OPEC and Big Oil face a looming disaster because of shale energy, writes Steve LeVine at the online news site Quartz.

Citigroup's top energy economist issued a report, "The End is Nigh," saying that permanent changes are under way and hollowing out oil demand, LeVine's story says.

LeVine: "The biggest instrument of change is plentiful and (in the US) cheap natural gas, to which whole swathes of the global economy could turn."

Read the whole article here.