An estimated 100 million people - almost double the population of Britain - have already become international migrants, says a report published yesterday by the UN's Population Fund. Almost 2 per cent of the world's population lives outside its country of birth.
The movement of people across borders and from rural areas to the booming 'mega cities' of the Third World now strains both industrialised and developing countries. Some of the biggest Third World cities are set to double in size in a dozen years, the UN says.
'The only effective means to reduce migration pressures over the long term are to slow population growth; to stimulate economic growth and job creation at home, and promote the development of the individual and family as the basic economic and social unit,' it concludes.
World population now stands at 5.57 billion and is projected to rise to 6.25 billion by the year 2000 and 8.5 billion by 2050. The UN warns: 'World population may not stabilise until 2150, at a projected level of 11.6 billion.'
These figures obscure a much faster growth rate in some parts of the world. In Africa today's population of 700 million is expected to more than double to reach 1.6 billion by 2025.
'Forty years ago, developing countries accounted for 77 per cent of the world population growth; today the proportion approaches 95 per cent. This growing imbalance is among the major contributing factors to international migration,' the UN says.
Half the people who leave their homes today are women. 'The evidence strongly suggests that, in combination with poverty, high fertility itself is a spur for female migration. Studies in Asia and Latin America have found that women who migrate typically come from larger than average families, an imbalance that is even more pronounced among families that have no land rights.'
UN Population Fund: The State of the World Population 1993.