The Orange Loops
From the rise of civilisation, up to the present time we have seen, in average global terms, an increase in human health and wellbeing. Of course there is huge variability across the world and setbacks at various times, but this scenario more or less describes human progress to date.
In turn higher levels of wellbeing have led to higher levels of social cohesion and more equality (Loop R4). Many will contest this relationship but if you wish you can replace cohesion and equality with any other term that represents cooperation between people.
The effect of living standards on global population is changing. Over human history rising living standards have increased birth rates and reduced death rates, and have accordingly led to higher population levels. That would indicate a positive relationship between wellbeing and population, and that has been the case in the past (Loop R1). However we are now seeing what the demographers refer to as a demographic transition. As living standards rise in developing countries the net population growth rate (births minus deaths) is dropping, as it already has in much of the developed world. This is significantly a function of increasing gender equality, essentially the ability of women to control their own fertility. Accordingly in the modern era, the relationship between population and wellbeing is reversed – higher living standards will tend to reduce population, hence the negative sign in Loop B3.
Evidence for the demographic transition can be seen in reduced rate of population increase since the 1970s.
Greater levels of equality will be needed to realise the full global demographic transition. In recent decades the rise in living standards has resulted in greater levels of inequality as identified in the recent book by the French economist Thomas Piketty; Capital in the Twenty First Century. His work shows that wealth inequality has been trending upwards in the developed world since the 1800s save for a period in the first part of the twentieth century due to wars and the depression.
Higher living standards also improve human wellbeing and equality, which promote the demographic transition (Loop B4) and enhance the effect of Loop B3.
However these loops are offset by Loop R3. If higher living standards in the more rapidly growing developing world increase average global inequality, they will also suppress the demographic transition which is a prerequisite for stabilising population. This results in a reinforcing loop linking living standards and population via equality and the demographic transition (Loop R3).