with the large and unwieldy daily temperature data files (even though most of them wouldln't have the slighest idea what to do with the data in the first place). This is just one more screwup to be added to a very long list of "climate skeptic" screwups. With respect to global-warming skepticism/denial, here is something that you can take to the bank. Any time a skeptic/denier claims that he/she has found some fatal flaw with some aspect of climate-science (whether it's alleged UHI contamination, "dropped stations" issues, hockey-sticks generated from random noise, etc.) you can be almost absolutely certain that the individuals making the claim "stepped in it" big-time somewhere. Some of the screwups are so obvious (like Spencer's population density screwup) that amateurs can flag the errors -- other screwups may require more advanced technical knowledge to recognize. But nonetheless, virtually every denier attack on any aspect of climate science that you can imagine is based on at least one (often embarrassing) screwup. A followup re: Spencer -- if he was trying to "back out" a temperature-trend to a "zero-population density" trend, then using zero-population-density as the baseline would be the thing to do. However, there's no physical basis for the claim that surface temperatures are extremely sensitive to population densities, especially when you consider that Spencer's "population density corrections" give you an answer that completely conflicts with the mid-tropospheric temperature trends derived from satellite data. The huge mismatch between the mid-tropospheric trends measured by satellites and the "population-density