Phosphorous is mined with diesel powered earth movers. And transported around the world on diesel trains and ships. So in essence, fertilizer is made from liquid fossil fuel. And we are using it faster than we are finding more (phosphorous and oil). The USA has 25 years left and so will be relying on importing most of what the world needs for us to keep feeding it. In 200 years we will be desperately trying to scrape it back up from the ocean floor where it has washed away. With no fossil fuel left for our machines and ships to work with.
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Phosphorus: Essential to Life