A good way to scare yourself is by googling "phosphorus shortage." Agriculture requires lots of phosphorus for fertilizer, and after it's spread on crops, most of it gets washed into the ocean, where it is irrecoverable. Without phosphorus, food production will plummet, unless people come up with new ways to grow food.
In 2007, at the current rate of consumption, the supply of phosphorus was estimated to run out in 345 years. However, some scientists thought that a "peak phosphorus" will occur in 30 years and Dana Cordell from Institute for Sustainable Futures said that at "current rates, reserves will be depleted in the next 50 to 100 years."
From The Conversation:
Fertiliser use has quadrupled over the past half century and will continue rising as the population expands. The growing wealth of developing countries allows people to afford more meat which has a “phosphorus footprint” 50 times higher than most vegetables. This, together with the increasing usage of biofuels, is estimated to double the demand for phosphorus fertilisers by 2050.
Today phosphorus is also used in pharmaceuticals, personal care products, flame retardants, catalysts for chemical industries, building materials, cleaners, detergents and food preservatives.
From Critical Shots:
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The greatest natural reserves of unmined phosphorus exist in [Morocco]... According to the USGS, 42% of all phosphorus imported by the United States between 2012-2015 came from Morocco. China beats them out by a tremendous margin in production, but based on the most recent data Morocco and Western Sahara combined are sitting on 50,000,000,000 metric tons of reserves.