Analysis of Temperature Change using World Class Stations

Guest essay by Ron Clutz

This is a study to see what the world’s best stations (a subset of all stations I selected as “world class” by criteria) are telling us about climate change over the long term. There are three principle findings.

To be included, a station needed at least 200 years of continuous records up to the present. Geographical location was not a criterion for selection, only the quality and length of the histories. 247 years is the average length of service in this dataset extracted from CRUTEM4. 

The 25 stations that qualified are located in Russia, Norway, Denmark, Sweden, Netherlands, Germany, Austria, Italy, England, Poland, Hungary, Lithuania, Switzerland, France and Czech Republic. I am indebted to Richard Mallett for his work to identify the best station histories, to gather and format the data from CRUTEM4.

The Central England Temperature (CET) series is included here from 1772, the onset of daily observations with more precise instruments. Those who have asserted that CET is a proxy for Northern Hemisphere temperatures will have some support in this analysis: CET at 0.38°C/Century nearly matches the central tendency of the group of stations.

1. A rise of 0.41°C per century is observed over the last 250 years.

Area WORLD CLASS STATIONS
History 1706 to 2011
Stations 25
Average Length 247 Years
Average Trend 0.41 °C/Century
Standard Deviation 0.19 °C/Century
Max Trend 0.80 °C/Century
Min Trend 0.04 °C/Century

The average station shows an accumulated rise of about 1°C over the last centuries. The large deviation, and the fact that at least one station has almost no warming over the centuries, shows that warming has not been extreme, and varies considerably from place to place.

2. The warming is occurring mostly in the coldest months.

The average station reports that the coldest months, October through April are all warming at 0.3°C or more, while the hottest months are warming at 0.2°C or less.

Month °C/Century Std Dev
Jan 0.96 0.31
Feb 0.37 0.27
Mar 0.71 0.27
Apr 0.33 0.28
May 0.18 0.25
June 0.13 0.30
July 0.21 0.30
Aug 0.16 0.26
Sep 0.16 0.28
Oct 0.34 0.27
Nov 0.59 0.23
Dec 0.76 0.27

In fact, the months of May through September warmed at an average rate of 0.17°C/Century, while October through April increased at an average rate of 0.58°C/Century, more than 3 times higher. This suggests that the climate is not getting hotter, it has become less cold..

3. An increase in warming is observed since 1950.

In a long time series, there are likely periods when the rate of change is higher or lower than the rate for the whole series. In this study it was interesting to see period trends around three breakpoints:

  1. 1850, widely regarded as the end of the Little Ice Age (LIA);
  2. 1900, as the midpoint between the last two centuries of observations;
  3. 1950 as the date from which it is claimed that CO2 emissions begin to cause higher temperatures.

For the set of stations the results are:

°C/Century Start End
-0.38 1700’s 1850
0.95 1850 2011
-0.14 1800 1900
1.45 1900 1950
2.57 1950 2011

From 1850 to the present, we see an average upward rate of almost a degree, 0.95°C/Century, or an observed rise of 1.53°C up to 2011. Contrary to conventional wisdom, the aftereffects of the LIA lingered on until 1900. The average rate since 1950 is 2.6°C/Century, higher than the natural rate of 1.5°C in the preceding 50 years. Of course, this analysis cannot identify the causes of the 1.1°C added to the rate since 1950. However it is useful to see the scale of warming that might be attributable to CO2, among other factors.

Of course climate is much more than surface temperatures, but the media are full of stories about global warming, hottest decade or month in history, etc. So people do wonder: “Are present temperatures unusual, and should we be worried?” In other words, “Is it weather or a changing climate?” The answer in the place where you live depends on knowing your climate, that is the long-term weather trends.

Note: These trends were calculated directly from the temperature records without any use of adjustments, anomalies or homogenizing. The principle is: To understand temperature change, analyze the changes, not the temperatures.

Along with this post I have submitted the World Class TTA Excel workbook for readers to download for their own use and to check the data and calculations. You can download it from this link: World Class TTA (.xls)

For those who might be interested, the method and rationale are described at this link, along with the pilot test results on a set of Kansas stations:

http://wattsupwiththat.com/2014/07/12/a-way-of-calculating-local-climate-trends-without-the-need-for-a-government-supercomputer/

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Dave

Be interesting to see graphical representations…..

Howsmart

1.1c per century sounds about right for co2 doubling.

Two more categories would be of use:
1. 1979 to present – to compare to the satellite record
2. 1998 to present – to compare to “the pause”
I expect the record will deviate from the satellite record due to UHI and siting issues. By how much would be of as much interest as the actual trend reported itself.

