You are correct about the fertilizer, but it makes no difference. Coal and natural gas all have their own production peaks as well, it's not just oil we have to be concerned about.
Yes they do, but much further out than our production peak for oil.
Yes it will eventually become an issue, but not anytime soon, and so its real difficult to determine how my kid's kids will deal with this.
Again, I have to ask, are you worried about Global Warming?
Because if you are, then you are subsribing to a belief that our use of fossil fuels will go up over this century.
The belief that there is going to be a shortage of fossil fuels and there is also a need to curtail the use of fossil fuels to prevent global warming are mutually exclusive.
You can't run the agricultural industry on the same vegetable oil it has to produce for consumption, there isn't enough arable land. There simply aren't any scalable energy sources that could meet our needs in time to prevent a contraction of the economy.
It's really hard to get down to this level of usage, the record keeping just isn't that precise, but one can get an idea.
First, ~18% of our Oil becomes Diesel fuel
But, 75% of Diesel is used for highway Transportation, leaving just 4.5% of our diesel oil for other uses.
And ~75% of farm equipment is run on Diesel
But then consider that nearly all semi-trailer trucks, delivery vehicles, buses, trains, ships, boats, barges, farm, construction, and military vehicles and equipment have diesel engines, so farm use as a percent of that 4.5% of our oil use has to be pretty small.
So, yes, I do think farming can easily raise sufficinet bio-diesel to be self sustaining.
Arthur