One must not think globally, you have to influence the people you know and make a difference on your local community. There are some things that are out of your control, it's an unfortunate fact that you have to accept in life, similar to the fact that everyone dies. The sooner you know that there are some things out of your control, the better and you can do whatever you can to influence that change, to make sure that things get better in the world. Once you have done all that you can or all that is reasonable to do, then there is no need to worry about it, because worrying about problems around the world doesn't help you, it doesn't help the people around you and it doesn't help the people in those problems. Do what you can and once you have done that know that you have made a difference.
Also, I just want to quickly pose this nice little theory on you; it's the idea that true altruism doesn't exist, every one does everything for selfish reasons. If you gave all your money away to someone else, you'd be doing that because it made you feel better, because the guilt of knowing you have money when someone else doesn't makes you sad.