I having a great of frustration with the whole global warming alarm because I have yet to see what portion/estimate is man made and how much is occurring naturally. We should (and could only possibly) deal with the man made portion. The rest we simply have to live with. I am reminded that Greenland is named that because it was once green.
I should point out, before I say anything else, that I work in the renewable energy industry (and wind energy in particular) and should therefore not be considered objective as far as this issue is concerned. But then again, maybe someone might find my viewpoint interesting. I'll throw it out there anyway.
Firstly, I hate the term "global warming". It has never been a good description of the problem and scientists have been trying to retire it for decades in favour of something more accurate. Climatic instability usually does not appear to affect the world evenly: some places warm up, some cool down, some get drier, some get wetter and so on. Further, in the past it has often tended to lead to dramatic swings: in general, things might get hotter for a while, then suddenly swing into an ice age or vice versa. Relatively sudden reversals and bounces in climate are not that unusual. Personally, I don't like the term "climate change" either. Climates are continually in a state of change, this is not an unusual occurrence. A fairer term would describe the level of instability or acceleration in climatic change, but I haven't found any phrase that would be both accurate and snappy thus far...
Parts of Gore's film were ok, but I'm a scientist at heart and therefore sensationalism makes me uncomfortable. Overall, I didn't like it. I understand that you have to spin an idea and gloss it up to sell it to the masses even if it has merit to begin with, but I still felt a certain cheapening and oversimplification of the science was going on that made me grimace at points.
Part of the climate change we're seeing currently is nothing to do with us. It is "very likely" that "most" is driven by things we're doing, and in a much more complicated mix of causes and effects than just that relating to carbon. This is the concensus of a free scientific community. As one specialist rather militantly put it, "Since IPCC IV, there is no such thing as a climate skeptic, only a climate denier."
In any case, the data I've looked at myself were enough to convince me that we have something to worry about, and I have no reason not to trust their origins.
Climate change happens, naturally or otherwise. Sometimes it is dramatic. Some periods are stable, some are unstable. Most periods of erratic climate that we know of ended in an ice age. We're currently due (some think overdue) another ice age. We know with a confidence close to certainty that we can affect the climate through the things we do, even if we're arguing about the extent to which we're currently doing so. And we're not going to enjoy it when things get interesting again.
Given the above, I feel at the minute like we're kicking a sleeping bear whilst arguing amongst ourselves about how hard we have to kick to wake it up. I think we need to stop kicking as soon as possible, because it's looking like we might find out the answer.