Global warming alarmists purport to compute the average annual temperature over the entire surface of the Earth (most of which, of course, is ocean) to within one one-hundredth of a degree. That is, on its face, an unbelievable claim, but it becomes even more preposterous when you look at how temperatures are actually measured. A case in point comes from Anthony Watts.
Watts got a communication from Dr. Mark Albright, of the University of Washington:
Here is a great example of how NOT to measure the climate! On our way back to Tucson from Phoenix on Monday we stopped by to see the Picacho 8 SE coop site at Picacho Peak State Park. Note the white MMTS temperature monitor 1/3 of the way in from the left. The building is surrounded by the natural terrain of the Sonoran Desert, but instead the worst possible site adjacent to the paved road and SW facing brick wall was chosen in 2009 as the location to monitor temperature.
The wall and the road both radiate heat, artificially raising the temperature as recorded. That’s not all: air conditioning heat exchangers are located just a few feet away, constantly pumping out hot air:
I’m not saying the people who site temperature monitors locate them badly on purpose, but if you wanted to inflate temperatures artificially, this is one way you would do it. Nor is this station much of an anomaly: a majority of U.S. stations are poorly sited, which is just one of a number of issues with accurate and consistent temperature measurement. See, e.g., this study.
The more one learns about the surface temperature record, the more one concludes that satellite measurements are the only reliable, uncorrupted data set that we possess. Unfortunately, they go back only to 1979.