According to UN sponsored research, I tonne of N nutrient, made in a modern, efficient USA fertiliser factory, typically takes 21,000 (yes, twenty one thousand) kWh to manufacture and deliver to farm. Yet, we lose around half to groundwater with rain or irrigation. This will dramatically affect how we farm. Part of the answer is to recycle waste to farm land. How to do this safely and how doing this can also reduce irrigation need by up to 90 % is detailed in a referenced work on sustainable agriculture. All these and how the global population will reach crisis, and when, can be downloaded for free on the Sunday 12 Feb. Search Survival” by Bill Butterworth Amazon.