A short but salient video:
http://apod.nasa.gov/apod/ap130731.html
Jehanne, the "scientists" who earn their grants by promoting global warming been caught retroactively changing old graphs and charts of temperature changes. If you feed bogus data into a demonstration like that you get a pretty and scary demonstration but you don't prove anything.
http://stevengoddard.wordpress.com/2013/01/11/noaa-temperature-fraud-expands-part-1/There is huge money behind the global warming propaganda campaign, and the promoters of it keep doubling down on their propaganda when more and more things come out that discredit them.