It seems that there are a few issues:
1) The current distribution of wealth fits the latitude hypothesis
pretty well. I don't think that anybody is really disputing this
point.
2) The real question is whether the current distribution of wealth is
typical or not. If you did the same study 1000 AD, would you get the same
picture? If not, then are just observing some special situation?
3) I think that if you did the same regression 1000 AD or even 1400 AD,
then I am not sure that the regression would hold. I think it is not
too hard to come up with numerous counter examples of cultures that
displayed some significant amount of wealt compared to
Europe. Archaeologists routinely find civilizations that disappeared
that were highly urbanized and showed a siginifcant amount of
sophistication. The Mayans fit this - they had textiles, complex
roads, textiles, written language, some currently unknown form of
political organization (probably inter-city leagues), etc.
But the Mayans disappeared so they won't show up.
I would also opine that some Mayan guy in 1000AD in a wooden house
is probably having the same standard of living as some guy in
Medieval Germany. I would not make the same claim 600 years later.
This example suggests that there is a lot of censored data - lots
of civilizations that had some wealth but disappeared. If they
existed in Africa or the Americas, then due the harsh environment
and distance we won't know about them. Heck, the popualr archaelogy
magazines are filled with examples of huge cities being discovered
in remote places.
Finally consider this: if we did do the regession in 1000AD, Europe
would be coded as a very poor place despite the fact that the Roman
Empire used to exist there. A chinese econometrician would be justified
in saying that distance from Beijing correlates strongly with wealth!!
4) Another question that Bryan implied was whether the distribution
would meaningfully change. My opinion is that it won't in our lifetimes.
One of the reasons is that our civilization (the West) has successfully
created science (which makes useful things like medicine and computers)
and markets (which distribute the goodies to lots of people). Most
societies mear the equator resist one or both of these innovations.
Societies near the equator also tend to adopt interventionist
governments, which also lowers the standard of living.
-fabio
