Tuesday, 8 July 2014

Understanding adjustments to temperature data

by Zeke Hausfather

There has been much discussion of temperature adjustment of late in both climate blogs and in the media, but not much background on what specific adjustments are being made, why they are being made, and what effects they have. Adjustments have a big effect on temperature trends in the U.S., and a modest effect on global land trends. The large contribution of adjustments to century-scale U.S. temperature trends lends itself to an unfortunate narrative that “government bureaucrats are cooking the books”.


Figure 1. Global (left) and CONUS (right) homogenized and raw data from NCDC and Berkeley Earth. Series are aligned relative to 1990-2013 means. NCDC data is from GHCN v3.2 and USHCN v2.5 respectively.

Having worked with many of the scientists in question, I can say with certainty that there is no grand conspiracy to artificially warm the earth; rather, scientists are doing their best to interpret large datasets with numerous biases such as station moves, instrument changes, time of observation changes, urban heat island biases, and other so-called inhomogenities that have occurred over the last 150 years. Their methods may not be perfect, and are certainly not immune from critical analysis, but that critical analysis should start out from a position of assuming good faith and with an understanding of what exactly has been done.

This will be the first post in a three-part series examining adjustments in temperature data, with a specific focus on the U.S. land temperatures. This post will provide an overview of the adjustments done and their relative effect on temperatures. ...

Read more at Climate Etc.

(ht Hotwhopper)


  1. Nice post and explanation. I hope you're planing to reblogg future posts of this series since I do not plan to follow Curry's blog on a daily basis, though.

    In Argentina we have a saying that goes: "Es tirarle margaritas a los chanchos" which translates to "To cast pearls before swine" (apparently it has a biblical origin) and refers to offering something valuable to people who can't appreciate it.
    Reading the comments it seems obvious that that's what's happening. Curry's readers are impervious to explanations -no matter how transparent and well done- and they fall to their usual conspiracy mongering. The fact that "climategate" is mentioned right in the second comment is appalling.

  2. I will try to attend people to the next two instalments.

    It is probably a good idea not to read too much bad stuff. After a while you often do not know where you got a piece of information from, whether it was from a reliable source or not. That is one of the reasons why it is better to read HotWhopper as WUWT directly.


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