Book contents
- Frontmatter
- Contents
- List of sources for illustrations
- Preface
- 1 Disease patterns in human biohistory
- 2 Human biology: the Pleistocene inheritance
- 3 Adapting to diversity: climate, food and infection
- 4 Infectious disease: humans and microbes coevolving
- 5 The Third Horseman: food, farming and famines
- 6 The industrial era: the Fifth Horseman?
- 7 Longer lives and lower birth rates
- 8 Modern affluence: lands of milk and honey
- 9 Cities, social environments and synapses
- 10 Global environmental change: overstepping limits
- 11 Health and disease: an ecological perspective
- 12 Footprints to the future: treading less heavily
- Notes
- Index
7 - Longer lives and lower birth rates
Published online by Cambridge University Press: 05 March 2012
- Frontmatter
- Contents
- List of sources for illustrations
- Preface
- 1 Disease patterns in human biohistory
- 2 Human biology: the Pleistocene inheritance
- 3 Adapting to diversity: climate, food and infection
- 4 Infectious disease: humans and microbes coevolving
- 5 The Third Horseman: food, farming and famines
- 6 The industrial era: the Fifth Horseman?
- 7 Longer lives and lower birth rates
- 8 Modern affluence: lands of milk and honey
- 9 Cities, social environments and synapses
- 10 Global environmental change: overstepping limits
- 11 Health and disease: an ecological perspective
- 12 Footprints to the future: treading less heavily
- Notes
- Index
Summary
Humankind has just lived through a demographically phenomenal century. During the twentieth century the following four things happened: human numbers increased almost fourfold, the proportion of people living in cities increased fivefold from approximately 10% to 50%, world average life expectancy doubled and, during the second half of the century, birth rates approximately halved. We are now heading towards a world of large, urban and long-lived–indeed, elderly and therefore dementia-prone–populations. The consequences of these various demographic changes for patterns of health and disease have already been great. In future they will be equally great.
In 1999 total human numbers passed 6 billion. Another 750 million will be added during the first decade of the twenty-first century. The global total is likely to reach 8–9 billion by 2050. Beyond that the projections are, of course, less certain. Although most demographers forecast a plateauing at around 9–10 billion later in the twenty-first century, we could yet be surprised by a much higher or lower figure. If it is the latter, one hopes that it will be because of reduced fertility, not increased mortality. Recent experiences in the wake of the socioeconomic collapse in post-communist Russia and the now catastrophic HIV/AIDS epidemic in Africa remind us that increased death rates remain possible.
Our passage through these demographic and social transformations over the past 150 years has entailed changes in contraception, human sexuality and family structures.
- Type
- Chapter
- Information
- Human Frontiers, Environments and DiseasePast Patterns, Uncertain Futures, pp. 185 - 219Publisher: Cambridge University PressPrint publication year: 2001