Peoplequake

The subject of population often comes up at party conversations about the environment. However, very few people are aware of all the dimensions of this issue, focusing principally on growth in numbers in developing countries. What really counts is the overall impact of humans on the environment, which can be expressed through an equation formulated by Paul Ehrlich in the late 1960s, namely that impact is a function of population times affluence (or consumption) times technology (I = P x A x T). In this sense, consumption turns out to be far more significant than absolute numbers when one considers that the impact of one American is the equivalent of 40 Africans. So economically developed countries also have a population problem when one thinks in terms of impact.

Projections for maximum human population have actually been coming down over the last 20 years. UN figures for the early 1990s indicated a maximum of between 12 and 14 billion, while the latest estimates indicate 9.5 billion by the mid to late 21st century, other things being equal. These numbers conceal very different trends. Most of the population increase will take place in Third World countries, and a lot of that in cities and slums. The current slum population of 1 billion is expected to rise to 2 billion by 2050. Already, for the first time, more than half the human population lives in urban environments. In Europe, on the other hand, indigenous populations are way below replacement fertility rates, so Europe's share of world population will continue to diminish. And their economies will require further migrant labour in order to be sustained at present levels. The same will apply to relations within countries, where different ethnic groups have varying fertility rates. Africa's share of the world population will increase substantially.

It turns out that the main driver of these social changes is the transformation in the role of women. This is obvious in developed economies where women are playing a much more active role and postponing having families into their 30s while establishing their careers, then rarely having more than two children. However, similar attitudes are spreading to places like Pakistan and Bangladesh, where young women also express a preference for smaller families. This represents a shift away from patriarchal structures towards self-determination by women who are playing the most active role in contraception. There are widespread policies encouraging sterilisation, and overall this means that there is more sex with fewer babies, representing what has been called a reproductive revolution.

Pearce cites some specific examples of population decline in Europe, for instance in the former East Germany and Russia, where the life expectancy among men has fallen to 59, and the population is expected to contract to 103 million by 2050. This will have considerable economic and political repercussions. At the same time, the population of Yemen, which was 5 million in 1950, will also have risen to 103 million by the same date, if the effect of water shortages can be circumvented. These population declines also mean an ageing population - the world's women are having too few babies to sustain present populations, and this may even lead to a population implosion. In some places, there are only 300 women of childbearing age where there were 1,000 a generation ago. The indigenous population of Europe could halve by mid-century and the population of Italy could crash from 58 million to only 8 million. This will inevitably mean people working longer, but at the same time modern technology is blurring the distinction between work and the rest of life. In the meantime, we will still have to feed a rising population on a diminishing environmental resource base, about which Pearce has written an excellent book, When Rivers Run Dry. It is popular to observe that the Green Revolution defeated Paul Ehrlich's predictions of widespread famine, but we still have 1 billion severely undernourished in our current system, and these people are particularly vulnerable to rising food prices as they have to spend a much larger proportion of their income on food – hence the danger of food riots leading to political instability. But there are also signs of hope – millions of trees are being planted worldwide, which combats erosion and provide shelter from the wind as well as fodder for livestock. The last part of the book looks at the implications of the longevity revolution under the banner 'older, wiser, greener'. By 2050, there will be 1.5 billion people aged over 65 in the world, 1.2 billion of whom will be in the developing world. We have to transform attitudes from the old being a burden to looking on them as a resource. The future in the next century should be one of low mortality and low fertility after the world as a whole has passed through the demographic transition. However one factor is missing from Pearce's analysis, namely the effect of obesity on life expectancy- the US has moved from 21st to 40th in the longevity league in the last ten years. The old can only be a resource if they are healthy. This book will certainly transform your understanding of population issues.