We are Forerunners. Guardians of all that exists. The roots of the Galaxy have grown deep under our careful tending. Where there is life, the wisdom of our countless generations has saturated the soil. Our strength is a luminous sun, towards which all intelligence blossoms... And the impervious shelter beneath which it has prospered.
Basically, by 2100, Asians and Africans will dominate the world's population. Unfortunately, there isn't really much of a breakdown as to which Asians and Africans will be doing the dominating.
Given the current population trends of the world, we can hazard some rough guesses as to which nations will grow and which ones will decline.
First, China and Japan and most of the Far East is, basically, screwed. When a population pyramid inverts, which is exactly what China's will do, the end results won't be pretty. Such a social structure places tremendous strain on all aspects of a nation. Old people are founts of wisdom and grandfatherly joys and all of that good stuff, but the cold hard fact is that old people also aren't terribly productive relative to, well, people my age. Their time on this good green Earth is mostly done; they're not going to be building the future, we are. They are essentially consuming the results of our labours.
(I'm not saying I dislike old people- even though I kind of do, since I dislike pretty much everyone by default, being the cranky misanthropic bastard that I am. I'm just stating the facts.)
There is nothing particularly wrong with this; being Asian, I rather agree with the view that if your parents took good care of you as you were growing up, you owe it to them to return the favour when they need you. But it does impose certain uncomfortable economic realities upon those providing the care.
Second, America and Europe are even more screwed- Europe more than America. It's well-known by now that the nominally Christian West is in long-term demographic decline, and has been for decades; what various prognosticators seem to keep forgetting is that the West is in demographic decline specifically because it turned its back on those very same Christian values. If you actually look at those horrible, terrible, no good, very bad "fundamentalist Christian orthodoxy" types that liberals love to wet their beds over, that segment of the population is doing just fine. The same is true of Orthodox Jews, who- for better or worse- are outbreeding their secular counterparts by a rather considerable distance.
Third, and by far most important for the future, Africa, and specifically sub-Saharan Africa, will be sprouting like mushrooms.
This is NOT a good omen.
Yes, I know, it's horribly RAAAACISS to point out these things in polite society these days, but let's call a spade a shovel and be clear about what the growth of Africa means for the rest of us.
Ever been to sub-Saharan Africa? I haven't, so I have no idea whether it's really a nice place or not. Judging by the numbers of Africans who seem to want to get the frack OUT of there, though, I think we can get a very rough approximation of what it's like to live there. Given that rough approximation, I do have to wonder about just how viable that region is, politically, economically, and so on.
Moreover, we can draw certain conclusions just by looking at the track record of various African governments and institutions to see whether having 4 billion Africans in the world would be a Good Thing.
The evidence tells us that things don't look great.
Africa, in general, has become virtually synonymous with "complete and utter failure". It's not like we can blame colonialism for what ails Africa, either- the Africans have been free to murder each other with impunity for 40 years or more, and they seem to show no diminution whatsoever in their enthusiasm for doing just that. Governments come and go in that part of the world like the tides; tinpot dictators, corrupt bureaucrats, and fat-cat oligarchs stealing from their people are all depressingly common stories when it comes to Africa.
Even the occasional success stories, like Botswana and Lesotho, are marred by the very nasty realities of rampant HIV infection rates.
Add to that the fact that, wherever they have gone, Africans have generally shown a trend towards dyscivic behaviour. (Again, this is a generalisation. No doubt some of you know and are on good terms with Africans who are exemplars of morally upstanding and righteous behaviour.) When we observe African immigrants in Minnesota effectively trying to recreate Mogadishu and Monrovia, or the way that the Black Undertow has caused white (and Asian) flight away from the cities and into the suburbs, we are forced to come to terms with very uncomfortable realities about racial assimilation and tribal factionalism.
Put all of these things together and you may well have to confront a very bleak future.
I could be entirely wrong, of course, and everything could come up roses. It could very well happen that sub-Saharan Africa suddenly becomes a beacon of liberty, religion, civilisation, and hope. It could be that the world stops trying to hand aid to poor Africans in the completely misguided hope that it will do anything other than keep them dependent and starving. It could be that somehow the tribalism and parochialism that keeps Africa poor and hungry goes away due to some unforeseen force. And it could be that Africa will become something other than a seemingly cursed continent, home of disease and squalor and misery.
Of course, in order to draw these conclusions, you would have to ignore virtually everything that we know today about Africa.