"But you would go back to those yields as well. It is with the aid of chemical fertilizers that brought about the green revolution."

Erm, I know a couple here who grow crops organically, and they would be the first to pull you up on this point. It took me all of 5 seconds to Google this:

http://www.news.cornell.edu/stories/July05/organic.farm.vs.other.ssl.html
http://www.cnr.berkeley.edu/~christos/articles/cv_organic_farming.html

Crop yields from modern organic farming are often equal to or in excess of conventional farming.

"You can never solve a problem on the level on which it was created."
Albert Einstein

thats not definitive proof..
but oh well. believe what you want, the green revolution was simply industrializing agriculture. without the energy basis behind that industrialization we will go back to the pre green revolution level of food production if not less due to soil damage between then and now.

I agree that the vast availability of energy was probably the most important part in the green revolution, but that has nothing to do with my comment. Chemical (in the loose sense of argi chem fertilisers - as opposed to manure type) fertilisers are not necessary to maintain high yields.

"You can never solve a problem on the level on which it was created."
Albert Einstein