Look at what has happened to the scarcity of salt over the past 100 years.
The top chart adjusts nominal salt prices to account for the general rise in prices since 1900 using a measure of the CPI’s broad inflation index. The bottom chart takes a different approach to adjust the salt data. It looks at the hourly wage of a typical manufacturing worker and asks how many hours would a typical worker need to work in order to secure a unit of salt.
(note, I imputed the hourly wages for 1915-1918). Salt data from USGS, CPI data from BLS and wage data from Historical Statistics of the United States and BLS.
By any metric, the scarcity of salt is no higher today (in fact, it is much lower) than it was over 100 years ago, even as human consumption of salt has rocketed with economic growth and population growth. In real terms, salt prices have fallen by over 48% since 1900 from $67.31 per metric ton to $34.54 per metric ton today. In 1900, it took a typical manufacturing worker 12.2 work hours to secure himself a ton of salt. Today, a similar worker would only have to work 1.8 hours to get it – a decrease of over 85 percent over the course of the century. And as I will show you, these are lower bounds for just how scarce salt really has become. Salt prices would have to rise to $244 per metric ton to make it just as hard for a typical worker to get it today as it was in 1900. Alternately, if salt prices remain unchanged, the typical worker would have his pay slashed to just over $2.82 per hour in order to be in a position that his 1900 counterpart was in.
I just saw a documentary on the History Channel about the formation of the Great Lakes. The entire area beneath Lake Michigan and most of Lake Huron and part of Lake Erie is an enormous salt deposit – including trillions of metric tons of salt. Each year less than 300 million metric tons of salt are produced and consumed around the entire world. Even if we tripled our salt consumption, the deposits beneath Lake Michigan alone would very conservatively last 1,000 more years. Furthermore, the actual oceans contain a virtually inexhaustible supply of salt and I am ignoring every other salt deposit around the world. There are far larger deposits in China, for example, than there are in the United States.
But this is just salt, right?