Thursday, 20 March 2008
Life Expectancy Revisited.
A friend just asked me if I had any data on the evolution of increasing human life expectancy.
‘Afraid not’ I said, and explained that expanding human life-expectancy has little to do with evolution at present, at least in the Darwinian sense. Genetically, and therefore anatomically speaking, humans (homo-sapiens) haven’t changed for about 130,000 years (modern humans appear in the fossil record in Africa about 130,000 B.C.).
But I do have data on the average human life expectancy which has increased as a result of improvements in technological culture.
The reason is that cultural developments operate many orders of magnitude faster than genetic evolution. Advances in medicine, diet, and labour productivity have happened in the blink of an eye, and have had dramatic impact in life spans.
Here’s the data:
Average Life Expectancy (Years)
Cro-Magnon Era: 18
Ancient Egypt: 25
1400 Europe: 30
1800 Europe: 37
1900 USA/Europe: 48
2008 USA/Europe/Japan: 79
If this exponential growth curve continues for even as little as the next 20 years, average life expectancy in the developed west will hit 98 by c.2030.
But, as my blog post of Tuesday, 6 November 2007 reports (blogsearch: 'de grey'), even this forecast is ultra-conservative.