After the CRU-Hack and other pseudo-scandals of 2009, Berkeley physicist Richard Muller assembled a team of scientists and statisticians whose goal was to reanalyze land temperature records and determine once and for all whether factors such as the Urban Heat Island effect or the poor siting of surface stations had any discernible effect the long-term temperature increases that scientists have recorded in the U.S. and around the globe. In other words, they set out to determine whether the Earth was warming, or just our thermometers. Guess what? Its the Earth.
From their paper, Influence of Urban Heating on the Global Temperature Land Average Using Rural Sites Identified from MODIS Classifications:
As the captions indicate, this figure shows temperature readings for all stations versus a rural subset where the UHI effect should be absent. Had these two lines diverged significantly, this might have indicated scientists were mistakenly attributing temperature increases caused by UHIs to Global Warming. But they are almost identical.
From their paper, Earth Atmospheric Land Surface Temperature and Station Quality in the United States:
Koch brothers, and that Mr. Muller has made some rather sceptical, indeed intemperate remarks about Climate Science while at the same time displaying a very imperfect grasp of its tenets. But all that can be forgiven. In fact may add to the credibility of his project, at least in the eyes of the media. What is somewhat more disturbing is that Mr. Muller is getting tons of headlines for work that really just confirms what climatologists already knew years ago. For example, Anthony Watt's complaints about poorly placed (next to heat sources, for example) surface stations were answered back in 2007.