Lines of evidence: How do we know about climate change?

For anyone still confused as to how we know that the climate is changing and that the changes are largely driven by human activities, this 26 minute video from the US National Academies gives an excellent and authoritative overview of the evidence. None of this is remotely controversial amongst the world's peak scientific bodies, despite much obfuscation and confusion through the media and blogs for political, economic and ideological purposes.