The U.S. will run out of easily mineable domestic deposits of phosphorus within the next 18 to 30 years.

[Mic Drop]

Why is this catastrophic? Let me count the ways…

• Phosphorus is an element. It cannot be synthesized outside the heart of a star. When it is gone, it is gone. You can't just go whip it up in a lab when you run out. The way we apply phosphorus to our crops ensures that only 10–20% actually gets into the plants we fertilize with it. The remainder gets locked up chemically in the environment or gets washed into the watershed and down into the depths of the ocean, where we can't reach it. The waste of this limited resource is like buying 10 gallons of gas, putting 2 into your tank, and pouring the rest down the drain.
• The current US methods of ‘conventional’ agriculture are highly dependent on heavy applications of phosphorus to maintain yields. Since phosphorus is highly reactive, it quickly binds with things in the environment and becomes unavailable to plants. Phosphorus is usually the single most limiting factor in plant nutrition. For example, it has been found that the yield potential of corn (maize) is determined by how much Phosphorus is in the plant's tissues by the five-leaf stage. This means that the maximum amount of grain a corn plant can produce is determined by the time the plant has developed five leaves.
• We have already reached peak Phosphorus globally. Price increases are on a track similar to that of oil. The major difference between these two limited resources is that if you can't afford to buy gas, you don't drive. If you can't afford phosphorus, you don't eat. Once people can't afford to eat, civil unrest ensues.
• A whopping 75% of the world's known phosphate reserves are controlled by one man: the King of Morroco. Morocco is in a considerably unstable part of the world. The bulk of the rest of the reserves are in China and Russia, neither of which are very friendly to the US. Once we run out of our own phosphorus and are forced to pay the same prices that other countries do, you can bet that cost will be passed down to the consumer. Once again, when people can't afford to eat, civil unrest ensues.
• Putting too much phosphate fertilizer down on the majority of our croplands over the past 75 years has killed off the microbes that evolved to recycle phosphorus to plants and keep the soil alive. It can take 15 to 20 years to restore those microbes and to restore soil to its proper biologically active state. If we run out of phosphorus in 18 years and haven't even started the process of restoring our soil and changing how we grow our food, we will reach a food crisis that could very well be the end of our civilization as we know it. EDIT: I realize this is a bold statement, so I want to explain it a bit more. The US exports a HUGE amount of grain (wheat, soybeans, corn, etc.) to other countries. When we begin to have trouble feeding ourselves, there will be a cascade effect, since this means we will no longer have a surplus to sell. Other countries who buy from us will be unable to feed their people, too. As Marie Antoinette found out the hard way, hungry people are desperate and angry people. Wars, revolutions, mass migrations and subsequent government collapse are likely scenarios here. The likelihood of this catastrophe occurring is also very great, because while the majority of the US land mass is given over to agriculture, the majority of Americans are utterly ignorant about how their food is grown. For an in-depth look at how this type of collapse occurs, read the book Dirt: The Erosion of Civilizations by David R. Montgomery. (Available at Amazon)
• Biofuels, especially ethanol made from corn feedstock, are an absolute boondoggle of the highest order. We are using two very limited resources (oil and phosphorus) to grow an extremely inefficient replacement for one of those limited resources. How does that make any sense?
• The US government and the Agrochemical industry are partners in subsidizing the unsustainable and environmentally damaging methods used by most farmers in the US. They are literally paying for this catastrophe in the making, when they should be rewarding farmers who are practicing regenerative agriculture.