Postive feedback systems destroy themselves.  Either they explode (think of hooking the emitter to the base of a transistor) or implode (stock market melt-downs.)  

Last month the price of a dozen eggs in my local grocery store went from 79¢s;/dozen to $1.69/dozen.  The answer is H5N1 - Bird Flu.  Poultry provided the main source of dietary protein in SE Asia.  The destruction of the poultry flocks there, and in China, removed them.  The other previously used source of protein was fish but the world fish stocks have plummeted.  Thus, SE Asia is turning to American egg factories for a source of protein, greater demand for a limited product drives up the price of eggs in New Mexico.

There is a secondary aspect of this, 50% of the US production of soybeans (soya) went to SE Asia as poultry feed. The previously used duo-crop rotation: corn (zea mays) and soybean, in the MidWestern US has been discontinued and a corn monoculture is being established.  Soybeans are a nitrogen fixing plant which reduced fertilizer requirements for the corn and it helped - a little - in breaking the pest and disease cycles.  

By going monocrop these farmers are increasing their reliance on oil.  As a fuel and as a source of necessarily required agricultural inputs: fertilizers, pesticides, fungacides, & so on from the petro-chemical industry.  

Running them, and their customers, into Peak Oil intimating increasing input costs for farmers.  At a time when the Supply of corn is growing.  The purchase price (Demand) for that corn is dropping.  US Midwest farmers are getting less money for growing more corn at a time when their input costs are increasing.  Sounds like bankruptcy, don't it?

This could go on, to pick one, with a discussion of how corn is used throughout the food chain which would get into cheap corn being used to feed cattle in huge numbers in limited space, the requirement of feeding antibiotics in their food, drug resistent transfer, and the reduced usefulness of antibiotics for treating human disease.  

The only thing I have run across that is more incomprehensible than the US Agricultural policy is water policy in the Southwest.  The Agricultural policy does, after hitting yourself over the head with a hammer a couple of times, does have a certain rationality.  For a loose definition of "rational."  The Southwestern water policy is just insane.  It makes no sense.  New Mexico ships water to Texas down the Pecos River and the water when it reaches the border of Texas is too salt to use for anything.  It's worthless.  Yet, every year, we ship water - of which we don't have a lot in New Mexico - to Texas.  Who can't use it and won't give it up.  The water is shipped due to an agreement signed back in the 1920s - IIRC - based on water flow measurements of, what we now know, was a 500 year flood.  

The US Agriculture policy is specifically designed to deliver the maximum amount of beef to the US consumer at the lowest possible cost.  

Southwest water policy is a crazy patchwork of Spanish Land grant law, territorial law, greed, Native American treaties, theft, bi-and-multi-state contracts, fraud, self-dealing, idiocy, the US Army Corp (Build We Must) Engineers, various federal goverment projects during the Depression, and a complete inability to cognize the Southwest is a freaking desert.  (Desert = Ain't Got No Water.)    

Things are only simple if you ignore the complexity and the inter-relationships of how the planet works.  Or doesn't.  Certainly the baser human emotions such as greed play a role - and so do the nobler emotions.  More important is the fact a lot of systems, e.g., Climate, is Chaotic.  An itsy-bitsy little tweak in a system can reverberate into a disasterous, from a human POV, shift in how that system does what it does.  


She believed in nothing; only her skepticism kept her from being an atheist. -- Jean-Paul Sartre