the issue is not whether or not the earth is warming. Without the aid and benefit of internal combustion engines, coal fired power plants, etc. Mars is warming as well. This issue is whether or not mankind's contribution to global warming is significant. Keep in mind, global warming and cooling have taken place long before man spewed his first hydrocarbon into the air. If one actually studies the science of global warming, rather than the emotion of global warming one can't help but conclude man does contribute to global warming, but on an insignificant level. Completely eliminating man from the face of the earth would not eliminate future climate change.