Redundancy vs. Interdependency

John Robb has shared some of his early ideas as he brainstorms for his forthcoming book on "Resilient Communities". This recent post describes the need for local capacity in "personal fabrication", opining that "in the longer term, [disruptions don't] need to occur." Communities possessing the ability to create (at low cost and small scale) locally desired goods could, in John's words, "... advance economically and in quality of life faster than communities dependent on traditional centralized sources of production."

The following day, Tom Barnett linked a Bloomberg article under the heading "Early signs of the growing food hyper-interdependency" and Shlõk posted a short piece on "Piggybacking on Existing Infrastructure" (calling it a bad idea).

These two articles underscore the competing notions of of "economic specialization" (which is the at the core of interdependency) and "local redundancy". In an ideal world, with infinite resources, local capacity can be built to suit local needs. However, when resources are finite, the concept of "opportunity cost" becomes paramount: What can I not do if I do this?

For disaster planning, we tend to overestimate the availability (and capacity) of local infrastructure: first responders on the scene, relatively intact communications infrastructures, availability of critical resources like water, ice, medicine. After Hurricane KATRINA in August 2005, however, we saw the impact of lost infrastructure: first responders who had evacuated themselves, cell phone towers with their power generators flooded, impassable transportation grids unable to deliver needed supplies.

I have argued in this 'blog for greater self-reliance -- but how far can we go? What are the practical limits of building and maintaining a local infrastructure that can satisfy all local needs? And would such "islands of self-sufficiency" lead to greater sectarianism?