Guest essay by Dan Travers
On Thursday, March 13, 2014, the U.S. National Climactic Data Center switched to gridded GHCN-D data sets it uses to report long term temperature trends – with a resulting dramatic change in the official U.S. climate record. As seems to always happen when somebody modifies the temperature record, the new version of the record shows a significantly stronger warming trend than the unmodified or, in this case, discarded version.
The new dataset, called “nClimDiv,” shows the per decade warming trend from 1895 through 2012 for the contiguous United States to be 0.135 degrees Fahrenheit. The formerly used dataset, called “Drd964x,” shows the per decade warming trend over the same period to be substantially less – only 0.088 degrees. Which is closer to the truth?
As will be illustrated below in the side by side comparison graphs, the increase in the warming trend in the new data set is largely the consequence of significantly lowering the temperature record in the earlier part of the century, thereby creating a greater “warming” trend.
This particular manipulation has a long history. For an outstanding account of temperature record alterations, tampering, modifications and mutilations across the globe, see Joseph D’Aleo and Anthony Watts’ Surface Temperature Records: Policy-Driven Deception?
It should be noted that the 0.088 degree figure above was never reported by the NCDC. The Center’s previous practice was to use one data set for the national figures (nClimDiv or something similar to it) and a different one for the state and regional figures (Drd964x or something similar). To get a national figure using the Drd964x data, one has derive it from the state data. This is done by taking the per decade warming trend for each of the lower forty-eight states and calculating a weighted average, using each states’ respective geographical area as the weightings.
The chart below shows a state by state comparison for the lower forty-eight states of the per decade warming trend for 1895-2012 under both the old and the new data sets.
In the past, alterations and manipulations of the temperature record have been made frequently and are often poorly documented. See D’Aleo and Watts. In this instance, it should be noted, the NCDC made considerable effort to be forthcoming about the data set change. The change was planned and announced well in advance. An academic paper analyzing the major impacts of the transition was written by NOAA/NCDC scientists and made available on the NCDC website. See Fenimore, et. al, 2011. A description of the Drd964x dataset, the nClimDiv Dataset, and a comparison of the two was put on the website and can be see here.
The relative forthcoming approach of the NCDC in this instance notwithstanding, looking at the temperature graphs side by side for the two datasets is highly instructive and raises many questions – the most basic being which of the two data sets is more faithful to reality.
Below are side by side comparisons under the two data sets for California, Maine, Michigan, Oregon and Pennsylvania for the period 1895-2009, with the annual data points being for the twelve month period in the respective year ending in November. The right-side box is the graph under the new nClimDiv dataset, the left-side box is the graph for the same period using the discarded Drd964x dataset. (The reason this particular period is shown is that it is the only one for which I have the data to make the presentation. In December 2009, I happened to copy from the NCDC website the graph of the available temperature record for each of the lower forty-eight states, and the data from 1895 through November 2009 was the most recent that was available at that time.)
I will highlight a few items for each state comparison that I think are noteworthy, but there is much that can be said about each of these. Please comment!
California
Left: Before, Right: After – Click to enlarge graphs
- For California, the change in the in datasets results in a lowering of the entire temperature record, but the lowering is greater in the early part of the century, resulting in the 0.07 degree increase per decade in the Drd964x data becoming a .18 degree increase per decade under the nClimDiv data.
- Notice the earliest part of the graphs, up to about 1907. In the graph on left, the data points are between 59 and 61.5 degrees. In the graph on the right, they are between 56 and 57.5 degrees.
- The dips at 1910-1911 and around 1915 in the left graph are between 57 and 58 degrees. In the graph on the right they are between 55 and 56 degrees.
- The spike around 1925 is above 61 degrees in the graph on the left, and is just above 59 degrees in the graph on the right.
Maine
· The change in Maine’s temperature record from the dataset switch is dramatic. The Drd964x data shows a slight cooling trend of negative .03 degrees per decade. The nClimDiv data, on the other hand, shows a substantial .23 degrees per decade warming.
· Notice the third data point in the chart (1898, presumably). On the left it is between 43 and 44 degrees. On the right it is just over 40 degrees.
· Notice the three comparatively cold years in the middle of the decade between 1900 and 1910. On the left the first of them is at 39 degrees and the other two slightly below that. On the right, the same years are recorded just above 37 degrees, at 37 degrees and somewhere below 37 degrees, respectively.
· The temperature spike recorded in the left graph between 45 and 46 degrees around 1913 is barely discernable on the graph at the right and appears to be recorded at 41 degrees.
Michigan
- Michigan’s temperature record went from the very slight cooling trend under Drd964x data of -.01 degrees per decade to a warming trend of .21 degrees per decade under nClimDiv data.
