Metro Boy,
The greenhouse effect is a natural phenomenon that is being accelerated by our fossil fuel burning.
Man's input comes from various greenhouse gases - methane, NOx, N20, and most importantly CO2 or Carbon Dioxide (created in the combustion process - the same chemical reaction as respiration).
The atmosphere already has carbon dioxide in it (0.03% by volume) and it is not a poison, or harmful in any other way. But adding so much to it, as we are, is likely to have an impact on insolation (because the CO2 lets shortwave solar radiation in, but reflects outgoing longwave radiation back to the earth). As we all know, insolation plays a major part in our weather systems and temperature!!
The fear is that with humans adding so much CO2 so quickly, the climate will change faster than the ecology can keep up - so species die, food chains collapse, and - here's the important bit - no-one knows the exact consequences, but they are not likely to be good!!
The climate has changed in the past, but it has been at a much slower rate - and while not all species survived, it happened slowly enough for the whole ecology (food chains etc.) to adapt, and keep running.
So to get back on topic, there is plenty of oil around, and new drilling techniques will increase the available reserves - there will be more demand with the economic expansion of Asia, but this won't be a problem in the next few years.
However, as we start to realise the ecological impacts of what we're doing, this may well have a HUGE impact on aviation - as well as shipping and cars and trucks and power stations and farming (cows fart, you know)... aviation won't be singled out, but will be a part of the rationalisation.
Someone much smarter than me once said (along the lines of) "The ecology can get along fine by itself without our economy... but we can't have our economy without that ecology!"
(ducks to avoid the incoming flack...)