Unless I'm missing the point completely, that's way before Frank-Caro and Haber-Bosh processes were used industrially for fertiliser production, though. Even with those tech constraints, you could probably double those numbers as long we can reliably fixate nitrogen.
Franc-Caro: Haber-Bosch: Michael Pollan pointed out that the principal ingredient in all foodstuffs is corn, and that the principal ingredient in corn is oil. 800 trillion BTUs in fossil fuels for American agriculture in 2012 - granted, US total energy use in 2017 was 97 quadrillion BTUs but "fixating nitrogen" is an energy intensive process no matter how you slice it. I think you need to drive down the Grapevine into LA amongst all the food trucks and look West and see the giant pipes pumping water uphill to Los Angeles to really get how much energy it costs to be alive these days.a reactor vessel at about 1,000°C.
using a metal catalyst under high temperatures and pressures:
Americans have held relatively steady since about 1970 but what that graph shows is the spike as the rest of the world approaches America's energy use since 1970. "Given a long enough timeframe" is about half of science fiction. What I know is it was "the Great American Desert" before we tried to get people to move there, then it became "the Great Plains" and I'll betcha a dollar it'll be "the Great American Desert" again.
Thanks, I have to confess that I'm not that good with US history/geography and it always surprises me there were (and are) massive droughts. Also, sorry that my previous comments sounded douchier than usual. Had a bad couple of days, hope you can understand.
Ohhhh, my friend you are missing out on some awesome history. The thing that kept Americans from expanding sea to shining sea? The Comanche. Archetypal reavers, barbarians, primitives with a thin culture compared to the other tribes they raided but as soon as they gained horses they became ruthless, efficient mass murderers of all comers. At one point several tribes banded together with the Spanish to drive out the Comanche... and failed. Comanche ate buffalo. The United States took on the massive project of driving the buffalo to extinction, basically intentionally destroying the ecosystem of the bulk of its landmass to drive an enemy to famine. And then once the Comanche capitulated they invited the flotsam and jetsam of the country to go tear up the buffalo grass and plant wheat. And then it didn't rain and the wheat died and the blowing dust from the ecological apocalypse traveled 2000 miles to rain down on the capitol. 'murica. Go big or go home. I didn't find your previous comments douchey at all. I didn't really consider the gestalt Malthusian problem until reading about six or seven different kinds of shortage-based apocalypse.