- In Michigan’s case, the differences between the two data sets are starkly concentrated in the period between 1895 and 1930, where for the entire period the temperatures are on average about 2 degrees lower in the new data set, with relatively modest differences in years after 1930.
Oregon
· Notice the first datapoint (1895). The Drd964x dataset records it at slightly under 47.5 degrees. The new dataset states at slightly over 45 degrees, almost 2.5 degrees cooler.
· The first decade appears, on average, to be around 2.5 degrees colder in the new data set than the old.
· The ten years 1917 to 1926 are on average greater than 2 degrees colder in the new data set than the old.
· As is the case with California, the entire period of the graph is colder in the new data set, but the difference is greater in the early part of the twentieth century, resulting in the 0.09 degrees per decade increase shown by the Drd984x data becoming a 0.20 degree increase per decade in the nClimDiv data.
Pennsylvania
· Pennsylvania showed no warming trend at all in the Drd964x data. Under the nClimDiv data, the state experienced a 0.10 degree per decade warming trend.
· From 1895 through 1940, the nClimDiv data shows on average about 1 degree colder temperatures than the Drd964x data, followed by increasingly smaller differences in later years.
Mark Bofill says
April 29, 2014 at 9:53 am: [ “…” ]
Mark, are you advocating censorship?
I don’t think so. But if people can’t express their views, that’s what it amounts to.
Steve Mosher has his opinions, some of which I agree with. But I disagree with his idea that he, or anyone else, should be the gatekeeper of the debate. Who gets to draw the line? Who do we exclude? WUWT got very popular by allowing all points of view. Alarmist blogs censor skeptics, and as a result their traffic is pathetic.
I agree with you about S. Goddard, too. He is every bit as sincere and ethical as Mosher, or anyone on the skeptic side [skeptics are the only honest kind of scientists, BTW]. To label Goddard’s point of view as “conspiracy crap”, and to tell folks they should not read Lord Monckton, is a reflection on Steven Mosher, not on them.
Mark Albright says:
April 29, 2014 at 10:12 am
The reason the entire record cools is NCDC is now adding an adjustment for elevation. There is a sampling bias towards low elevation sites, since that is where most people reside and take weather observations. Cooler high elevation sites are under-sampled, so they are attempting to adjust for that, hence a lower temperature.
====
Sounds like a plausible explanation but I did not see that mentioned , where do you find this information?
You know what they say, “If you can’t beat ’em then cheat ’em”.
Which roughly translated says that every time you feel you are losing the AGW argument just make the data more extreme. Science, honesty and objectivity be damned.
@Zeke Hausfather
Thanks! The link is broken right now, but I think that’s a problem at NOAA. I’ll grab the software when it is available.
Indeed – I’d saved the earlier plot for CA, and had recently run it again on the site, as the rhetoric was heating up out here about our current drought cycle.
I’d ask the author, or Anthony – can you guys improve on the quality of the graphics here (and preferably such that the before and after image, appear in one single file) such that readers can more easily save the graphics for our future efforts to share these examples with others.
The best way to catch others attention here is to be able to shoot a quick email off to someone who’s blaming it all on AGW. I even have a habit of printing out a good graphic – like these examples – and keeping it in my wallet. We’ll be out at dinner with folks, and someone will bring up how we’re causing CA to cook because of ACC. I’ll pull it out of my wallet and say, “perhaps it’s not even true,” while handing them the graphic.
It works wonders.
Sherry Moore says:
Could anyone direct me to a link with the original data set (pre modified?) Where can I download that? Thanks Sher
ftp://ftp.ncdc.noaa.gov/pub/data/cirs/drd/
DBStealey,
No! Quite the opposite. I think Steven’s correct in this.
The trouble is, of course I’d think Steven’s correct in this. I’ve heard his argument, and I haven’t invested the time that he or AW has in investigating temperature records. What I’m really asking is, does anyone I respect have any good counterarguments that I haven’t heard. Just trying to be a good skeptic. Having heard why Steven thinks he’s right, why is Steven wrong?
DBStealey,
I’m a little alarmed that you thought I was advocating censorship. Nothing could be further from my mind. I guess I missed something in the comment I linked, or phrased something poorly? It wouldn’t be the first time I’d proven myself to be a careless dumb-ass. Still, if this is the case if you could point me to it I’d be grateful behind my embarrassed blush. 🙂
Oh. I understand what you’re saying now Stealey.
TY.
Just a minor adjustment of the temperature record to better fit the CO2 record. What’s the problem!
The problem is that is doesn’t better fit the CO2 record. The slope is steeper prior to 1950. But it is not until 1950 that CO2 becomes a significant player. So it actually supports the “recovery from the LIA by unknown mechanism” theory.
“Just trying to be a good skeptic”
Mark B,
The first step in being a good skeptic is to not just take someone’s word for something. So, if someone on the internet says:
“A) when you add more stations, you will find the past is cooler than previously estimated.
