A hard core reality that nobody wants to agree with or even hear about is that our society has evolved into a totally overpopulated, out of balance mess. And maybe nature is just taking over by doing what nature does..... trying to repair itself. We resist because of empathy and love for others but in the end nature will have its way and obtain a healthy balance. Floods, tornadoes, earthquakes, forest fires....none of those things are pleasant when they are happening, but the end result is always good.
I don't think it is possible to eliminate or even substantially decrease killings any more than you can eliminate or decrease other "disasters". It is just an unpleasant and hurtful thing that periodically happens.....some years more than others. And that's all there is to it, period, end of story.