@Mosher
I know something is broken. I don’t need to isolate the cause in order to reach that conclusion.
Example. My car won’t start. That’s an observation. A fact. It would be nice to know why but the fact remains that it won’t start despite not knowing why it won’t start.
Adjustments to the entire temperature record add a warming trend. Stations singled out in a group that don’t need any adjustments don’t show the same warming trend. Something therefore isn’t working right in the adjustment process. That’s an observation. A fact. It would be nice to know what exactly is broken but I don’t have the time or expertise to figure out what’s wrong. My ignorance of the cause of the failure doesn’t change the fact that the adjustment process doesn’t work. I can make suggestions based on a casual investigation. I think the root cause is exactly what Watts et al are claiming – poorly sited stations are in the majority and they then become the “trusted” stations used to correct the minority of well sited stations.
But again for my purposes I don’t need to know why it doesn’t work. Sometimes you just scrap a car that won’t start and drive something else instead.
Write that down.
