There's a lot of free information available on the internet, but sometimes there's information that's not free, but is worth the price. For anyone who wants to understand the science behind climate change: What governs Earth's climate, how and why it changes over time, what humans are doing that affects it and why we know what we know; as well as what we don't know and what needs further research. Why carbon matters and why the relatively small amount we are adding to the environment makes a big difference. For anyone who wants to understand this, I highly recommend the Teaching Company's six-hour lecture series Earth's Changing Climate taught by Professor Richard Wolfson. $40 on DVD, $20 by audio download (plays on any MP3 player, or you can select MPEG4 format for iPod). I think those sale prices end today, but if you call them within a day or two and tell them you just learned of it they might give you the sale price.
