How to fit 8.5 billion people on the globe

EVERY year the world adds 90 million people to its population - equivalent, say, to another Mexico. We are not particularly aware of this in Britain because the additional people are not born here, or in the industrial world at all. Some 95 per cent of the population growth is in the developing countries, with the result that the world is splitting into two entities: an old rich world and a young poor one, with the former accounting for an ever smaller proportion of world population. In 1950 a third of humankind, then numbering 2.5 billion, lived in the industrial world. Now, with a total of 5.5 billion, it is below a quarter. By 2025, when world population will be around 8.5 billion, it will be less than one fifth.

New estimates of the world population in 2025, published today by the Population Reference Bureau in Washington, show how the pecking order of countries will change. The big two, China and India, remain in those positions, but Japan and Germany slip, and the UK, Italy and France, at present 18, 19, and 20, go down to 25, 30, and 27. By contrast a country like Ethiopia, which at present has fewer people than Britain, becomes a giant with nearly 141 million, while Nigeria becomes the sixth largest country in the world, with nearly a quarter of a billion.

Faced with this population explosion in places where the diet is already inadequate, the inevitable question is: can the world feed these numbers? The vast amount of work done on this issue suggests it can, though it will be tight.

Rather less thought has gone into the political and social consequences. Politically, it was understandable (if a little shaming) to have the developed countries bossing the rest when they accounted for only 30 per cent of world population; it becomes very hard to justify when they account for perhaps only 18 per cent, as they will in 2025. Socially, an old rich world and a young poor one is an explosive mix.

Imagine a Europe that feels like Bournemouth - a lot of older people, most quite comfortably off, with, inevitably, the attitudes and values of that age and income group. Imagine an Africa that feels like the outskirts of Cairo - one that has become much more urban, even younger, sadly perhaps even poorer, and able to watch a soap opera version of the rich world through satellite televisions on every street corner. On the one hand, there will be concern and sometimes fear; on the other, there will be envy, and perhaps anger.

With the best will in the world, some tension is bound to result. Yet it is in the interests of both sides that they should defuse these tensions. In theory, the availability of vigorous, young and inexpensive labour in the developing world could help the industrial countries offset the effects of what might otherwise be a debilitating population decline. In theory, too, the technology of the industrial world could be used to help to feed and house these people, with the least possible damage to the environment. But how?

Migration cannot help, for the numbers simply do not add up. The only industrial country taking in large numbers of immigrants is the US. In 1992 it received more than 800,000, the highest number since 1914. But, even running at full tilt, the US took in the equivalent of only 1 per cent of the population increase of the developing world. And even if other parts of the industrial world were to take in immigrants on a similar scale (which would be very difficult), total migration would account for less than 4 per cent of population increase. There will be great pressure for migration - southern Europe is already feeling that from north Africa - but the numbers are such that it cannot make a material contribution to solving the problem.

There really is only one way forward. It is for the industrial countries to move some of their more labour-intensive activities to the developing world. This means buying more goods with a high labour content, such as textiles, from these countries. It means investing in assembly plants for goods designed and marketed in the West. It means using the fact that telecommunications time is incredibly cheap to have clerical jobs done abroad.

Where there is an economic rationale, the market system can be expected to respond, and in merchandise trade it has. Our garments often come from places such as Sri Lanka, our trainers from South Korea and our phones from China. But the possibilities of telecommunications will help to extend the trade to services. Two of the world's airline computer reservation systems are run from Barbados. There is no reason why they shouldn't: the country has well-educated people with English as their mother tongue.

The fact that many developing countries are in different time zones can be an advantage, making possible a 24- hour service without people having to work unsocial hours. A London law firm needing a complex set of documents typeset overnight could have them done in Bombay.

Using the developing countries' cheaper labour does not solve the population explosion. Whatever the industrial world does will only have a marginal impact. But by transferring both money and know- how, the industrial world can show that it is on the right side; the knowledge transfer should also help developing countries to avoid some of the errors - environmental and social - that have been made by the West. The burghers of Bournemouth should then sleep a little more soundly, and the millions in the shanty towns have a slightly higher quality of life.

----------------------------------------------------------------- World's countries ranked by population size ----------------------------------------------------------------- 1993 Population 2025 Population (1,000s) (1,000s) 1 China. . . . . . . .1,178,526 1 China . . . . . . . . .1,546,301 2 India. . . . . . . . .897,443 2 India . . . . . . . . .1,379,556 3 United States. . . . .258,328 3 United States . . . . . .334,716 4 Indonesia. . . . . . .187,638 4 Indonesia . . . . . . . .278,170 5 Brazil . . . . . . . .151,989 5 Pakistan . . . . . . . . 275,108 6 Russia . . . . . . . .149,001 6 Nigeria . . . . . . . . .246,030 7 Japan. . . . . . . . .124,767 7 Bangladesh . . . . . . . 211,224 8 Pakistan . . . . . . .122,398 8 Brazil . . . . . . . . . 205,250 9 Bangladesh . . . . . .113,882 9 Iran . . . . . . . . . . 161,913 10 Nigeria . . . . . . . 95,060 10 Russia . . . . . . . . . 152,280 11 Mexico. . . . . . . . 89,998 11 Ethiopia . . . . . . . . 140,800 12 Germany . . . . . . . 81,064 12 Mexico . . . . . . . . . 137,483 13 Vietnam . . . . . . . 71,788 13 Japan . . . . . . . . . .125,806 14 Philippines . . . . . 64,648 14 Vietnam . . . . . . . . .107,225 15 Iran. . . . . . . . . 62,847 15 Egypt . . . . . . . . . .104,607 16 Turkey. . . . . . . . 60,705 16 Zaire . . . . . . . . . .104,530 17 Egypt . . . . . . . . 58,292 17 Philippines . . . . . . .100,845 18 United Kingdom . . . .58,030 18 Turkey . . . . . . . . . .98,744 19 Italy. . . . . . . . .57,837 19 Thailand . . . . . . . . .76,403 20 France . . . . . . . .57,678 20 Germany . . . . . . . . . 73,201 ----------------------------------------------------------------- Source: Population Reference Bureau's 1993 World Population Data Sheet -----------------------------------------------------------------