In a novel I'm working on I am bringing magic back. Magic as in Mana -- energy from the ground or from the Earth. I want the experience to be as near to it happening today, as far as story lines and effects and focus. We're busy people today. It would be a major event but not all at once and not for everyone at once.
There are two effects that I want to happen as soon as possible in the story and one is that the sky is going to turn green. The other is that oil is going to begin losing its covalence -- it's bonding-- the individual molecules are going to lose their attraction to each other, reducing what is left to a dusty sludge.