The Crash Course - Chris Martenson [104]
Therefore, any study of the extent that plant yields are dependent on nitrogen applications is really the study of the effect of fossil fuels on farming yields. As long as there are ever-increasing amounts of natural gas to dedicate to making nitrogen fertilizers, then the system we currently use should continue to function. But if this isn’t the case—if it turns out that natural gas becomes limited in some way (which indeed it someday will)—then we need to seriously think about how we’ll manage that situation.
If we lacked the energy to make nitrogen fertilizers, then plant yields would suffer enormously, until and unless we could figure out a practical way to return the harvested nitrogen back to the land in a usable form. Currently, the number one eventual destination for applied farming nitrogen is the ocean, which is where we send most of our sewage. Right now we can “afford” to do that because we have the energy to waste, but in the future it will be a sure bet that we’ll have to find ways to close the loop and return these essential nutrients to the land and the soils upon which we depend.
The story of phosphorus is even more urgent, if not alarming, as our only source for this utterly essential element is from mined rocks. Again, we “mine” phosphorus from our farming soils and send it out to the sea to become hopelessly diluted, never to be recovered. Once thought to be virtually inexhaustible, rock phosphate has been mined in ever-larger quantities over the years to support our exponential need for more food, and we can now see that a peak in this important mineral resource is plainly in view.
Our supply of mined phosphorus is running out. Many mines used to meet this growing demand are degrading, as they are increasingly forced to access deeper layers and extract a lower quality of phosphate-bearing rock (phosphate is the chemical form in which nearly all phosphorus is found). Some initial analyses from scientists with the Global Phosphorus Research Initiative estimate that there will not be sufficient phosphorus supplies from mining to meet agricultural demand within 30 to 40 years. Although more research is clearly needed, this is not a comforting time scale.6
This is the exact same story that we’ve seen already for petroleum and other minerals. There is a fixed quantity of this vital mineral. It’s being mined in ever-larger amounts, and it’s depleting rapidly. That it will someday run out isn’t in doubt; such a fate lies in the future of any finite material that’s consumed. But “running out” isn’t really our most immediate concern; “peaking” is. If farming yields must grow to meet future demand, and those yields depend on phosphorus, then the peaking of phosphorus is going to put enormous pressures on efforts to increase yields.
Modern farming practices represent the effective mining of nutrients—a one-way trip from the soil to the sea—which we combat by mining or creating replacement nutrients elsewhere and then spreading them back on the land, using a lot of energy in the process. Right now our approach to nutrients is like a giant arrow that begins where the fertilizers are mined, passes through a farm, goes to a plate, and then out to sea.
Soil Erosion and Desertification
Even if all the soil (and its critical minerals) were staying in place, instead of being dispersed out to the ocean, there is another way in which modern farming practices aren’t sustainable.