Fire in front of the dog.
that would have very good odds of seriously hurting it via ricochet/spall, and hurting it is worse than killing it.
i have no wish to harm any animal, much less kill it. if it looks ready to attack, fine, dead dog. but if its pondering the situation ("hmm.. is that thing good to eat?") scaring it off is fine by me. scaring and hurting it via spall so it suffers is not.
Well firing in the air has a chance of killing a human, even if a small one.
Look there is no polite solution to dangerous situations like that. Pick the one that has the least chance of harming humans, not other animals.
as i said, in that direction there is nothing but trees for several miles. literally.
nothing. at all. i could say more but it would give too much away. i fly my drone out that way sometimes. a over mile out and its the most uninteresting scenery ever.
anyway in a semi populated area its a consideration. here? ill not worry. especially as warning shots are pretty rare. the odds of one of those very infrequent rounds hitting anyone are about as zero as one can get.