It’s not easy to migrate away from Africa and it’s a matter of political willingness to accept “waves of refugees”.
Well, it’s happening in Europe already. The US is having immigration issues of its own as well.
When it comes to the issue of overpopulation we face the trend that birth rates go down. The problem moves in the right direction. As far as current trends go it’s unlikely that population will double.
As I said to Lumifer, birth rates are going down because of wealth, which is driven by technology. As you pointed out, though:
A US citizen ten times the amount of energy as a nigerian.
...wealth is also accompanied by increased resource demand which may cancel out the time that diminished population growth buys us.
Well, it’s happening in Europe already. The US is having immigration issues of its own as well.
As I said to Lumifer, birth rates are going down because of wealth, which is driven by technology. As you pointed out, though:
...wealth is also accompanied by increased resource demand which may cancel out the time that diminished population growth buys us.
By the way, the emphasis on Africa is misplaced. It might, as a continent, have the highest growth rates, but most populated countries are outside of Africa, and most of them have grown by more than 20% between 1990 and 2010.