pstarr wrote:John_A, I don't believe you understand Duncan's theory. As I understand it his Gorge is not dependent on natural-gas fired electricity but rather energy availability/capita world-wide. He uses electricity as a measure of industrial production.
Duncan has several versions of his theory, don't know if he was updating as he went or just hoping to get it right by modifying it along the way. But I think you are quite right that the overall idea is that it is a per capita energy angle, except that per capita energy hasn't changed much since the 70's, I believe TOD did an update at some point in time and discovered that it had actually gone up as of late.
His update at the Energy Bulletin was where I found the cliff date for 2008. I think this is the place I found the north american natural gas reference.
http://www.mnforsustain.org/natural_gas ... n_1203.htm