while this won't end the global warming debate, you could hold out a faint hope that it might change the nature of the argument

The Berkely Earth project, a collaboration of a whole passel of extremely reputable climatologists, has issued a new set of findings regarding global temperature change over land for the past 100 years.  They used a statistical model that incorporated virtually every known data set, and came up with the following:

Their conclusions include the following:

• The urban heat island effect is locally large and real, but does not contribute significantly to the average land temperature rise. That's because the urban regions of Earth amount to less than 1% of the land area.

• About 1/3 of temperature sites around the world reported global cooling over the past 70 years (including much of the United States and northern Europe). But 2/3 of the sites show warming. Individual temperature histories reported from a single location are frequently noisy and/or unreliable, and it is always necessary to compare and combine many records to understand the true pattern of global warming.

• The large number of sites reporting cooling might help explain some of the skepticism of global warming," Rohde commented. "Global warming is too slow for humans to feel directly, and if your local weather man tells you that temperatures are the same or cooler than they were a hundred years ago it is easy to believe him." In fact, it is very hard to measure weather consistently over decades and centuries, and the presence of sites reporting cooling is a symptom of the noise and local variations that can creep in. A good determination of the rise in global land temperatures can't be done with just a few stations: it takes hundreds -- or better, thousands -- of stations to detect and measure the average warming. Only when many nearby thermometers reproduce the same patterns can we know that the measurements were reliably made.

• Stations ranked as "poor" in a survey by Anthony Watts and his team of the most important temperature recording stations in the U.S., (known as the USHCN -- the US Historical Climatology Network), showed the same pattern of global warming as stations ranked "OK." Absolute temperatures of poor stations may be higher and less accurate, but the overall global warming trend is the same, and the Berkeley Earth analysis concludes that there is not any undue bias from including poor stations in the survey.

Now there are two important things about this survey:  (1) it doesn't imply a cause for such warming; in fact the data on urban islands would tend to argue against androgynous global warming; and (2) the authors are quite forthright both about the (a) impact of "poor" stations and the fact that (b) data from the oceans reduce the overall global temperature increase.

They even acknowledge that a major part of the perception problem is that the US and Europe have been experiencing cooling during that period--which has been called for (and ignored) by most skeptics.

I realize this will not be the last word on the subject; it is not intended to be.

But maybe the care with which they have selected and processed the data will take some of the steam out of attacks on "scientists manipulating the data" or "bunch of capitalism-hating commies trying to change our society" BS.

Then again, probably not.