Turning Up the Heat on Global Warming
Ever heard of the "Heat Island Effect?" That refers to the rise of avg. mean temperatures in urban areas due to the effect of buildings, roads, and development on ambient local temperatures. It skews temperature data significantly for urban areas. Climatologists have to factor it out when trying to assess global warming.
The graph above helps isolate this effect by looking at the combination of satellite (atmosphere) and surface temperature readings over the last twenty years. Global warming apologists prefer surface data to atmospheric data (which doesn't need to be adjusted for the Heat Island Effect). This graph helps illustrate that any trace of a recent heating trend is isolated to the surface, and open to questions surrounding Heat Island and how it is accounted for.