Some friends and I have been talking about peak oil and the implications of actually finding a cheap, plentiful alternative energy source.
I'm not a global warming expert (although I have stayed at a Holiday Inn Express), but the role greenhouse gasses play is that they increase the retention of the ambient heat that we generate. Instead of letting it be emitted as infrared into space, they reflect it back or store it as heating and emit it back. The CO2 itself doesn't generate any heat itself, it just traps the heat we create (hence the name "greenhouse" gas). So global warming is an issue of ambient heat generation AND our inability to dissipate it because of greenhouse gasses.
The role that energy production and its use plays in heat generation is covered in the second law of thermodynamics which deals with entropy. All energy is, over time, broken down into unusable heat, because the entropy (disorder) of all physical systems increase over time. Meaning: every single bit of energy we generate and use eventually turns into heat. It may be a multi-step process, but as you drive your car down the road, your engine (electric or gasoline) generates heat; your tires generate heat from friction with the road; your car generates heat from friction with the air; the refinery that made the gasoline generated heat in its production. It all becomes heat. You can't get around this: it's the way the Flying Spaghetti Monster built the universe in his/her/its/their infinite wisdom. "Heat death" is pretty much the ultimate end of everything. When we're dead and buried, as we rot we generate heat, as our bodies release their stored chemical energy.
If we have some form of really cheap, really easily had energy, such that our energy production and use really increases, our heat generation rises by exactly that same amount. Greenhouse gasses in the atmosphere means that heat gets trapped instead of being radiated away as IR. But even if we didn't have any greenhouse gasses in the atmosphere, there is a physical limit to how much heat can be generated away per unit time. Basically, cheap available energy means we eventually cook ourselves to death. Literally.
Are there ways around this? It's been seriously suggested we build giant lasers that would somehow (this part is really unclear to me) radiate waste heat into space. I can imagine an SF story where we fry some passing alien craft and start an interplanetary war.
This has been proposed even for space craft with large power plants, since the only way to get rid of heat in space is by radiation; neither convection nor conduction works because there's no material to which to convect or conduct, like air or water. This is one of the reasons the Space Shuttle has big honking radiators built into the cargo bay doors and why they have to open them up when in orbit, even if they're not using the cargo bay. Their waste heat has no where else to go. This also places a physical limit to how much energy the Shuttle can expend, and how big a Shuttle we can build.
Quoting Robert Heinlein: TANSTAAFL. Cheap energy means increased heat production. In a way it just moves the problem somewhere else.
If you think about it, what is oil or coal? It's stored chemical energy. Where did the energy come from? From plants, and maybe some dinosaurs, that lived, ate, and grew millions of years ago. Because no system is 100% efficient, those plants (and dinosaurs) consumed a LOT more stored chemical energy, in the form of plants, dinosaurs, and soil and chemicals that once was plants and dinosaurs and rocks, than they created. Today we're taking advantage of a process that began millions of years ago, and that we cannot replicate. We can't make more oil because, besides the fact that we're impatient and can't wait millions of years (hence we invade small middle eastern dictatorships), the natural resources that went into making the oil, the incredibly rich biosphere, doesn't exist anymore. It went into making the oil that we DO have right now. Pretty much a one-way process.
Just like entropy and heat death.