RealClimate? Those guys are as biased as they come regarding human-caused global warming. And they wasted no time downplaying the GISS adjustment. What other problems are lurking in the data? A sane, unbiased scientist, upon discovering one major problem in their datasets, would proceed to examine all other inputs for similar problems, instead of treating the problem data set as an outlier.
But that's what bias does to a scientist. It removes their objectivity. And science without objectivity is little more than propaganda.
Any perceived or real bias does not affect what is written in "The CO2 Problem in 6 Easy Steps". (Perhaps in the responses to comments, but not the actual article.) And this was only a sidebar to my post, anyway.
I agree with dirtboy's skepticism toward all the data sets. Not too long ago the stratosphere temperatures showed cooling and it was explained as something that would be expected from global warming. Then a correction in the bias was done to the data set and it showed the stratosphere temperatures to be warming and the scientists said that that was exactly what they had expected to see the stratosphere temperatures warming. Can't have it both ways.
I also see from the RealClimate link that they used a weighted formula for temperatures values to arrive at the "average" global temperature. I work in seismic processing and we deal with huge volumes of data and one of the holy grails is to "regularize" data sets and it involves much more than a simple weighted formula. In fact, there is no actual algorithm today in the seismic industry that is even close to 100% accurate and all the various algorithms are very data dependent.
I also have a problem with the concept of "climate sensitivity" being a value for a system in equilibrium when in fact the Earth is a non-equillibrum system in which temperature gradients drive the weather.
These are just random thoughts.