I draw your attention to a post by aeldric in The Oil Drum: Australia/New Zealand entitled
The Networking of Resource Production: Do the Networks Give us Warnings when They are About to Fail?
This is an excellent post discussing how different resources are networked. For instance, it requires oil to mine coal or aluminum. The inter-relationships between the different resources make it extremely difficult to recognize when shortages are about to become critical. And when they do become critical, they can seriously alter the functioning of the world's economy.
The post provides a simple explanation for the networking that exists and how this can lead to problems in the future. I found the comments to also be engaging and helpful.
I recommend you read this article and consider what it is saying about our future, and when that future may happen.
Sam Penny, the Prudent RVer