Half a century ago, the world was warned of the imminent explosion of "the population bomb." There were fears that humanity would suffer mass starvation. And that societies would plunge into turmoil - because of overpopulation.
At that time, Asia was considered to be at the core of the population problem. The average woman in Asia could expect to bear five children in her life time. The region's population was projected to double within 33 years.
Many countries responded by embarking on programmes to control population growth. The landmark 1994 International Conference on Population and Development (ICPD), attended by 179 governments, shifted the discourse on "population control" to people-centred development.
The ICPD Programme of Action established, for the first time, inseparable linkages between population and development policies, with a clear focus on sexual and reproductive health from the standpoint of human rights - in particular the rights of women and families to decide freely whether and when to have children.
The probability of every child surviving to adulthood was greatly increased. Families acquired better knowledge of sexual and reproductive health. Many more were given the means to make informed decisions about their fertility.
The Asia-Pacific region can be proud of its successes: an average woman today has around two children instead of five. Life expectancy has increased dramatically. Fifty years ago, the average person could expect to live until the age of 45. Today a woman can expect to live to the age of 72 and a man to 68. Almost as many girls as boys enter primary school.
But success comes with new challenges. The concern today is not just about population numbers. Rather, it is about the complex interlinkages between population and development.
Putting people first to build better lives must remain the focus of efforts to address the population and development challenges that the Asia-Pacific region faces.
Increased life expectancy and lower fertility rates have resulted in rapid population ageing in the region that is unprecedented in human history. Some countries are at risk of becoming old before they become rich.
The population of older persons will triple by 2050 to reach 1.2 billion. In East Asia, one in three persons will be aged 60 or older. Furthermore, by 2050, there will only be 3.5 working persons to support one older person, as compared with 10 working persons today. There is thus an urgent need for the region to prepare for ageing societies.
While the opportunity for the demographic dividend has passed in some countries, in others there is still an opportunity to harness its potential. In South Asia, around half of the population is still below the age of 25. With the appropriate mix of policies, including job-led growth and effective school-to-work transition, it will be possible to reap the youth dividend.
On issues of sexual and reproductive health and rights, great strides have been made in strengthening policy. Yet programme implementation is lagging, particularly in targeting the most sexually active population group, namely youth.
Lack of information concerning sexual and reproductive health and limited access to related services are contributing to unintended pregnancies and unsafe abortions. These gaps are also exposing millions to the risk of HIV, in particular key populations at risk, including people who inject drugs, people who buy and sell sex, men who have sex with men and transgender people. This means that comprehensive sexuality education and increased access to a range of contraceptives must be made a priority.
Furthermore, sexual and reproductive health programmes must also reach childless married women, unmarried women and girls, as also men and boys, as part of an integrated public health system that combines curative, preventive and health promotion services.
Despite overall progress on maternal health, in some countries the number of women dying in childbirth still remains stubbornly high. There are parts of the region where one in 200 mothers dies giving birth.
Asian and Pacific nations must do better in incorporating rights-based approaches to addressing population dynamics in their long-term plans for inclusive and sustainable development, including the impact of climate change.
And most of all, the response to the region's challenges must be grounded in a commitment to addressing the unmet needs of women and all other groups that remain excluded from the development process.
How do we collectively tackle these new and persistent challenges? That question will be answered at the Sixth Asian and Pacific Population Conference (APPC), which ESCAP is organizing with UNFPA this week in Bangkok. This Conference is part of, and will contribute to, the global ICPD 20-year review mandated by the United Nations.
More than 400 representatives, including ministers, from over 45 countries and stakeholders from civil society will gather at this Conference. Meeting 50 years after the first APPC in 1963, they will seek fresh solutions to the region's population and development challenges.
The outcome of the Conference will shape population and development policies for the future we want.
As Asia-Pacific takes its place on the world stage, our governments have the means and the responsibility to build better lives for the region's 4.3 billion people. There is greater hope that the rapid population and development transformation will nurture the promise of a future that will be brighter than what had been predicted half a century ago.
Dr. Noeleen Heyzer is Under-Secretary-General of the United Nations and Executive Secretary of the Economic and Social Commission for Asia and the Pacific (ESCAP). Dr. Babatunde Osotimehin is Under-Secretary-General and Executive Director of UNFPA, the United Nations Population Fund.