Towards a world of 2-6 billion well-educated and therefore healthy and wealthy people (Editorial)

In times of economic crisis and increasing food insecurity coupled with continued rapid population growth in the poor countries, as well as the prospect of dramatic consequences of climate change around the globe, the future looks rather bleak to many people. Hence the title of this editorial may sound oddly optimistic. But there is very good news hidden in the statistics of recent education trends around the world which imply significant future improvements in human capital and, as a consequence, likely improvements in global health and material well-being. In what follows I shall try to summarize what new statistical and demographic models applied to the long-term trends of population imply for our common future. Demographic trends can be forecast into the longer-term future with lower uncertainty than many other social and economic trends, but they are less predictable than most geobiophysical trends. The reason lies in the length of the human lifespan of currently around 70 years on the global average. If we know how many 10-year-old girls are alive today, we have a very good basis for projecting how many 60-year-old women will be alive 50 years from now. On the global level the only uncertainty lies in unexpected future changes in mortality. For national and regional projections, uncertainties about future migration matter. The same is true for projecting certain stable properties of people: knowing how many 30-year-old men have been to college today is a good basis for projecting how many 60-year-old men will have a college education in 2040. In doing so we also must consider the fact that generally more highly educated people have lower mortality rates. Whereas the 'stocks' are inert and rather easy to project, the projection uncertainties come from assumptions on the 'flows'. For population projections it is the uncertainty about future trends in the birth rates that has the greatest effect on long-term population size. In the case of human capital projections, the future transition rates from lower to higher educational status are the main source of uncertainty...