Our Shrinking Planet by Livi Bacci Massimo (review)

The question of world demographic growth, once a subject of lively debate, no longer seems as much in the spotlight. Of course, the growth rate is no longer above 2% a year as it was in 1965–1970, but according to the medium variant of United Nations projections, the world population will have grown by more than four billion by the end of this century.

In his best-selling 1968 book The Population Bomb, Paul R. Ehrlich blamed population growth for all the planet's ills. In 1972, Barbara Ward and René Dubos recalled that we have "only one Earth" to meet our needs and so had better take good care of it, while the Meadows Report of the same year emphasized "limits to growth", economic and demographic alike. The 1987 Brundtland Report stressed "our common future" and helped popularize the concept of sustainable development. In 2014, the stated intention of a book edited by Ian Goldin was to find out whether the planet was "full". Massimo Livi Bacci, meanwhile, is interested in what he calls our "shrinking" planet.

He begins by observing that our planet is 1,000 times smaller than it was 10,000 years ago when agriculture first appeared. At that time, every human being could have had at their disposal an average of 13 square kilometres of land – one-fourth the size of Manhattan Island – whereas now we each must settle for the equivalent of a soccer field to feed and house ourselves, move about, etc. Moreover, we are moving 1,000 times faster than Magellan's expedition of 1519 – that first trip around the world took a little over 1,000 days – and an inhabitant of one of the world's wealthiest countries consumes 100 times more energy than in the first days of farming. Last, economic development is particularly uneven: per capita income in the world's richest country is 400 times that in the world's poorest. Can we give credence to the "end of demography" idea on the sole pretext that world demographic growth is slowing?

However that may be, the thousand-year-old balance between survival and reproductive instincts has been broken. Biology no longer dictates demographic behaviours. Innovations have given rise to greater choice – in reproduction, for example, where contraception has made it possible to choose the number and spacing of children. So how could that balance have been maintained? In fact, the low fertility now found in some European and East Asian countries works in favour of a second demographic transition, one that is generating not only demographic ageing but also a structural imbalance between birth and death.

The current demographic pressure on the planet cannot be dissociated from lifestyle. In a chapter on land, water, and air, Livi Bacci specifies some of the environmental issues involved in population growth. Forty-six per cent (46%) of the earth's available surface is currently used to feed the planet, whereas in 1700, 8% was sufficient. Combined urbanization, economic activities, and transportation infrastructure have now taken up and "anthropized" 54% of the total available land.

In a chapter on adaptation and self-regulation, Livi Bacci discusses population dynamics in terms of the concept of a demographic system. Could some "invisible hand" guarantee a return to the earlier, now broken balance? In the past, demographic crises were followed by recuperation phases, but in contemporary demographic systems, natural factors have less impact and individuals' freedom of choice more impact. What does the sustainability principle mean demographically? Neither invariance in world population distribution nor a gradual homogenization of demographic behaviours, as Livi Bacci sees it. There can be no sustainable development, he explains, without accelerated technological investment and transfer – or slower demographic growth.

Demographic disparities and economic inequalities are population mobility factors. The pair of options Livi Bacci puts forward for meeting the challenge of sustainable development in light of international migration is radical: either poor countries become richer or poor people will continue to travel...