That massive carbon footprint exists because although the Haber-Bosch process represents a huge technological advancement, it’s always been an energy-hungry one. The reaction, which runs at temperatures around 500 °C and at pressures up to about 20 MPa, sucks up about 1% of the world’s total energy production. 

Here in my state we're looking hard at mass production (global scale numbers) of 'green' ammonia.

https://fortescue.com/what-we-do/green-energy-research/green...

High-grade phosphate rock (for Phosphorus (P)) is the declining resource, or perhaps more accurately isn't matched by our ever increasing demand for it in fertilizers as our human population grows. For now at least we're coasting along on increased beneficiation of lower grade ore through washing, flotation and calcining.

It's a fair point - I'm personally in the "let's see fewer humans overall camp", I'm not advocating genocide, just in favour of birth rates continuing to decline until we're back between (say) 4 to 6 billion.

Unlimited growth in a petri dish has obvious issues, even if the dish is the surface of a relatively large sphere.