There's also another source of emissions that's never mentioned, and it's been going on since the earth was created. It's volcanic activity. Volcanoes pump tremendous amounts of gases into the atmosphere, and always have. The earth is much stronger than environmentalists realize. After the Mt St. Helens volcano blew up, scientists were expecting it would take at least 100 years for the area around it to recover. Much to their surprise and astonishment, it recovered in about 15 years.
The whole earth is a system, and I think it's a mistake to focus on only one thing, and start making changes without taking into account the whole system and what the side-effects might be. The earth has plenty of energy, we just need to be intelligent and sensible about how we tap into it and use it.