Whenever we do things that have merit, like accomplishing good deeds, sharing, overcoming negative reaction, etc., not only is it good for us and our soul, we are actually adding to the positive side of Universal Balance .
Let's take this further. We hear some news that doesn't make us happy. Well, if we react "naturally" by being angry, or sad, or upset, even though it is totally understandable, we actually make the scale tilt to the negative side. Right! We only add to the negativity in the Universe by reacting this way, since we add to the negative side of the scale.
Ha! So you'll ask me, how am I supposed to react when I hear a story about a child being accidentally shot on the news? Why not be angry, and outraged? Well, for one, identify what you are feeling. But then, let it go by replacing it with a feeling that is more like compassion, and go off to do something positive for someone else: Make a phone call to a loved one you haven't spoken to in a while, cook a meal for someone who just had a baby, hug your kids and tell them how much you love them, let the lady at the grocery go in front of you, etc.
That is exactly how you can help and prevent in a way you can't possibly imagine more negative events to occur. You can be that change.