Richard Mallett

Reply to Dave :-
I suggested this to Ron, but also mentioned that this blog may not be the best medium for that, because there are 25 stations, 12 months, and annual trends, so that could be 325 graphs. What would you like to see ? I have plotted the annual average anomalies from the 1961-1990 average for each station.

Interesting, but what does it really mean?
Surely, the 25 stations were all located in urban areas that produced more high rises, electric heaters, etc. etc. over time?
Who knows what happened in fields and woods 1/4 mile plus from the nearest roads in the same nations at the same time?

[snip – your comment makes no sense as posted. If you have a point, make it. Drive by comments consisting of one line Mosherisms add nothing to the conversation. You are welcome to re-submit a comment of substance. – Anthony]

Richard Mallet;
What would you like to see ? I have plotted the annual average anomalies from the 1961-1990 average for each station.
>>>>>>>>>>>>>>>>>>
Just average them for the time being, just like you did in the table.

“The Central England Temperature (CET) series is included here from 1772, the onset of daily observations with more precise instruments. Those who have asserted that CET is a proxy for Northern Hemisphere temperatures will have some support in this analysis: CET at 0.38°C/Century nearly matches the central tendency of the group of stations.”
CET is not a station. it has been adjusted and homogenized.
now people will defend using adjusted data. crutemp4 is adjusted and homogenized. CET is likewise.
Here is a clue.
Dont use monthly data as your source.
Dont use “regional series” as your source.
and dont believe that “long stations” are necessarily the best. doubt everything

TobiasN

But if there a temperature station that’s been around for 247 years, then it’s probably in a city that has grown all this time, right?

Richard Mallett

Reply to davidmhoffer :-
For my list of 28 best stations (Ron dropped one of each pair of stations from the same location) the annual trend from 1979-2010 (the limit of CRUTem4) is +4.78 C/century and from 1998-2010 is -1.77 C/century.

JohnB

“The average rate since 1950 is 2.6°C/Century, higher than the natural rate of 1.5°C in the preceding 50 years. Of course, this analysis cannot identify the causes of the 1.1°C added to the rate since 1950. However it is useful to see the scale of warming that might be attributable to CO2, among other factors.”
– You assume the “natural rate” of 1.5°C would have continued and that therefore the rate attributable to CO2 is 1.1°C. What is the justification for that?

chemman

Howsmart says:
July 28, 2014 at 9:40 am
—————————————————————————————————————————
The only problem is that the CO2 hasn’t even doubled yet over the period this is talking about. So there is something more going on than changes in the [CO2].

Richard Mallett

Reply to davidmhoffer :-
I don’t know how to post images on here. Maybe Ron does.
[Reply: Only those with Edit privileges can post images. But you can post the image address, or link to an image. ~mod.]

njsnowfan

Great report and info.
At first glance, the temperature increases seem match increases in solar activities from the period.
Now we need someone to compair this data with true sunspot data in a well laid out chart( not my Art Charts).
Also I know you say they are world class stations but what is the human population growth surrounding the stations and what % of the area surrounding them has been built up with buildings, homes and Black Pavement. Were the areas with less population growth, new buildings, homes and Paved surfaces with more or less of temperature increase.
.

Richard Mallett

Reply to njsnowfan :-
Where can I find population data from 1700 to the present for individual locations ?

Ron Clutz

Thanks Anthony.
We knew CET relies on more than one station, but was included because it is a well-respected long record. As it turns out, removing it would change little, since it mirrors the central tendency.
I share Mosher’s distrust of data averages, and intend to look at Tmaxs and TMins. As for regional series, did not Mosher himself once say that 10 long station records would give approximately the same result as that from all records?

more soylent green!

The warming is mostly in the winter — oh the horror!

Mr. Clutz,
You have done good and valuable work here. Urban Heat Island effects have been shown, in the USA at Las Vegas, to explain as much as 3 degrees C spurious temperature increases since the 1950’s. If there were an easy way to pick a rural station associated geographically with each of your All-Star 25, perhaps with a continuous record of several decades back from present, it seems that your analysis could be made even more valuable.
Your 2.57 C increase 1950-2011 would not seem plausible absent UHI effects, any thoughts?
I appreciate your contribution…

Antero Järvinen

Stockholm and Uppsala (Sweden) are close to each other. Stockholm is a large city, Uppsala a small town. Compare the results (trends, etc.)! Best from Finland, Antero Jarvinen

Richard Mallett

Reply to Antero Jarvinen :-
Overall, Uppsala has an annual trend of +0.10C per century.
Stockholm +0.28 C per century.
Stockholm Bromma (shorter record, not used by Ron) +0.33 C per century.

njsnowfan

“Richard Mallett says:
July 28, 2014 at 10:10 am
Reply to njsnowfan :-
Where can I find population data from 1700 to the present for individual locations ?”
I have no idea where to find that data. The influence is most likely small but would like to see what the % is.
Solar activity since the end of the last mini ice age is in line with the data and the strongest solar cycles ever recorded is also in line with the sharper increase since 1950.

