local manufacturing/pollution/survival of humans

We are getting closer to the release of the second editions of "China's Weaponized Economy" and "World War C" (previously Trust-How we lost the war with China.
As we approach this, a little diversion to the associated issue of increasing local manufacturing is in order.
Increased specialization can mean that critical industries are isolated.  In some cases critical products are made in a single location.  More than defeat to the warlike tendencies of the Chinese economy are at stake in this discussion.
Primitive man had to survive many disasters, in these cases they were all naturally occuring events.  A recent minature ice age may have brought on the French Revolution and this is a minor matter.
Previous disasters include the actual ice age which may have accelerated natural selection by a large factor and given rise to a sufficiently intelligent species to bring us to where we are today.  In a modern ice age, the lack of dispersed manufacturing would undoubtedly mean a breakdown in civilization, especially as that would be exacerbated by the scramble for the available land and resources without a shortfall of weapons and people.
This also goes to the short term versus long term intelligence issues of reigning in the random population growth we experience.  Those who take the approach that no one should feed pets better than the worst fed human, ignores the fact that population should be tied to both local food production and local manufacturing.  It should not be tied to the ability to provide food regardless of the global consequences.  That only makes sense if we want a world where people stand shoulder to shoulder broken only by sufficient land to make sure everyone gets enough to eat.  That type of world would not be worth saving.  Unfortunately, that is the only world we strive to as a race.  This is one of the many areas where China is far in front of other countries in planning for the future.
Local production and local food production, at least on some level, allows for people to focus more on these issues.  It doesn't mean that critical industries cannot or should be be localized.  You cannot have people build airplanes in every country or in every state, but some level of production and certainly food production tied to the population should be localized to the extent possible to ensure that critical skills are dispersed.