Migrants can help to fill the gaps in Asia's greying societies

The low fertility rates and fast-ageing populations of Asia's developed economies are barely noticeable to those living in them. Facts and figures mean little to people working long hours to pay mortgages and school fees. But one recent doomsday scenario has certainly grabbed attention - South Korean researchers predicted that unless dramatic changes take place, the country's last citizen will die in around 2750. With Hong Kong greying even faster, there is every reason for family-friendly policies and flexible approaches to labour and immigration to be priorities.

South Korean women have just 1.19 children during their lifetime, well below the 2.0 rate needed to replace the population. The recent study by the National Assembly Research Service in Seoul determined that if the level continued, the population would shrink from the present 50 million to 10 million in 2136. That would be a nightmare: vibrant, working-age populations are crucial for growth and development. The majority of people have to be wage earners so that the tax base can be expanded to fund schools for the young and pensions and health care for the elderly.

Hong Kong, with a fertility rate of about 1.0, is even worse off; unless attitudes to childbirth and immigration change, Hongkongers will die out in 25 generations. Singapore, Macau, Taiwan and Japan have the same worries, although the trend is global, with declining birth rates in 76 nations, or about half the world's population. China's one-child policy has artificially given it a similar problem. The Asian countries that are least affected are India, Indonesia, the Philippines and Sri Lanka.

High costs of living and a lack of job security deter families from wanting children. So, too, do small flats, crowded streets, pollution and a shortage of places for recreation. Smaller families also have benefits for societies. Education standards improve, women have more rights and freedoms, and the middle class expands in size.

Whatever the benefits, though, a population that is too old is not sustainable. Governments have found that generous family allowances are not enough to convince women to have more children. Improving living conditions helps. But the most viable solution lies in policies that bring in workers and attract migrants. Such approaches have to be carried out sensitively; there will always be concerns about a society's identity, threats to wages, increased crime and pressure on social welfare.