As you all know, I'm an astronomer by training and one of my areas of concentration was planetary science. When it comes to arguments on global climate change I'm universally dismissive of easy explanations on both sides, i.e. I look at the data and understand this is a high Hausdroff dimension attractor in a non-linear system.
Climate change is, based on the evidence, real. It seems humans are likely responsible for part of it but certainly not all. This is not being caused by sunspots or variability in the Sun (unless the Sun has somehow become a Cepheid variable). It's not clear than we can do anything about it at this point and if we could, what exactly we should do. The planet has been inhospitable to human civilization before and is likely to be again.
All that said, I have met Al Gore's new movie with more than a dallop of skepticism. It a complex issue that doesn't make for good politics.
Here is a professional take down, piece by piece of the movie. Seems like he did a pretty reasonable job.