Answering the Comments

In response to my post criticizing Romer's take on why Africa is poor below, commenter "Anonymous" writes:

Why couldn't they just buy agriculture on the world market and produce something else? A little comparative advantage. The reason is that Romer is right, they lack the necessary institutions to make use of all the first worlds technological innovations.

The legal institutions and cultural norms of the third world are what hold them down. Not agricultural tech and not their geography.

I was a bit flippant in my response -- but the main point is that if you go to really poor countries today, it is impossible not to notice obvious low human capital deficiencies in the populace, such as those stemming from poor nutrition. If you didn't have enough to eat growing up, your parents also probably did not have the resources to give you a proper education, and you are not likely to be as productive, even working on an assembly line, as someone from a rich country who always had enough to eat and has had enough schooling to at least be able to read, write, and do simple arithmetic.

The point is you need an agricultural revolution first. OK, Britain didn't have that before the IR, but Britain did have really high death rates and low birth rates, and later, access to American grain, which all had the same effect as an Agricultural Revolution...

And poor countries do import lots of grain from temperate countries, but if you are a desperately poor country with nutrition issues, it's not so easy to produce enough manufactures to feed yourselves on Kobe beef, French cheeses, and Omaha steaks...