JohnnyCrash

All of those stations are in cities, so couldn’t UHI could be even larger than 2.57 C. TOBS? Calibration? Station movement? Thermometer changes? etc etc etc.
I don’t think anything can be learned from any of the ground based temperature records. Obviously a lot of $$ can be gained though…

Eliza

So its 0.41C per CENTURY (100 years) so probably insignificant either way. Why hasn’t 2012, 2013 and 2014 been included?Thanks for your efforts BTW.

Richard Mallett

Reply to Eliza :-
Only because the latest years are not in CRUTem4.

Richard Mallett says:
July 28, 2014 at 10:00 am
Reply to davidmhoffer :-
For my list of 28 best stations (Ron dropped one of each pair of stations from the same location) the annual trend from 1979-2010 (the limit of CRUTem4) is +4.78 C/century and from 1998-2010 is -1.77 C/century.
>>>>>>>>>>>>>>
Well that’s interesting. That 1979 to 2010 is well above satellite, but 1998 to 2010 is well below. I expected the first result due to UHI but the second result baffles me. If they were commensurate with one another, you’d have something of interest for the longer record of the ground stations. But since you don’t, I’m not sure that the record is of use unless you can figure out what the driving factors are in the disparities, and then (dreaded word though it is) adjust accordingly.

Richard Mallett

Reply to davidmhoffer :-
Inevitably, the stations with the longest (and most complete) temperature records are all in Europe, so we cannot extrapolate to the rest of the world.

Mosher,
The objections here to “adjusted” data, mine included, are based on traditional scientific/engineering standards. Data revision with no political agenda, properly done, is not objectionable. Clearly our current Federal government functionaries have their thumbs on the scale, as Steyer and his ilk have instructed the Dem lackeys in Washington to do.
I just looked at Moshtemp, to get some idea of who you are and why you do what you do. Have you become lost in the trees, no longer able to see the forest? Your defense of BEST methods, while ignoring the political machinations behind them, is disingenuous at best. There is a word an English PhD could appreciate!
Odd that you lecture Mr. Clutz as if he, and all of us, are your students. Not so much…

Ron Clutz

Reply to Michael Moon:
No doubt most of these stations are in urban heat islands, many of them located at airports. As we know, it’s the changes in air traffic, population density, buildings, pavement, etc that impacts upon temperature changes.
One clue is CET, a mixture of rural and urban sites, shows the following:
1900-1950 +1.32C/Century
1950-2014 +1.66C/Century

Antero Järvinen

Reply to Richard Mallet: Yes, I noticed the difference, too, and made some graphs. A big difference between these neighboring towns, and a small trend in both of them. Antero

Alec aka Daffy Duck

“Of course, this analysis cannot identify the causes of the 1.1°C added to the rate since 1950.”
Layman here… All the sites are in Europe, does AMO influence temps in Europe? I believe AMO was at a low point in 1950 and a high point in 2011

Steven Kopits

Almost all of these are in urban areas and should be subject to at least some UHI effect.

ES

You can make your own chart to match what data you want, with the spread sheet provided.
Select the years you want (column C) hold the ctrl key and select the temperatures you want that match the years. The select insert > scatter chart and select the one you like.
You have to enable editing first and get full ribbon – the little arrow beside the blue ?.
If you need help – Google is your friend:
http://office.microsoft.com/en-ca/excel-help/add-or-remove-titles-in-a-chart-HP010342154.aspx

Michael D

The Stockholm comparison underscores the Urban Heat Island influence.
I wonder if there are comparable data from somewhere outside of Europe. e.g. China?

Richard Mallett

Reply to Michael D :-
All the long temperature records without major gaps in the annual record are in Europe.
In China, Beijing starts in 1841, and only has 116 years (68%) with complete data.
Shanghai starts in 1847, and has 138 out of 165 years (84%) with complete data.
For me, that’s not enough coverage of the pre-industrial period.

Greg Goodman

“Note: These trends were calculated directly from the temperature records without any use of adjustments, anomalies or homogenizing. ”
Where did you get that idea from ??!
http://onlinelibrary.wiley.com/doi/10.1029/2011JD017139/abstract;jsessionid=DC740DACE56ABD9B9BAEA0440C44FA80.f01t03
“This study is an extensive revision of the Climatic Research Unit (CRU) land station temperature database…. Many station records have had their data replaced by newly homogenized series that have been produced by a number of studies”

Ron C.

