Thanks to Walter Williams for this one. You don't need me to recap, do you?
Here's the most important paragraph:
"The Coleman documentary presents research by computer expert E. Michael Smith and Certified Consulting Meteorologist Joseph D'Aleo. During the 1960s and into the 1980s, the number of stations used for calculating global surface temperatures was about 6,000. By 1990, the number of stations dropped rapidly to about 1,500. Most of the stations lost were in the colder regions of the Earth. Not adjusting for their lost made temperatures appear to be higher than was in fact the case. According to Science & Environmental Policy Project, Russia reported that CRU was ignoring data from colder regions of Russia, even though these stations were still reporting data. That means data loss was not simply the result of station closings but deliberate decisions by CRU to ignore them in order to hype their global warming claims. D'Aleo and Smith report that our NCDC engaged in similar deceptive activity where they have dropped stations, particularly in colder climates, higher elevations or closer to the polar regions. Temperatures are now simply projected for these colder stations from other stations, usually in warmer climates."
I still don't get why seemingly intelligent people fall for this, but history is replete with examples of that, right? Galileo was jailed, eugenics, the-moon-landings-were-faked crazies, these all spring to mind.