Where Do We Measure Surface Temperatures?

Evidence for global warming comes partially from surface readings taken at stations that don't often get moved, say because a parking lot was built next to them.

SurfaceStations.org has been cataloging these stations: over 2/3 of them are expected to give temperatures that more than 2 degrees centigrade too high - usually from a source of artificial heat located nearby.

The best examples are at the bottom of the page: a station that has been in the same field in Oakland for 130 years and shows declining temperatures versus a station in Marysvale, California, around which a parking lot and two air conditioning units have been built, which shows an increase of 3 degrees centigrade over the last 80 years.

Hmmm.