Kardashev Scale
> The limitation of biological life-form and the evolution of computing technology may lead to the transformation of the civilization through Mind uploading during the transition from Type I to Type II, leading to digitalized civilization).
Neal Stephenson's recent novel "Fall; Or Dodge in Hell" deals with humanity taking its first steps down this path in the near future.
I think fossil fuels moved us too far up on the energy usage scale before we were ready for it.
A more accurate measure would be the average amount of wellbeing a civilization extracts from its consumed units of energy.