[aerohead]

Originally Posted by sendler

And it's not just energy depletion that will force a downward trend on economies. Most resources have been diminished. And have been harvested according to the best, first. So what remains of ore grades and overburden are more energetically remote to get.
.
In Jiangxi province, for instance, the city of Jingdezhen, famed for its high-quality clay, has been a center of porcelain production for centuries, serving both China’s imperial courts and, more recently, American and European markets. But after hundreds of years of exploitation, only about one million tons of clay remain—two percent of the area’s historic reserves.
.
https://www.nationalgeographic.com/c...id=41266339255
.

There's a list of strategic resources recognized by the world community that we'll have to keep in mind.I don't have that in hand.
Other than those,there may be some wiggle room with respect to substitutions.