Art and the Internet can be a powerful way to inform and alarm about environmental issues. Check out this powerful climate change animation from Hippoworks, who are doing great work in this area. It's called "On Top of This Planet." As my 11 year old daughter said, it's "very good and very sad."
We also love their "Extinction Sucks" animation.
Hippoworks makes it easy to post their animations from your website or blog. See them at: http://www.hippoworks.com/