro-centrism that also leads the author to never mention the environmental and ecological consequences of the world’s population explosion. The explosive growth in human populations has led to a situation in which the majority of the natural ecosystems of the planet, have, in the last 200 years, been converted to agriculture, and to urban landscapes. The stresses and strains from this process are obvious even in the white man’s world, but loom much larger elsewhere. In the era of climate change that threatens human civilisation, this is an extraordinary omission. This would have been a much better book if the author had been able to see both the positive and negative effects of demographic change.

The Human Tide: How Population shaped the Modern World by Paul Morland (John Murray, 2019)

E. Somanathan is Professor, Economics and Planning Unit and Professor-in-Charge, Social Sciences Division, Indian Statistical Institute, Delhi.

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