I've been reading Charles Mann's latest book Wizards and Prophets, which was released earlier this year. Overall, I've enjoyed the book. The subtitle, "Two Remarkable Scientists and Their Dueling Visions to Shape Tomorrow's World" is an apt description for much of the content, which describes food, agricultural, and environmental problems through the lens of Norman Borlaug and William Vogt. The history is informative, and Mann gives a fair comparison of the underlying philosophical differences, which he attributes to Borlaug and Vogt, driving much of the debate today around food, agriculture, and the environment.
I am very much in the "Borlaug-wizard camp" (which advocates for innovation, science, research to solve food security and environmental problems) but I came away with a better appreciation for the Vogt-ian, prophet point of view (focused on resource constraints, ecological limits, need to reduce consumption, etc).
While I thought the book was well done and well worth reading, Mann gets one aspect of this debate wrong. Because I've seen other writers make the same mistaken point, it's worth delving into a bit.
Throughout the book, Mann refers to the Borlaug way of thinking as "top down" and the "hard way," and he contrasts this with Vogt's approach which he depicts as "bottom up", "localized", etc. This is exactly backward.
Mann aptly describes a core belief among the prophets: that there are finite resources on earth and just like any other species, we will grow exponentially until we exhaust our resources, and then our population and civilization will collapse. The analogy is a jar filled with few fruit flies given a fixed amount of food. Initially, the flies have ample resources and they multiple rapidly. However, at some point the population becomes too large for the fixed food supply, and the population collapses. The fruit fly population follows something like an S-shaped curve over time.
Moving from flies to people, the issue is typically described in a Malthusian manner. As the graph below shows, as we add more labor to a fixed amount of land, diminishing marginal returns kick in and the amount of food available per worker eventually falls.