At present the variable cost of flying my plane with a single 320 ci Lycoming engine is probably about $120 an hour.
When the Carbon Tax is implemented it might be something like $123 an hour - too small a change to notice and it won't affect my aviation.
In the last two years the rising cost of Avgas has increased my cost per hour by probably $40, a much bigger change.
Oil is a fossil fuel and they supply is finite. As the supply of oil dries up the price will continue to rise until it becomes so expensive demand drops off.
I can imagine oil at $200 a barrel within a couple of years and $500 a barrel within ten to 15 years.
If we conserve our finite oil reserves now it will soften the shock of rising oil prices in future years.
At some point I'll have to commit $30k for a new engine, but like the idea of deferring the decision for a couple of more years until there is more certainly about future oil supplies.