A NEW GREEN HISTORY OF THE WORLD

THE ENVIRONMENT AND THE COLLAPSE OF GREAT CIVILISATIONS

CLIVE PONTING

VINTAGE BOOKS              2007

PART XI

Chapter 11: The Weight of Numbers

One of the greatest changes in human history has been the unprecedented and rapid increase in population over the last 250 years.

• The total number of people in the world first reached one billion in about 1825, and it had taken about 2 million years to reach this level.
• The next billion was added in only 100 years.
• A further billion (taking the total to 3 billion) took about 35 years from 1925 to 1960.
• The next billion was added in only 15 years (by 1975) and the next billion took about 12 years until the late 1980s.
• In the next 12 years another billion was added, bringing the world’s population to 6 billion just before 2000.
• The number of people in the world is now about 6½ billion.
• The rise in population was a world-wide phenomenon that began in the mid-18^th century and the exact causes are unclear,
• The pattern of population growth varied from continent to continent.

The change from a high birth rate and high mortality rate to low birth rate and a lower mortality rate is known as the ‘demographic transition’ and it took some 150 years to accomplish in the industrialized world. In the rest of the world this transition occurred later but much more rapidly, although in many parts of the world it is still far from complete.

• In Asia the rate of population growth from 1750 to 1900 was about half that of Europe so that numbers only grew from about 500 million to about 950 million.
• The huge growth in population took place in the 20^th century when numbers more than tripled whereas Europe’s did not even double.

In Africa the pattern was even more extreme. The population hardly increased at all between 1750 and 1900 and then rose more than 5-fold in the 20^th century. The pattern of growth in the Americas (and Oceania) was strongly influenced by immigration but in Latin America the population rose 7-fold in the 20^th century.

Much of the increase in these areas of the world was the result of the very rapid decline in mortality in the mid-20^th century. In Egypt the mortality rate fell by half in the 25 years after 1946 – in Sweden a similar fall took from 1800 to 1920. There was then a time lag before the shift to a lower fertility rate occurred – overall the average number of children per woman in the developing countries fell from over 6 to about 3 in the half century after 1950. But the decline was patchy. In China the demographic transition was completed by the end of the 20^th century – the number of children per woman was at European levels partly because of a strong government programme of incentives and penalties to achieve this goal. Most of Asia has followed a similar patter. However, in Africa on average 5 children are still born to each woman – about the level found in England in 1750. The impact of all these changes meant that the peak of world population growth occurred in the late 1960s at just over 2% a year. By the end of the century it had fallen back to just over half this level. However, the peak of excess births over deaths did not occur until the early 1990s when the world’s population was increasing at just over 90 million every year.

There are now more than 7 times as many people in the world as there were only two centuries ago. This unprecedented rise has had a profound effect on the environment. All of these people have had to be housed and therefore the number and size of human settlements across the globe has increased dramatically. At the same time they have consumed more of the earth’s resources in terms of energy and minerals. In doing so they have increased the amount of pollution in the world. However, in all these cases the increases have been far more than the 7-fold increase in population for reasons that are discussed in the next 5 chapters. But first and foremost the rapidly increasing population had to be fed. The way in which this has been done, and the consequences for the environment, is the theme of the rest of this chapter.

The expansion of agriculture

In the period up until the 18^th century the limit to the food supply was mainly set by the amount of land available for cultivation, the level of agricultural productivity and technology, the amount of trade in food and the proportion taken by the non-productive elements in society. In the last two centuries or so there have been revolutionary changes in most of these areas. The fact that the earth now supports seven times as many people as it did only 200 years ago seems, at first glance, to be a triumph of human ingenuity in getting round the limitations on food supply that had prevailed for thousands of years and restricted the growth in human numbers to very low levels. However, many fundamental problems have remained unresolved, many have worsened, the impact on the environment has been profound and it is far from clear that the advances of the last 2 centuries can be continued.

• In the last 300 years  the amount of pasture in the world has increased by 680% and the amount of cropland by 560%. This has been paralleled by a 43% drop in the grassland area and a 22% fall in the amount of forest and woodland.
• By the end of the 20^th century (after 10,000 years of farming) about a third of the world’s vegetated area was covered in domesticated plants and pasture.
• One of the most important trends was, as we have seen, the increasing political and economic control that Europe exercised over the rest of the world.
• Across the world in the 60 years after 1860 about half a billion hectares of new land was brought into cultivation, mainly in the United States and Russia.
• Overall in the period 1860-1960 the area under crops in the United States increased 2½-fold, in Russia/Soviet Union it quadrupled, in Canada it rose 8-fold and in Australia it was 27 times larger at the end of the period than at the beginning.
• For most of the 20^th century the expansion of cropland took place away from the temperate areas of the world and was concentrated in the tropical area – west Africa, the interior of South America and Indonesia.
• The area under crops in Brazil rose 6-fold between 1930 and 1970 and then accelerated still further as the Amazon area was opened up.
• This new agricultural land depended upon two major technological changes that created a world trade in the second half of the 19^th century: fast, cheap transport; and the development of refrigeration and freezing.
• In parallel with these developments in the European settlement colonies the European states in their other colonies began to remake the economies to produce the goods that Europe wanted.
• The result of all these changes was a vast increase in the amount of food traded in the world.
• In the 1850s total exports were no more than 4 million tonnes. By the late 20^th century they had reached nearly 250 million tones (a more than 60-fold increase in the space of 150 years.)
• The 19^th century therefore marked the beginning of the end of several thousand years of largely self-sufficient agriculture with only limited trading in a few luxury items.
• European countries, especially Britain, became dependent on imported food in the late 19^th century and it was one of the major factors that enabled them to industrialise on such a large scale and sustain highly urbanized populations.
• In the early 20^th century Britain imported 80% of its wheat consumption, 65% of its fruit and 40% of its meat.

