The average age of the population is advancing on a global scale. In order to respond to this dramatic change in the population structure, which humankind is experiencing for the first time, the United Nations will hold the Second World Assembly on Aging in Madrid in April. The First World Assembly on Aging was held in Vienna in the summer of 1982.

The U.N. estimates that the ratio of elderly people at least 65 years old to total world population will rise from 6.9 percent in 2000 to 14 percent in 2040 and 15.6 percent in 2050. The increase is particularly striking in developing countries; four of every five elderly people reside in a developing country. This fact will require a change in the conventional perception that the main problem for developing countries is population growth and that developed countries have the problem of aging.

The U.N. first began tackling the problem of aging in the latter half of the 1970s. At the first world assembly 20 years ago, the U.N. forecast that the world's elderly population would reach 600 million by the beginning of the 21st century. At that time, the ratio of elderly people in the world was 5.9 percent, and the phenomenon of aging in developing countries was not yet considered a problem.

In Japan the number of elderly had topped 10 million, and the graying of the population was proceeding at a rapid pace. It was not surprising, therefore, that Japan sent an 18-strong delegation to the Vienna assembly. The meeting, attended by 1,400 participants, including government representatives from 124 countries, lasted for 12 days and closed with the adoption of the International Action Plan on Aging, which was intended to serve as a guideline for national policies on the aging problem.

Premised on the recognition of aged people as a valuable human resource, the action plan contained recommendations on 48 issues in six areas (health, housing environment, family, social welfare, income security and employment and education) to enable older people to lead stable lives.

The problem is the extent to which national governments have been able to embody this international action plan in policies that affect the elderly members their societies. The U.N. has taken many steps to encourage speedy implementation of the recommendations. For example, in 1990 it decided that Oct. 1 would be the International Day of Older People. And it designated 1999 as the International Year of Older People, with the slogan of "building a society for all ages." The action plan also called for promotion of the U.N. Principles for Older People, which proclaim independence, participation, care, self-fulfillment and dignity for older people.

The result? Because of varying political and economic conditions in each country amid differences in the speed, scale and effects of aging and other factors, it is difficult even for the U.N. to gain an understanding of the actual situation in each country. Hence the decision was made to hold another world assembly in Madrid. Twenty years after the adoption of the international action plan, the World Body wants to examine and evaluate the plan's implementation, search for a new strategy for tackling the problem of aging on a global scale and formulate a revised action plan.

Compared with the first world assembly -- when the need to take countermeasures for aging was considered a problem of the developed nations -- the background has clearly changed. Because of declining birthrates, the speed and scale of aging are now conspicuous in developing countries as well.

Preparations for the assembly, led by the U.N. and the Spanish government, are proceeding steadily. A meeting of government representatives will be the centerpiece, but there will also be a forum for nongovernmental organizations.

According to the U.N. preparatory committee that is discussing the draft of a revised action plan, proposals to be covered include such issues as participation by older people in the societal decision-making process, solidarity among generations, elimination of abuse and violence against older people and the promotion of lifelong programs aimed at improving health and welfare in old age.

Japan, whose population is aging the fastest, has an important role to play at this assembly. The Japanese government intends to introduce its "outline of countermeasures for aged society," which it has formulated as a medium- and long-term guideline, and to play an active role in compiling the revised U.N. action plan. At the assembly, Japan should frankly speak about both successes and failures in tackling the problem of an aging population. It is precisely by discussing its experiences and offering policy suggestions that Japan can make a useful contribution to developing countries.