AGRICULTURE AND HISTORY

Agriculture and the Number of Humans

The works of demographers give us an idea of the increase in the number of people over the last 50,000 years. We can look at this increase in relation to the evolution of agrarian systems in different parts of the world, such as we present in this book. On the eve of agriculture’s appearance, the human population was rapidly expanding thanks to the development of increasingly diversified and effective modes of predation. However, even if in certain places humans had reached the limits of exploitability of some species, even so far as to cause them to diminish or even disappear, nothing justifies the contention that development of agriculture and animal breeding in the Neolithic responded to the need to overcome a sort of generalized crisis of systems of predation.
It is, however, undeniable that the tenfold increase in the human population, which grew from around 5 to 50 million inhabitants between 10,000 and 5,000 years before the present, is essentially due to the planetary development of Neolithic agriculture. The systems of slash-and-burn cultivation, which developed mainly in the cultivable forested environments of the planet, supported population densities of 10 to 30 inhabitants per square kilometer, densities which are much higher than those of systems of predation.
Then, between 5,000 and 3,000 years before the present, i.e., between 3,000 and 1,000 B.C.E., the world population doubled, growing from around 50 to around 100 million individuals. This increase can be explained, to a certain extent, by the extension of slash-and-burn cultivation, but also by the development of large societies based on hydraulic agriculture in the valleys of the Indus, Mesopotamia, and the Nile. Certainly, agricultures organized around floodwaters and irrigation, which were organized in these privileged valleys, were limited in extent, but they could support impressive population densities of several hundred inhabitants per square kilometer.
In the course of the two millennia that followed, between 1000 B.C.E. and 1000 C.E., the world population more than doubled to around 250 million inhabitants, due to the development of hydraulic systems of aquatic rice growing in the valleys and deltas of China, India, and Southeast Asia and, to a lesser degree, to the development of systems of hydraulic agriculture (Olmecs, Mayas, Aztecs, pre-Inca societies) in America during this period. On the other hand, systems of cultivation based on rainwater and fallowing, which extended around the Mediterranean region and into Europe, contributed very little to this population growth, because they were not that much more productive than the slash-and-burn agriculture which they replaced.
The contribution of European agriculture to world population growth became noteworthy only with the agricultural revolution in the Middle Ages. From the eleventh to the thirteenth centuries, the development of agricultures based on fallowing and cultivation with an animal-drawn plow made it possible for the European population to triple or even quadruple. After having fallen during the great crisis of the fourteenth century, this population increased again in the sixteenth century. Then it doubled once more thanks to the agricultural revolution of the seventeenth, eighteenth, and nineteenth centuries, a revolution which gave rise to agrarian systems that did not use fallowing. But the growth in world population since the year 1000 was also due to the development of aquatic rice growing systems, particularly in Asia.
In addition, from the sixteenth century, the population of European origin grew by extending its agriculture into the temperate regions of America, South Africa, Australia, and New Zealand, to the detriment of the indigenous populations.
Finally, even today, the world demographic explosion, whatever the other reasons may be, is only made possible by a gigantic increase in the production capacities of world agriculture. This increase essentially results from the expansion and improvement of aquatic rice growing from two to three harvests per year, principally in Asia, and from the development of motorized, mechanized, and chemicalized agriculture in the developed countries and in some limited sectors of the developing countries.
For all that, however, this immense increase in the number of people should not induce us to forget that famine, undernourishment, and the persistent difficulty in meeting the needs of humanity are all very real. At the end of the twentieth century, 800 million persons suffered from chronic undernourishment and more than 2 billion were nutritionally deficient in one or several nutrients (iron, iodine, vitamin A, proteins). And it is possible to believe, as do Professor René Dumont and Lester Brown, director of the Worldwatch Institute, that the growing needs of humanity are dangerously approaching, right now, the exploitable limits of water resources, planetary fertility, and even the possibility of using photosynthesis for food production.
But if some regions are fully exploited and even sometimes dangerously overexploited, there are also many exploitable regions that are today unexploited or underexploited. More than two-thirds of the exploitable areas in the developing countries (China not included) are unexploited.And even if half of this land is in fact difficult to exploit, the possibilities for expanding agriculture are still very great.
Moreover, it is possible to believe that the twenty-first century will see the development of agrarian systems producing more basic provisions and able to support much larger population densities than the cereal- growing or pastoral systems predominant today. In fact, setting aside progress in irrigation, seed selection, and synthetic chemical agriculture, all kinds of highly productive and sustainable systems, closely combining annual cultivation, animal breeding, and arboriculture, are developing right now in the densely populated regions of the world in Southeast Asia, Central America, the Caribbean, and Great Lakes area of Africa. Systems of this type are labor intensive but not demanding in non renewable resources nor very polluting.
They formerly existed in difficult and relatively populated regions of Europe (the chestnut groves of Corsica and the Cévennes, and various forms of cultura promiscua in the Mediterranean region). Finally, in the developed countries, many uncultivated regions today could, if necessary, again enter into production if the products fetched a higher price and agricultural work were better paid. As we will see throughout this book, the overpopulation of an ecosystem is rarely absolute. It is generally relative to the capacities of the agrarian system at a given point in time. Thus, according to some people, on the eve of the Neolithic agricultural revolution, the planet, which only had several million inhabitants,was already overpopulated in relation to the means available from the system of predation.
In the tenth century, with 10 million inhabitants, France was afflicted with famine. Three centuries later, after having adopted a cultivation system based on the animal-drawn plow, it fed nearly 20 million people. Then, after the horrible food crisis and the huge number of deaths in the fourteenth century, the population was restored. Up to the end of the eighteenth century, France again appeared “overpopulated” each time its population surpassed the level of 20 million inhabitants.
At the end of the nineteenth century, however, thanks to the first agricultural revolution of modern times, France (within its current borders) fed nearly 40 million inhabitants. In the same way, for several decades, the rice-growing deltas of Asia, with only one harvest of rice per year, were considered overpopulated with 500 inhabitants per square kilometer. Today, there are well more than 1,000 inhabitants per square kilometer, thanks to the increase in output and the development of systems with two, three, or four harvests per year.

In truth, today no one knows how to estimate the planetary capacity for production of consumable biomass by humans and domestic animals without an enormous margin for error. According to the distinguished Department of Agricultural Research at the University of Wageningen, this production capacity could be 30 billion (at nearly 50 percent) to 72 billion tons of cereal-equivalent per year according to the type of agriculture practiced, with varying degrees of synthetic chemical use, or 7 to 18 times more than current production (which is around 4 billion tons of cereal-equivalent per year). That is enormous! Nevertheless, this estimate does not make it possible to know absolutely how many billions of people world agriculture will be able to feed at any particular future moment. The whole question is indeed to know what part of this potential will be effectively used in a particular time frame, who will benefit from it, up to what point, and who will be excluded from it.

By MARCEL MAZOYER and LAURENCE ROUDART Translated by JAMES H. MEMBREZ in the book 'A HISTORY OF WORLD AGRICULTURE - From the Neolithic Age to the Current Crisis', Earthscan, London, 2006. Adapted and illustrated by Leopoldo Costa.