" What we are doing to strangers in other communities right now is, therefore, far more serious and far more widespread than the harm we would do if we were in the habit of occasionally sending out a group of warriors to rape and pillage a village or two. Yet causing imperceptible harm at a distance by the release of waste gases is a completely new form of harm, and so we lack any kind of instinctive inhibitions or emotional response against causing it. We have trouble seeing it as harm at all. "

― Peter Singer , Practical Ethics