B) when you add more stations, you will find that the present is warmer than you think.”
You should require that they provide all the evidence that is relevant to their assertion, or conclude it’s mere assertion.
In the case of the above, we can conclude it’s just assertion, since no relevant evidence has been provided.
Andrew
They can modified the temperature data all they want. What they can’t change is the physical property of water that it freezes at 32 degrees F. Thus the day will come when the claims of record heat will conflict with the observation that it is snowing and the lakes are still frozen. Then what?
We’ve gone from “Hide the Decline” to “Ride the Incline.”
Maybe we just need to add more “high elevation” stations in the present to get everything just right…
And, how does one add a high elevation station in the past if it wasn’t there to begin with?
For the past couple of years NCDC has even had a comparison tool available online so that folks could compare the old divisional values with the new ones:
http://www.ncdc.noaa.gov/temp-and-precip/divisional-comparison/
More details on the new method of calculation based on a 5-km grid approach can be found here:
http://www.ncdc.noaa.gov/monitoring-references/maps/us-climate-divisions.php
My eyes opened up when out of the blue, 1934 was adjusted down from the hottest year on record with little or no explaination. Hence, 1998 could take the top spot.
Don’t get me wrong, I have little confidence in any of the temp sets based on surface obs. The US based record sets are poor, but they are considered the best globally. They can’t be cured through adjustment or concatenation theory.
Bad Andrew,
I’m willing to wager within reason that Steven Mosher has been transparent with BEST, and that if I cared to spend the time, I’d find the data on which he bases his assertions. To save time, for the sake of argument I assume Steven isn’t B.S.ing me. I can always check later.
Thanks.
This is interesting.
Of the 119 entries there are only 28 which represent an Above Normal or Much Above Normal value for Contiguous United States Annual Temperature Anomalies (1981-2010 Base Period).
http://www.ncdc.noaa.gov/monitoring-references/maps/us-climate-divisions.php
Much Above Normal anomalies are found in, among others, 1921, 1931, 1934, and 1953.
Climatological Ranking Definition
http://www.ncdc.noaa.gov/monitoring-references/dyk/ranking-definition
Steven Mosher;
I have to admit to considerable confusion on your explanation. Perhaps there’s something I am missing, or perhaps the matter just exceeds my mental capabilities. But I distinctly recall you saying, on multiple occasions, that station drop out doesn’t change anything. That fewer stations gave the same answer as more stations. I simply cannot reconcile those statements with your current position which seems to be that adding stations does affect things. If so, then removing stations should not.
Could you please explain how you can stand by both positions at the same time?
Greg says:
April 29, 2014 at 8:46 am
Sure they can. We can safely predict that in the next few years the past will get colder.
This is obvious from the lack of warming or “pause”. Since there is no warming this decade, the effect of GHG forcing is to make the past cooler.
You have no grasp on how climatolgy works, Where have you been ???
————————-
But a few years after that, they’ll adjust it again, making their previous prediction of the past incorrect. Every time they adjust the data, they prove that their previous predictions of what already happened was incorrect.
“I assume Steven isn’t B.S.ing me.”
Then you are not a skeptic. Or science-minded for that matter.
Andrew
This new method of deriving temperatures appears to completely eliminate CO2 as a climate driver. The graphs shown seem to indicate that, since temperatures have been on a fairly steady upward trend since 1895, long before large amounts of CO2 were emitted by industry and transportation, there is less evidence that man-produced CO2 had much if anything to do with the increase in temperatures (at least in the US). If temperatures rose dramatically from 1895 to 1940, as the graphs indicate, with no possible connection to CO2, why then does the increase after 1940 need to be attributed to CO2, and why is the increase before 1940 were apparently at least as rapid, or more rapid, than after 1940? (I was unable to download anything from NOAA, so my observation is based on the graphs above and therefore based on limited input)
Bad Andrew,
Let’s assume that you’ve demonstrated that your cock is larger than mine. OK, I’m not science minded or a skeptic. Are we good now?
Sorry, you need to click on the Drd964x vs. nClimDiv link when you get to the http://www.ncdc.noaa.gov/monitoring-references/maps/us-climate-divisions.php apge.
My previous comment was based on the Drd964x vs. nClimDiv data.
davidmhoffer says
http://wattsupwiththat.com/2014/04/29/one-way-adjustments-the-latest-alteration-to-the-u-s-climate-record/#comment-1624613
henry says
Mr Mosher is famous for not answering to any challenge
he just disappears whenever he is challenged
It’s simply amazing how EVERY “error” they find in the record always seems to require cooling the past and warming the present. If someone flipped a coin ‘heads’ 10 times in a row I think I’d have already asked that someone else do the tossing with a new coin and do it where everyone can see it.