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.
I would have to guess that in the opening sentence the “Climactic” in “U.S. National Climactic Data Center” is s typo, but please leave it. It’s a nice touch.
@Mosh
I should add that I presume no such ‘correction’ can or has been made, otherwise how can your observations be seen? Again, logically, if the correction/adjustment procedures are statistically and physically ‘sound’ – one would presume significant differences due to ‘number of stations’ should be relatively unnoticeable? Just asking……
Alarmists must loathe the satellite era, as there is much less opportunity to fiddle with the numbers.
But go back a century and anything goes, if the current trend continues we will soon find the LÍA ending around 1915.
Data rigging reaching a climax , more like.
This seems somewhat blown out of proportion, as its just a somewhat obscure product being updated. The primary NCDC U.S. (and global) temperature products are not changed; this simply brings an older series in-line with the main record through updating the data and analysis techniques.
For folks interested in diving into why adjustments are made, I’d suggest starting here: http://rankexploits.com/musings/2013/a-defense-of-the-ncdc-and-of-basic-civility/
People were also asking for the code used by NCDC in their pairwise homogenization algorithm. If can be found here: ftp://ftp.ncdc.noaa.gov/pub/data/ghcn/v3/software/52i/
Berkeley Earth’s code, which independently produces nearly identical CONUS-wide results, can be found here: http://berkeleyearth.org/analysis-code
Mosher 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.
….
No way, you simply can’t add more stations in the past, the past is gone.
Are you saying that the number of stations influences the “observed” data?
@Sean P Chatterton
Precisely. Orwell wrote in 1984 that those who control the present, control the past. Thus, history becomes rewritten according to the current needs of those in power.
To suggest that scientists of the early 20th were misreading thermometers by three degrees F is simply unsupportable. If there is a reason to believe there was a 3°F error that can be detected and corrected now the proper correction is to throw out the bad data. At the very least cease cocantation for the purpose of establishing trend.
Maybe I was thinking of this article:
Distorted data? Feds close 600 weather stations amid criticism they’re situated to report warming
August 13, 2013
http://www.foxnews.com/science/2013/08/13/weather-station-closures-flaws-in-temperature-record/
Zeke,
In your first link, you are linking to yourself blogging.
Are you asserting that you are an authority on this “obscure product”?
Are you officially connected with the product, or are you commenting as an objective observer?
Andrew
“I’m just trying to figure out why, when you look at those graphs as a whole, you can’t clearly see World War I, the Depression, or World War II. ”
Assuming you’re serious:
Understand that during the current 17 year “pause” in global warming, we’ve seen emitted into the atmosphere fully 25 percent of all the anthro Co2 produced since the beginning of industrial revolution. Expecting short term fluctuations of C02 to show up,,.,especially from a much lower baseline… is not realistic…despite all the simplistic (some might say propagandistic) talk about “control knobs.”
At 9:06 AM, pablo an ex pat says…
“and they expect to be credible, how exactly ?”
I’ll give you three ways:
1) How would you like to lose your job, today?
2) How would you like to be investigated by the IRS?, and
3) ‘We have found some irregularities in your medical records; you’ll notice these impacts January 2017.
That’s how.
I’d like to ask something, don’t know if it’s OK or not, hope it is. I love WUWT, think it’s extremely valuable, and I can’t begin to think how to properly express how grateful I am to Anthony Watts and how much I respect his work.
With that clear, I understand Steven Mosher’s argument. I haven’t heard the counter argument. Anthony, if you’ve got time, what do you make of this? Agree, disagree, indifferent? I guess what I’m getting at is, I understand Steven’s position. I haven’t heard anyone address why he’s wrong other than what I consider to be implausible arguments about his integrity or motivations.
I don’t know if I should have posted the question here or at Lucia’s. If it was rude to ask here, I apologize in advance and withdraw the question. At any rate, again, thanks so much for all you do and keep up the great work!
So does “adding more stations” to the past mean they’ve added the same stations they’ve since closed in the meantime? Or are these newly discovered past stations?
Andrew
OT
Just for fun on weather current. http://www.arapahoebasin.com/
Check out Current Conditions and view the Web Cams. 11%F , last three days 12″, new snow 4″, the managements comment ” its just like winter so we are going to stay open”.
Could anyone direct me to a link with the original data set (pre modified?) Where can I download that? Thanks Sher
I wanted to tell Trenberth that the reason for the “pause” was because they couldn’t eliminate the coldest weather stations any more–we’d catch them.
We caught this right away. That says they don’t think we can communicate this easily to the public at large.
The believers may be wrong, but they’ve had enough of a stranglehold on the press and public opinion to crash Western economies by sabotaging oil and coil and now fracking. This has killed myriads to millions of people by freezing and boiling people to death with high heating and air conditioning prices, and by the food riots we called “the Arab Spring.” It has also harmed wildlife enormously, by vilifying the basis of terrestrial Life (CO2) and by preventing ecologists from researching any harm that is going on by cheaply assigning it all to “global warming” or “climate change” and most of all by harming the economy. The wealth of a nation determines whether it can afford to invest in pollution controls, and how much.
It MATTERS–enormously–that we win the battle for public opinion.
Imo, the ways to do that are :
1. Follow the money. The least of it is the fact that the Koch brothers are a standing joke in our community. More importantly, the alarmists want YOUR money, thru taxes. Also important is that they crash your ability to pay any taxes.
2. WE are the scientists. The alarmists are POLITICIANS–Algore ran for President, remember? We also need to hit hard that IPCC stands for InterGOVERNMENTAL Panel on Climate Change. Anybody who ever took a college logic class knows that politicians lie 100% of the time. We can tell the public that the Null Hypothesis means that you don’t just make something up and consider it proven if it seems to make sense (Trenberth’s redefinition).
3. The Scientific Method is heavily under attack, which threatens all our well-being. See points 1 and 2, and then show them America’s NSF calls for research–very, very heavily weighted to “proving global warming.” The public may not understand science very well, and solving the hysteria will improve that, but showing them what the NSF has done to climate science is simple enough that they will “get it.”
4. Show the politicians–desperate for money–that what really gets more tax income is improving people’s economic freedom. AGW is counterproductive to them. Politicians like to communicate and are quoted in the lamestream controlled presses. They’re also a little smarter than average (with exceptions to be sure) and can understand our points a little ahead of the general public. But we have told them a little too much that the actual science is stable climate not warming. Money is where their heart is. Deal with that, and we’ll see a sea change in public opinion.
Auto-tumescence in numerology.
again, just saying
to get a global representative sample you must adhere to certain rules.
Nobody adheres to them…..not one global data set….
http://wattsupwiththat.com/2014/04/25/the-elusive-60-year-sea-level-cycle/#comment-1622942
Looks like as much fantasy as the Federal Budgets (which they also stopped publishing). Anyway even at their rate that’s less than 1 degree per human lifespan and I don’t think that’s a problem…
On Thursday, March 13, 2014,…..
…the NCDC said that all US temp records prior….were wrong
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.
Is the sky falling faster, now?
Mark, they will always find a way to adjust up….for UHI
Mosh’ 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.
===
How do you explain that ?
This necessarily means that the “more stations” are from a different distribution to the ones you already have included.
So what is it about the ones that were not used previously that causes the past to be cooler and present warmer. This is quite a surprising result that requires explanation. Not just “that’s way it is, your theory is busted”.