Over at Climate Skeptic, I have what could be called a climate Rorschach test. Look at these two images below. The left is the temperature plot for Lampasas, Texas, a station in the NASA GISS global warming data base. On the right is the location of the temperature station since the year 2000 (the instrument is in the while cylinder in the middle of the picture under the dish). Click either picture to expand
So here is the eye test: Do you read the warming since 2000 as man-made global warming due to CO2, or do you read it as a move of the temperature instrument to a totally inappropriate urban site to which the instrument was moved in 2000, contaminated with hot asphalt, car radiators, nearby buildings, air conditioning exhaust, etc?
You should know that NASA's GISS reads this as man-made global warming, and reports it as such. Further, NASA actually takes the raw data above and in their computer model lowers temperatures in 1900 and 1920, actually increasing the apparent warming trend. For the record, the GISS opposes this kind of photo survey as worthless and argues that their computer algorithms, which correct for urban warming at this site in 1900 but not in 2007, work just fine with no knowledge of the specific site location.