二十一世纪的老龄化：庆祝和挑战 Foreword Population ageing is a major trend with global implications. With one in nine persons in the world aged 60 years or over， projected to increase to one in five by 2050， population ageing is a phenomenon that we can no longer ignore. Increasing longevity is one of humanity's greatest achievements. Indeed， population ageing is cause for celebration. The opportunities that this presents are as endless as the contributions that a socially and economically active， secure and healthy ageing population can bring to society. Opportunities come with challenges， however. Population ageing presents social， economic and cultural challenges to individuals， families， societies and the global community. It is how we choose to address the challenges and maximize the opportunities of a growing older population that will determine the future of humankind. This report， our contribution to the Madrid+10 review and appraisal process， takes stock of progress since the adoption of the Madrid International Plan of Action on Ageing in 2002. Ageing in the Twenty-First Century： A Celebration and A Challenge is based on an assessment of progress since the Second World Assembly on Ageing in 2002 in the three priority areas identified in Madrid： development， health and well-being， and enabling and supportive environments. 【更多详情，请下载：二十一世纪的老龄化：庆祝和挑战】