You two debated this as a philosophical or even moral issue, but it changes everything when you look at it from the natural hazard prospective. It doesn't even have to be a subjective matter. Picture this - you know the climate change is happening and you understand that some colony of animals will surely vanish because of that if you wont do a thing about it. Doing something could mean just taking a few pair of animals and relocate them to a safer area. Do you think that the survival of such descending colony of animals mean anything (to anyone)? Who can argue that it won't be our time (and obligation) to reduce the risk of having the only known capable civilization residing on only one planet or galaxy?