The concept is that we soon will have, or already have, reached peak oil production, and there is no way around declining oil production(and the associated problems) in the near future.

Just Google 'after peak oil' and go from there.

'peak oil' will explain the concept, 'after peak oil' will spell out the consequences.

If you are under 50 years of age this might be of great concern to you.
If you are over 50 it is still of some interest.
If you are over 60, "Just don't mess with Social Security."
If you're over 70, "This is gonna be fun to watch!"