I like to think that I'm pretty good at sorting out the BS from the actual facts, but with global warming, I'm having a hard time determining what is actual science, and what is politicized pseudo-science. Just for reference, I have generally accepted that human actions have been responsible for the current changes in the Earth's climate. However, I recently heard a statistic that put a small seed of doubt in my mind. The statistic stated that out of the total greenhouse gas output per year, humans are only responsible for 3% of that amount. The rest is due to natural processes. Question 1. Is this true? Like I said, it's hard to know what information out there is reliable Question 2. If this is true, how much of an effect does that 3% have? By extension, our efforts to reduce our carbon output can only affect that 3%, so what effect can that have on correcting the problem? I realize that the ecosystem and climate are ridiculously complex, and that a 3% change could very well have a profound impact, but I don't personally have any concept of how sensitive the climate would be to such a change. That's basically what I'm asking. Question 3. This is a bit more hypothetical. We are currently making efforts to reduce emissions and burn cleaner fuels, but the likelihood is that we humans will eventually burn all of the fossil fuel we can get our hands on. The emission problem will probably only go away when we run out of fuel. With this in mind, has anyone ever tried to calculate the total amount of fossil fuel available on earth, and what the effect would be if we simply burned all of it? Wouldn't that give us the answer we're really looking for? If we could answer that question, we'd have a pretty good idea if we're going to kill ourselves off or not. So yeah, how much fossil fuel is there, and if we simply burn all of it, do we survive? Again, I have no idea what information to believe at this point, so any answer based on (gasp) actual scientific fact would be a breath of fresh air.