The Great Temperature Adjustment Flap

Matt Drudge has been riveting eyeballs by highlighting a London Telegraph piece calling the “fiddling” of raw temperature histories “the biggest science scandal ever.” The fact of the matter is some of the adjustments that have been tacked onto some temperature records are pretty alarming—but what do they really mean?

One of the more egregious ones has been the adjustment of the long-running record from Central Park (NYC). Basically it’s been flat for over a hundred years but the National Climatic Data Center, which generates its own global temperature history, has stuck a warming trend of several degrees in it during the last quarter-century, simply because it doesn’t agree with some other stations (which also don’t happen to be in the stable urban core of Manhattan).

Internationally, Cato Scholar Ross McKitrick and yours truly documented a propensity for many African and South American stations to report warming that really isn’t happening.  Some of those records, notably in Paraguay and central South America, have been massively altered.

At any rate, Chris Booker, author of the Telegraph article, isn’t the first person to be alarmed at what has been done to some of the temperature records.  Others, such as Richard Muller, from UC-Berkeley, along with Steven Mosher, were so concerned that they literally re-invented the surface temperature history from scratch. In doing so, both of them found the “adjustments” really don’t make all that much difference when compared the larger universe of data. While this result has been documented  by the scientific organization Berkeley Earth, it has yet to appear in one of the big climate journals, a sign that it might be having a rough time in the review process.

That’s quite different than what was found in 2012 by two Greek hydrologists, E. Steirou and D. Koutsoyiannis, who analyzed a sample of weather stations used to calculate global temperature and found the adjustments were responsible for about half of the observed warming, when compared to the raw data. Their work was presented at the annual meeting of the European Geosciences Union, but has not been published subsequently in the scientific literature. That’s not necessarily a knock on it, given the acrimonious nature of climate science, but it seems if it were an extremely robust, definitive paper, that it would have seen the light of day somewhere.

But, before you cry “science scandal” based upon the Greek results, it’s a fact that one of the adjustments that has been commonly used—taking into account the biases introduced by the time of day in which the high and low temperatures for the previous 24 hours are recorded—in fact does induce warming into most records, a change that in fact is scientifically justified.

In sum, I’d hold fire about “the biggest science scandal ever.” The facts are:

  • when the global temperature records were reworked by people as skeptical as yours truly, nothing much emerged;
  • some of the data have been mangled, like the Central Park record—and there are serious problems over some land areas in the Southern Hemisphere; and
  • some of the adjustments for measurement biases introduce scientifically defensible warming trends.