What happens when cheap mass oil runs out, in 50 or 60 years? Trains and cars can go electric, ships can use sails and electric, but what's the answer for planes? Knowing how long it takes to get revolutionary new technology into commercial everyday service, I'd have thought there would be some good alternatives to oil surfacing from Rolls/P&W etc by now,..
But yes the big problem is over population and over consumption.
G