Global Warming?

There's multiple counter arguments to the correlation between Global Warming and CO2 levels, and I once watched a video with scientists stating that global warming and cooling has occurred naturally throughout the Earth's lifespan; rather than high CO2 levels causing a rise in temperature, they suggested that previous data indicated the Earth's natural rise in temperature in turn caused higher CO2 levels.

I'm not saying I believe this, but I thought it was interesting. If I can find a link to the video I'll post it.