Population Crises and Population Cycles

The civilisation of China has always depended on irrigation and flood control. The first region developed was the easily worked loess area of the Upper Yellow River, growing wheat and millet; with greater mastery of flood control, cultivation of these crops was extended to the Lower Yellow River, more productive thanks to its silt but liable to serious flooding; and finally the rice region of the Yangtze River was developed, the most productive area of all. But the resulting advances in food production were always accompanied by excessive growth of population, leading to a succession of crises and cycles.

The first overpopulation crisis of which we have detailed knowledge occurred in the later 1st millennium BC. In former times, wrote Han Fei-Tzu (died 233 BC), "there were few people and plenty of supplies, and therefore the people did not quarrel ... But nowadays people do not consider a family of five children as large, and, each child having again five children, before the death of the grandfather, there may be twenty-five grandchildren. The result is that there are many people and few supplies ... so the people fall to quarrelling, and ... one does not get away from disorder." China was then composed of many little states, each busy completing the water control system within its own borders, and disputing with other states using the same rivers. Thus the state of Ch’i built an embankment on the Yellow River which had the effect of flooding the states of Chao and Wei, who built a counter-embankment to return the compliment.

The wars between the states ended in the unification of the Yellow River and the Lower Yangtze by the state of Ch’in, which controlled the loess area, forming what has been called a water-shed empire. Like similar empires elsewhere (the Assyrians, the Inca), the Ch’in Empire was a horrific military tyranny. When the wars, with their huge death-rates, were over, the first Emperor used his enormous army to build the Great Wall, a Stone Curtain designed to keep his subjects from straying out of his reach into the Central Asian steppe, where climate and terrain favoured the development of a nomad herding culture. However, no people could long tolerate a regime in which everything but agriculture and military training was forbidden, where art and love were capital offences, and where anyone failing to denounce a friend for law-breaking was sawn in half. In 202 BC the Ch’in were finally replaced by the first great Chinese dynasty, the Han, ruling through a relatively humane and flexible bureaucracy, selected by public examinations. These were open to all in theory, and in some periods even in practice, but few people had time to learn written Chinese except the sons of the land-owning gentry, who fused with the bureaucracy into one class, the mandarins. This system survived through all the Chinese Imperial dynasties.

The population cycles of China since the Ch’in are shown in Table 1. The third column shows increases in food production as various regions were fully developed and new crops introduced. The numbers of water control works are minimum figures, but they give a fair picture of the differences between earlier and later periods, and between relief and crisis periods, when water control activities increased more slowly or even decreased. Absolute population figures shown cannot be accurate, but from the fourteenth century onwards they are fairly reliable, and there is no doubt (even in earlier periods when no figures are given) about the enormous increase in population resulting from the successive advances in food production, or about the huge fluctuations accompanying the crises.

When the Han dynasty finally collapsed, in AD 220, China was long divided between the Northern plains, the Lower Yangtze and a new economic area, the Szechuan plateau. Then the Sui dynasty, almost as brutal and short-lived as the Ch’in, completed the linking of the Yangtze and the Yellow River by the Grand Canal. The grain wealth of the rice region could now be brought to a capital in the North, supplying armies that could dominate the rest of China. But, in every population crisis, China fell apart into its component regions, and even smaller fractions, ruled by numerous lesser dynasties not shown in Table 1. Besides famines, epidemics and appalling civil wars, China suffered during the population crises from incursions of nomad chieftains from across the Central Asian borders, who often founded the Chinese dynasties, notably the Yuan (Mongol) and Ch’ing (Manchu) dynasties, whose conquests were particularly destructive. By the dreadful crisis of the twentieth century, the nomads had been subdued, but China suffered instead from her own brutal war-lords, European exploitation, and Japanese conquest.

In 1949, the People’s Republic brought peace to China, amidst popular enthusiasm like that which greeted the accession of the great national dynasties of the Han and Ming. But the new government delayed introducing birth control, and another crisis ensued, the ‘Cultural Revolution’, which nearly destroyed Chinese civilisation and caused massive environmental damage. It remains to be seen whether China’s new birth control policy will reduce the population in time to avert another crisis, and bring to an end the ‘cycles of Cathay’.