Demographic Transition

The aging trend is merely the tail end of the much larger demographic transition which has fundamentally shifted the historic demographic pattern from one that has endured for most of human existence to one that has accompanied the development of our modern societies.

In this transition, which began in earnest in the mid-18th century, life expectancy has increased from under 40 years to over 70 and the number of children per woman has decreased from 6 to near 2.

Achieving 70 years of age was a rare event in most previous human societies but is now expected as most developed countries approach a life expectancy of 80. Correspondingly, the preponderance of those under 15 has fallen from almost 40% to 20%.

The rapid population growth of the past 2 centuries has been due to the high birth rate being maintained while modern medicine and improved hygiene combined with vastly expanded oil based agricultural production to allow those born to live much longer.

Historically, populations have grown at a very slow rate and the explosion of the last 300 years is a singular even in human history. As societies have matured, the birth rate has fallen ending the phase of rapid growth for most developed countries. In fact, many have now achieved either a stable population or even one which is slightly declining.

This has resulted in an age structure which is unlike anything previously seen in human societies: one that features almost as many old people as young people.

The final stage in the demographic transition establishes the balance between young and old at levels much closer to parity as extensions in life expectancy flatten out.

This enormous demographic transition is not an endless trend but rather a pattern shift brought on by technology applied to food supply, social habits and medicine. Although over 300 years in the making, it is a singular event and requires society to transform in many ways to accommodate it rather than proceeding on the assumption that the transition process itself is the Anormal@ state.

Neither the aging trend nor the demographic transition are shifts that can be reversed. Understanding the nature of the changes and modifying our expectations of endless growth are the challenges which all countries will have to meet. Canada is fortunate that many advanced societies are decades ahead in this transition and are providing an excellent reference for the development of policies which will allow us to deal successfully with fundamental demographic changes.

Factoids on Aging

In hunter-gatherer societies, child births were spaced over 4 years apart. This was to allow the child to be at least partially mobile when the tribe migrated as only once child could be carried at a time. In agricultural societies which were stationary, childbirth spacing fell to two years.

Hunter-gather societies tended to be healthier due to their higher quality diets and had a greater life expectancy with many more people reaching 60 than was the case for agricultural societies. Women in agricultural societies typically gave birth to 6 children whereas women in hunter-gatherer societies had 4 children.