How can an individual, possessing limited information and abilities, make a difference globally?
Strange as it may seem, one place to begin in answering this question is by looking to the behavior of ants. Science Dailyreports on a study of utility maximization--basically making the most advantageous possible choice--among ants.
This study finds that: "...researchers at Arizona State University and Princeton University show that ants can accomplish a task more rationally than our--multimodal, egg-headed, tool-using, bipedal, opposing-thumbed selves." The study's authors continue: "This paradoxical outcome is based on apparent constraint: most individual ants know of only a single option, and the colony's collective choice self-organizes from interactions among many poorly-informed ants."
In an ant colony all individuals are members of an organized, integrated, highly interactive society. As such they continuously engage in collective decision making. A single ant is nearly mindless, and possesses little knowledge or information. However, rational decision-making emerges out of the constant interactions between many ants, sometimes at or above the human level.
I have already written extensively on the scientific miracle of emergence, so I will not go into detail here, other than to note that emergent properties are collective properties, they emerge out of the interactions of their constituent elements or members. Emergent properties cannot be reduced to the sum of their constituent parts. The whole is greater than the sum of its parts. We see this principle of emergence vividly illustrated by the powerful, rational, utility maximizing emergent group-mind of an ant colony.