Discussion: Fossil Fuels and the Expansion of the Human Endeavor

David Nemerson invites to the following discussion. You are more than welcome to become engaged through a comment below.

I got in a debate yesterday about the role that fossil fuels played in the explosion in the size of the human population and material economy since the early 1800s.  My thesis was the expansion from 1 to 7.4 billion humans and the much larger increase in the material economy are a direct result of the discovery and exploitation of fossil fuels, mediated mostly through chemical fertilizer and mechanized farming.

My adversary offered:
I absolutely believe we could have supported 7.4 billion on non fossil fuel based agriculture. And the population explosion was primarily due to non-fossil fuel requisite advances in disease control that occurred during the 20th Century.
I’m curious what folks here think.  And any good references that address this issue?  Obviously, sanitation and antibiotics are important proximate causes, but they are proximate in my mind.