I really think that the role of man in global warming is grossly overplayed. The earth has very clearly had serious climate shifts in its history without man's involvement before, why does man now have to be the cause of it?
Don't get me wrong, man has certainly done his part to muck up our environment, but the output of greenhouse gases by man, really only since the industrial revolution in the 1800s, has been very small relative to even a single volcanic eruption.