 

High input farming

The huge increase in the area under crops and pasture in the last 3 centuries and the development of a world trade in food would not have been sufficient on their own to sustain the 7-fold increase in the world’s population in this period. This depended on a series of technological changes that radically transformed agriculture in the industrialised world into a high-input, high-energy business with much higher levels of output.

• Until the mid-19^th century there had been only a very slow increase in agricultural productivity across the world as a result of the accumulation of a series of small-scale improvements – improved rotations, new fodder crops, better drainage, new equipment and some new crops.
• In the 600 years before 1800 crop yields in Europe doubled as a result of these changes and the same happened in China with the rice crop between 1450 and 1800.
• The first major change came with the huge increase in fertilizer use, with the importation into Europe in the 1820s of guano from the huge artificial islands off the Pacific coast of Latin America.
• It became commercially feasible after the First World War but took up large amounts of energy to produce the artificial nitrogen fertilizers and it was not until the second half of the 20^th century that their use expanded dramatically.
• Overall the world’s use of artificial fertilizers rose from 360,000 tonnes in 1900 to 137 million tons in 2000 with a peak usage of 150 million tonnes in 1990.
• Much of the fertilizer was wasted. At least half of it simply ran off the soil into water courses where it caused numerous environmental problems.
• Excessive use of these fertilizers also reduces the uptake of key trace minerals in the soil, which can damage plant growth and lower nutritional levels.
• The massive use of fertilizers has had only a limited impact on crop yields. In western Europe fertilizer use rose 10-fold between 1910 and 2000 yet crop production only doubled.
• By the end of the 20^th century across the world it was clear that fertilizer use had reached its effective maximum – adding more to the soil no longer increased yields and merely increased other problems.
• In parallel with the increasing use of artificial fertilizers there was a rise in the mechanization of agriculture replacing some of the back-breaking labour of the previous thousands of years.
• The number of tractors in the world increased from 300,000 in 1920 to 26 million by the late 20^th century.
• In 1965 just 1% of the California tomato crop was picked by machines; within 3 years only 5% was picked by hand.
• One of the consequences of increased agricultural productivity and high levels of mechanization was the rapid decline in the agricultural labour force and an increase in the size of farms.
• As late as 1851 half of the British population was still rural and in 1920 half of the American labour force still worked on farms.
• By the late 20^th century in the industrialised world no more than 2% or 3% of the workforce were working on farms.
• In the United States there were 7 million farms in the 1930s but less than 3 million fifty years later when over half of all agricultural produce came from 5% of the farms.
• The average size of the American farm tripled in the 50 years after the mid-1930s and in the Soviet Union the average state farm covered over 40,000 hectares.
• Until the 20^th century traditional methods of raising domesticated animals were extensive and the numbers that could be supported were limited by the availability of pasture and fodder crops.
• In the 20^th century increasingly intensive, high-energy systems were introduced.

Instead of feeding outdoors on natural foods such as grass, animals were brought indoors and fed on artificial feeds. Chickens are kept in grossly over-crowded battery cages, cattle in small stalls and pigs chained to walls in sties small enough to ensure they cannot move. Animals which are herbivores are fed on a diet which includes a high percentage of dead animals, recycled manure, growth hormones and even newspaper and cement dust. In addition they are routinely given high levels of antibiotics to counter disease that would otherwise be rife in such conditions.

• Agricultural output in the industrialized world in the last 60 years has also been raised artificially by the use of huge subsidies.

• Across the industrialized world subsidies in various forms now amount to about $500 billion a year.
• The EU guarantees sugar producers a price of £423 a tonne against a world price of just over £100 a tonne.
• In the United States the government provided income support for rice farmers of $1.3 billion a year at the end of the 20^th century yet the total value of rice production was only $1.2 billion.
• In Japan government subsidies to farmers amount to 1.4% of GDP yet agriculture only contributes 1.1% of Japanese GDP.
• Cows in the United States and the European Union are each subsidized to the extent of $2.7 a day, which is twice the average income of a farmer in the developing world.
• At the same time India, the largest milk producer in the world, is forbidden by the World Trade Organisation from subsidizing milk production.

Overall modern industrialized agriculture is highly energy-inefficient. Although output is high this relies on huge inputs that consume large amounts of energy. Machines have to be made, and then consume fuel when being used. Huge sheds containing animals have to be heated and lit. Animal feeds have to be produced in factories. Huge quantities of artificial fertilizers, pesticides and herbicides have to be used and these require large amounts of energy to produce. Then the products of the farms have to be transported over large distances and stored. Overall agriculture in the United States now consumes more energy than it produces.

Agriculture in the developing world