It's not fashionable (to say the least) to question humanity's role in climate change, but personally I think it's important to listen to cautionary dissent.

To my non-scientist mind, there appears to be a great deal of evidence supporting the notion that human activity is having a serious effect on the planet's climate, and that it'd be prudent to take steps to mitigate that effect. But even the IPCC report is very carefully worded in terms of likelyhood, not certainty.

It seems to me that it's important for us to remember that we don't fully understand the climate, and hence we don't fully understand our role in climate change. That's not to say we should continue to dither and stare at our naval...but if we're going to take action, let's at least be honest with ourselves and proceed with our eyes wide open.