Fairness is an efficiency parameter if we look at the whole global civilization. It is not an efficient way of meeting human needs if one billion people starve while another billion have excess. It would be more efficient to distribute resources so that at least vital needs were met everywhere. Otherwise, for example, if kids are starving somewhere, dad goes out to slash and burn the rain forest to feed them - and so would I if my kids were dying. And this kind of destruction is everyone's problem, because we live in the same ecosphere.