NASA's award-winning Global Climate Change: NASA's Eyes on the Earth website offers nifty gadgets for visualizing global climate change. Check out the feature Vital Signs of the Planet for the latest on CO2 (now 389 ppm, highest in over 650,000 years), temperature records (2000-2009 was hottest decade on record), Arctic sea ice minimums (plunging 11% per decade with 2009 resulting in the third least ice cover on record), rising sea level (up 57mm since 1993), and the size of the ozone hole (about 9.3 million sq. miles).
You can see the orbits of NASA satellites, enter the Climate Time Machine, and surf rising sea levels.
This is a visually spectacular website loaded with authentic original content created by NASA scientists and interpreted by NASA's communications team. Good stuff from money well spent supporting NASA.