This is one of the best demonstrations of climate change I've seen in a while. It vividly shows, as it moves from mostly cool blues in the 19th century to angry splotches of red in the 21st, both short blips in temperature and the much longer overall warming of the planet.
Some people tend to consider a particularly hot or cold day as evidence for or against global warming, which is a mistake. Global warming, as this video clearly demonstrates, is a long-term trend. And the accelerated warming we have experienced over the past 40 years has been, as the chief scientist behind the study says, "remarkable."
It's interesting to note that this map came out of research led by a Berkeley physicist, Richard Muller, who has been a vocal climate skeptic; the research was funded by the climate-skeptic Koch brothers. The evidence Muller compiled was so conclusive that he very publicly reversed his stand on climate change, writing in the Wall Street Journal last week, "Global warming is real. Perhaps our results will help cool this portion of the climate debate."
I urge you to watch this map animation, and pass it on.