We can see this graphically in age pyramids for individual countries
'Quality of life' for the 6-11 billion... what does that actually mean? We need ways to think about and assess distribution and inequality of the elements of 'quality', but what are they? We don't seem to be in danger of having to find out by direct personal experience, which is all the more reason to try to do so vicariously. One way to begin might be via a clever computer app that purports to allow you to Calculate your Ecological Footprint. Here's one summary:
Each organism uses resources from the ecosystem to exist. We express this essential requirement as an area of the planet that annually supplies these requirements each year and define this as the organism's ecological footprint. For humans, we can record the consumption data and convert it into an area that supplies these ecosystem resources that are annually appropriated by each person. This is an example of a "systems analysis" that is very helpful for us to understand the connections between our behavior and our dependency on the ecosystem. Our ecological footprint helps appreciate what we get for free from ecosystem services.They offer a link to Redefining Progress, which has (among other things) a page on Footprints of Nations. Science or Snake Oil?
In this class the Ecological Footprint is derived from household consumption, and expressed for an average per person. The analysis used is simplified to allow more convenient transformation of data ordinarily available to each of us into the resource base. You are encouraged to examine the analysis carefully, and identify as best you can how each activity draws from particular kinds of natural resources. Then, begin to manage the size and composition of your ecological footprint by modifying your actions. This is Natural Resource Management at the basic level for which you have considerable control.
World Bank distribution of income or consumption (data from the 1990s) and UNDP World Income Inequality Database and University of Texas Inequality Project (James Galbraith)
The Young Personís Guide to the Theil Index: Suggesting Intuitive Interpretations and Exploring Analytical Applications (UTIP No.14 --54 pages)