According to Wikipedia: Chaos theory is a branch of mathematics focused on the behavior of dynamical systems that are highly sensitive to initial conditions. 'Chaos' is an interdisciplinary theory stating that within the apparent randomness of chaotic complex systems, there are underlying patterns, constant feedback loops, repetition, self-similarity, fractals, self-organization, and reliance on programming at the initial point known as sensitive dependence on initial conditions. The butterfly effect describes how a small change in one state of a deterministic nonlinear system can result in large differences in a later state, e.g. a butterfly flapping its wings in Brazil can cause a tornado in Texas.
So, when we wonder how our seeming small actions can impact the greater good- remember that we are all connected. Each to everyone and everything else forming a web of matter and information- distinct and yet intertwined so that it is affected by the smallest of change.
Knowing this it is very important to carefully choose our thoughts and actions. There is so much pain and misery in our world- with rising anger and violence. Ordinary citizens like you and I may not be warriors on the frontline, but we can help to bring peace and equanimity by exhibiting it in our everyday actions. Being loving or at the very least kind to everyone we interact with, showing grace even when we may feel that the other person is totally out of line- such small actions can play a pivotal role in bringing balance to our increasingly un-balanced social and global environment.