http://earthobservatory.nasa.gov/Library/CarbonCycle/ - A description of the carbon cycle.
http://www.educapoles.org/index.php?/fun_zone/multimedia_animations/why_it_cold_the_poles/&s=7&rs=13&uid=119& lg=en&pg=5 - A simple animation from the Polar Foundation (http://www.polarfoundation.org/) explaining why it is cold at the poles.
http://www.educapoles.org/index.php?/fun_zone/multimedia_animations/the_greenhouse_effect/&s=7&rs=13&uid=121& lg=en&pg=5 - A simple animation from the Polar Foundation (http://www.polarfoundation.org/) explaining the greenhouse effect.