Joergen Oerstroem Moeller's provocative essay challenges us to think seriously about the future. The world in 2050 is one that few have yet given serious consideration to, even though a great many of the people already on the planet are likely to live in it.

His two central theses--the rise of Africa, and the need for a fundamental shift in "paradigms" if economic development is to be sustained--both deserve careful thought. Africa's demographic rise in the decades ahead is a virtual certainty--barring only a catastrophe of Biblical proportion. Fertility is the major driver, in sub-Saharan Africa the 5.1 births per woman estimated by the UN Population Division are nearly twice as high as the global average. Even if these birth rates were to fall precipitously, sub-Saharan Africa's absolute population along with its share of global population, are set to rise robustly for a generation or more.

But do these demographic trends mean the sub-Saharan region will emerge as a global economic force? We can hope so, as prosperity in Africa will benefit not only the region itself. This bright future, however, is hardly a "given". Sub-Saharan Africa's economic performance over the past two generations has been dismal; it has been the epicentre of prolonged economic failure in an otherwise increasingly prosperous modern world economy. Some estimates suggest that real (PPP-adjusted) GDP in the sub-Sahara was lower in 2007, the year before the global economic crisis broke, was lower than it had been in 1974.

The sub-Saharan region will not be able to play the economic role Oerstroem Moeller envisions unless there is a complete turnaround in its economic performance. This doesn't just require dramatic improvements in health and education but fundamental chances in governance, none of which can be taken for granted. An alternative future for 2050, a much more populous Africa, but one in which desperate poverty, stagnant living standards and political instability still prevail, is much less pleasant to contemplate, especially for neighbouring Europe. It's an eventuality that must be borne in mind.

As for a shift to a new global development paradigm that would be far less dependent for growth on natural resources, I believe we have reason to be cautiously optimistic. There is considerable evidence that exactly this paradigm shift is already under way around the world, although perhaps less rapidly than some would want. Over the past century, worldwide economic growth has in overall terms become progressively less resource-intensive. Instead, economic development has relied more and more on human resources thanks to advances in health, education and scientific and technical knowledge.

Prof. Oerstroem Moeller doesn't mention one critical aspect of the global demographic outlook for 2050, and that's population ageing. Even more certain than the fall-off in human numbers after 2050 is the greying of the global population over the next 40 years, thanks both to greater longevity and to lower fertility levels. UN projections put the world's medium age in 2050 at over 38 years--about the same as Europe's in 2005--while Europe's median age will be close to 50 years, and in some countries even more. Sustaining improvements in living standards with these elderly populations will be a central challenge, so once again human-centered policies on health, education, innovation and knowledge production will be key. It is not too soon to start thinking about this "paradigm shift" too.

Nicholas Eberstadt is the Henry Wendt Scholar in Political Economy at AEI.

Photo Credit: iStockphoto/Peeter Viisimaa