“The butterfly effect” deals with large, chaotic systems and the effects that small, seemingly insignificant actions can have on them. It’s statisically unlikely that a butterfly’s wings flapping in China could affect weather in the USA, but is still possible. Whenever sufficient additional energy ( of whatever sort ) is added to any system, chaotic or otherwise, the system at some point will become unstable and reach what is known as a “bifurcation point.” It is at this point that a small action can have greatly disproportional consequences. This is why weathermen are so often wrong.
BTW… this is also the reason why it’s so hard to predict the economies of large countries. We saw the “butterfly effect” in action during the current recession. Additional money ( read: energy ) was added to the system via sub-prime mortgage lending, setting off a chain of events that resulted in the loss of thousands of jobs, the loss of stock value, and many other serious consequences. There were other reasons, but this was the main one. Morgage lending is a very small part of the US economy, yet the effects of the so-called “housing bubble” collapsing were very severe.