The Malthusian Zombie

The Malthus story holds within the Sahel region of North Africa on the edge of the Sahara. There, property rights are such, more sons, more cattle, to encourage population growth and cattle growth, which then overstresses the ecosystem. Upshot: general local ecological collapse as the positive feedback of population increase and cattle increase work.

I would add that the above story is a major factor of the expansion to the south of the Sahara desert.

I think BC and some reviewers may have misunderstood - Greg Clarke's Farewell to Alms is about the *escape* from the Malthusian trap in modernizing societies: firstly in England around 1800.

Brad DeLong has a bit of a Malthusian story about Chinese stagnation post 1200 or so -- big increase in agricultural productivity with new strains of rice but a stultifying bureaucratic class prevents the population increase from generating Simon results. http://delong.typepad.com/sdj/2007/08/slouching-towar.html

Yeah, the favorable NYTimes review even has a sidebar called "Escaping from a Malthusian trap":

http://www.nytimes.com/2007/08/07/science/07indu.html?ex=1344139200&en=4c2806a790eb2152&ei=5090&partner=rssuserland&emc=rss&resub

Read David Landes' "The Wealth and Poverty of Nations" for a description of China's Malthusian trap -- the difference between Malthus' theoretical description and how it worked in practice was that it wasn't gradual like Malthus assumed, but catastrophic in timing. The population would rise steadily, then something disruptive like a rebellion would happen and the population would quickly be 20% smaller.

Not only that, but population increase makes it harder to get per capita growth in investment in production. There is a dilemma in the posting which is not known to be a valid one: that we either believe that Malthusian traps are still common in the world, or that broad population increase does not make it harder to obtain the increase in investment in production per capita, which is needed. These aspects can be isolated and their effects compared. Why is there such high correlation between low per capita income and high population growth in the world? After all, even Julian Simon himself, the arch-anti-abortionist, was quite willing to admit that he felt it was "better to have more people and a lower per capita income". Sometimes we have to choose, and that is the truth which can never die.

Niall Ferguson showed a very good perspective on the actual Multhusian studies in a piece entititled "Worry about bread not oil" in the London telegraph (and L.A. Times too, I believe).
Worth a read, as he always is.