Depends what time frame you are discussing. There will be scientists and mathamaticians as long as we don't take the time to bomb outselves into the stone age.
There were scientists long before oil and there will be many long after. The natural sciences will continue to have quite a lot of interest, but the sciences that rely on vast sums of energy to carry out their experiments are in for a rough time.
For instance, the ability to genetically modify crops will bandied about for some time, but the Fermi lab with its large particle accelerator may not survivive as few as another dozen years (pessimistic outlook, that). And the geniuses in NASA, who have the bad form to be under 40, may need to purchase a few gardening books before retirement.
Hmmm... looking at posts from this morning, I conclue it quite inadvisable to watch 3 British movies in one night.

When somebody makes a statement you don't understand, don't tell him he's crazy. Ask him what he means. -- Otto Harkaman, Space Viking