Duration of life and its social implications the world’s population is about to reach a landmark of huge social and economic importance, when the proportion of the global population over 65 outnumbers children under 5 for the first time. a new report by the us census bureau shows a , with enormous consequences for both rich and poor nations. the rate of growth will shoot up in the next couple of years. the в a combination of the high birth rates after the second world war and more recent improvements in health that are bringing down death rates at older ages. separate un forecasts predict that the global population will be more than nine billion by 2050. the us census bureau was the first to sound the с . its latest forecasts warn governments and international bodies that this change in population structure will bring widespread challenges at every level of human organization, starting with the structure of the family, which will be transformed as people live longer. this will in turn place new burdens on careers and social services providers, d for health services and pensions systems. “people are living longer and, in some parts of the world, healthier lives, ” the authors conclude. “this represents one of the greatest achievements of the last century but also a significant challenge e population.” ageing will put pressure on societies at all levels. one way of measuring that is to look at the older dependency ratio, f that must be supported by them. the odr is the number of people aged 65 and over for every 100 people aged 20 to 64. it varies widely, from just six in kenya to 33 in italy and japan. the uk has an odr of 26, and the us has 21. 1. which recently replaced italy as the world’s oldest major country 2. alarm about these changes 3. a huge shift towards an ageing population 4. change is due to 5. while patterns of work and retirement will have huge implications 6. which shows the balance between working-age people and the older 7. as proportions of older people increase in most countries