This video shows 15 years of data obtained via Polar-orbiting satellites that are able to detect subtle differences in ocean color, allowing scientists to see where there are higher concentrations of phytoplankton - a proxy for the concentration of chlorophyll in the ocean.
This NOAA visualization video on YouTube shows the seasonal variations in sea surface temperatures and ice cover for the 22 years prior to 2007 based on data collected by NOAA polar-orbiting satellites (POES). El NiÃo and La NiÃa are easily identified, as are the trends in decreasing polar sea ice.
Two graphs from the NASA Climate website illustrate the change in global surface temperature relative to 1951-1980 average temperatures. The NASA plot is annotated with temperature-impacting historic events, which nicely connect an otherwise challenging graphic to real-world events.