Science proves beyond all reasonable doubt there is no God, what does that do to evil?

If science were able to prove beyond all doubt God does not exist, how does that change evil or how would evil even exist? Could one say ISIS was evil because they do something that was oppose to the person or group making the claim? How valid is their accusation when someone can say what they are doing is evil? Is evil a popularity game where those with greater numbers get to say what or who is evil? How great a number do you need and how do you know if you have achieved it? Will there be a global council on evil, and if there was just because they say something evil it is just their demarcation based off their peculiarities, so how is that truly valid for what is evil?