Cover page

Title page

Copyright page

Author's Note

The data cited in this book come mostly from official sources, from the United Nations to the Food and Agriculture Organization and the World Bank. More specifically, the population data from 1950 onward are drawn from the UN's World Population Prospects: The 2015 Revision (, unless otherwise indicated. The data subsequent to 2015 are drawn from the same source, on the basis of the so-called ‘median variant’ of UN projections (there is also a ‘low’ and ‘high’ variant). In practice, the median variant is based on reasonable, widely accepted hypotheses as to how demographic variables will develop in the future. It can be used as a genuine prediction, ignoring the UN's own semantic subtleties in distinguishing between ‘prospects’ and ‘predictions’. In the text I have used the expressions ‘developed countries’, ‘rich countries’, and ‘western countries’ interchangeably, and so, too, the opposite expressions ‘developing countries’, ‘less developed countries’, and ‘poor countries’. According to the UN classification, the developed countries are the countries of Europe and North America as well as Japan, Australia, and New Zealand. All the others are ‘less developed countries’ (even if some of them are quite developed today). In the text I often make reference to two overall indices: the mean number of children per woman; and life expectancy at birth. The former measures the average number of children born to a woman who survives through the entire fertile life cycle (and thus it overlooks mortality). Life expectancy (understood to mean life expectancy at birth, unless some other age is explicitly mentioned) represents the mean number of years lived by a newborn during her life, subject to the risks of death prevalent across all age groups at the moment of birth.


The planet has got smaller. A thousand times smaller.

In the age of the birth of agriculture, 10,000 years ago, the 10 million human beings who populated the Earth (theoretically) had at their disposal some 13 km2 of land each – an area equivalent to a quarter of the island of Manhattan per head. By 2050 there will be 10 billion of us, and the area at the disposal of each human being will be 10,000 times smaller – of the dimensions of a football pitch.

The first journey circumnavigating the world, completed by the Magellan–Elcano expedition, set off from Seville on 10 August 1519 and arrived back there on 8 September 1522, after a 1,125-day voyage. Today it takes just one day for a supersonic plane to circumnavigate the globe. It is 1,000 times faster.

The early agriculturists could draw on a few thousand calories a day: their own bodily and muscular energy, the energy provided by beasts of burden, and the energy that streams supplied to mills and the wind to sails. In our own time, an inhabitant of any of the richest countries can draw on 100 times more energy each day.

There are 1,000 times more of us, 1,000 times poorer for space; 1,000 times faster in travelling across it; 100 times greedier for energy. It should be understood that these are but crude averages in a world in which the space that people are provided with, their capacity to move around, and the energy available to them are distributed in an extremely unequal manner. But how unequal? Taking individual countries as our reference, in 2013 the GDP per capita in the richest country (Norway, at $102,700) was almost 400 times greater than that in the poorest (Burundi, at $260).

Our Shrinking Planet discusses some of the most crucial questions of our current century, linked to the Earth's population and the very powerful growth differentials across different countries, regions, and continents. Many interpret the slowdown of the planet's population growth as the sign of a coming ‘end of demography’, with the advent of a zero-growth world with homogeneous reproductive behaviours, universally low mortality rates, and the exhaustion of international migration. Yet never as in the present era has geodemography – a close relative of geopolitics – passed through such choppy waters. However, the population question does seem to be silently slipping off the international agenda. It is almost as if the failure of the ‘demographic timebomb’ to detonate (and this is how rapid population growth was irresponsibly defined half a century ago) gave us permission not to worry about the 3 or 4 billion extra people whom we will have to take in, feed, clothe, house, educate, and get working before the end of the century. And these extra people will also have a considerable impact on the environment.

We should be reassured by the fact that the international community has now adopted the principle of sustainability. This is certainly a positive thing, though this sacrosanct principle also risks changing into an acritical mantra, according to which everything must be ‘sustainable’ without this principle itself being given any binding definition. When we are looking at natural and physical phenomena, it is possible to define this term, however difficult that may be; but when it comes to social phenomena, it remains indistinct. The population question, for example, has been relegated to a secondary role among the forthcoming sustainable development goals that the international community is now preparing to pursue. Yet uncontrolled demographic growth in sub-Saharan Africa, the reproduction deficit in Europe and a good part of East Asia, the lack of the slightest international governance of migration, human intrusion into precarious environments, and the waste of space in ungoverned settlements all pose serious threats to sustainability.

With the arrival of the twenty-first century we can see many limits looming on the horizon. More than half of the globe has been altered by human intervention, whether directly or indirectly. Longevity continues to increase, but by any reasonable estimate lifespans cannot extend much further. In some parts of the world reproductivity has hit unprecedented historic lows, while in other regions it remains unchanged, close to the maximums that biology allows. Physical limits and barriers are being placed to block international migration flows. Even the weight of the human body will fall to its minimal limits among the billion malnourished, at the same time as it reaches its maximum among the growing ranks of the obese.

I repeatedly deal with these themes throughout this book, underlining the complex relations between population, development, and politics. The international community's guiding star must be the dismantling of the Malthusian trap that still ensnares one billion people: poverty, malnutrition, precarious survival, high fertility, high population-growth rates, and thus fresh poverty. This trap was tough to crack in Malthus's time, but today, with the availability of new knowledge and greater resources, we can neutralise and dismantle it. The other goal is to strengthen the demographic quality of human capital: a well-informed freedom to choose, orient, and plan our own behaviours. That is, a well-informed freedom in sealing unions and marriages; in deciding whether to have children; in adopting means of consumption and lifestyles that favour survival; and in moving across territory.

The planet has got 1,000 times smaller. Let's be wise about how we live on it.

Florence, June 2015