E.S., thanks for that tip;Richard is more of a graphics than I am, but this is useful.
Daffy, Don’t know about AMO effects upon N. Europe. One surprise for me was to see how slow was the recovery from the LIA; I now question whether that was a steady rise.

This article like several others has noted the issue of “Less Cold”.
I have been plotting certain Western Canadian stations downloaded from Environment Canada for my own interest. I picked places I know and for diverse local climate. The issue of getting “LESS COLD” shows up in every plot I have done so far. I like to look at Max Extremes versus Min Extremes along with Max Monthly Means and Min Monthly Means. In all the sites I have looked at, it seems the temperatures are getting “less” extreme with highs getting lower or staying the same and lows getting higher. The “average” of course shows increasing temperatures even where the max declines because the minimums are less cold. EC also provided precipitation – and that looks like a sine curve so I suspect Western Canada precipitation is affected by the oscillations of the Pacific and the Jet stream (no surprise there). Of course, in Western Canada I can only get 60 to 110 years of data, and the longer series often have holes in them. The trends however, hold across the breaks. The technical aspects of this can be argued infinitum.
But I am curious about the “Less Cold” aspect of this warming as I am seeing it commented on more frequently. Just like less cold night time temperatures affects daily averages/means. it would seem less heat is being radiated out at night and when it is cold. Undoubtedly there are people here with ideas as to why the earth seems to be modulating temperature/heat in this way? And if you do, please do away with the formulae for radiative heat transfer and black body discussions and see if you can put it into lay terms.
Thanks.
Examples:
Trends are picked from graphed trend line.
Bella Coola, west coast of BC, on the Ocean, 107 years of record, Mean monthly trend + 1C;
Monthly Extreme Max – no trend, Monthly Extreme Min +2.5C
Rocky Mountain House, AB Lee of Rocky Mountains. 90 years of record, Mean monthly trend +1C;
Monthly Extreme Max -0.5C, Monthly Extreme Min +5C;
Monthly Mean Max -1, Monthly Mean Min +2C
Grand Forks, BC – Desert – highs close to 40, 67 years of record, Mean Monthly trend +1C:
Monthly Extreme Max -1.2C, Monthly Extreme Min +2.5
Monthly Mean Max -0.5+-, Monthly Mean Min +2.5

Ron C.

Greg Goodman
Yes, there is a fine line between quality control of errors, and tampering. The studies mentioned are done by NMSs, who are the people producing, verifying and submitting the data. I tend to believe they are trying to get the record right.

david dohbro

Excellent analysis. Do you maybe observe a ~60 yr oscillation in these data? E.g. high at ~1876, low at 1911, high at 1945, low at 1976, high at 2007?
thanks!

Richard Mallett

Reply to David Dohbro :-
I don’t see that in my annual average anomalies. I see (roughly) a gradual climb from 1894 to 1942, a decline to 1990, followed by an increase.

Oh, I should have mentioned all the monthly processed data I seem to be able to find in CSV format on the Environment Canada Site seems to end in 2007 at present so that is what I used.

Robert W Turner

Perhaps in part or mostly due to an increase in relative humidity during the winter? Is data on humidity and dew point collected and retained at these weather stations?

Ron C.

Wayne Delbeke
You have a colleague in J.R. Wakefield. If you have not yet seen this:
http://www.scribd.com/doc/25338819/What-Does-Averge-Temperature-Actually-Mean

If you don’t want to use CET, you can use the Oxford Radcliffe Observatory, which dates back to 1815.
http://www.geog.ox.ac.uk/research/climate/rms/meanair.html
Again, this will be highly subject to UHI.

Greg Goodman

” crutemp4 is adjusted and homogenized. CET is likewise.”
This needs correcting in the article. It is a signifant error and likely to mislead may readers.
“Dont use monthly data as your source.
Dont use “regional series” as your source.
and dont believe that “long stations” are necessarily the best. doubt everything”
Indeed. There is not reason to assume a long record is accurate long term. They are very likely to be affected by UHI effect.
Also I see Kremsmunster Hohenpissenberg and other HISALP stations. Their long term variation is nothing but “bias corrections”. Most of them were pretty flat before they got “corrected” and homogenised.
You really need to research your sources better before playing with your spreadsheet.
Clearly you have not even checked wether these data are adjusted or not before incorrectly assuring everyone they are not.
No cookie. 🙁

Greg Goodman

Anthony, could you look at this incorrect statement that these data are not adjusted / homgenised. It is grossly misleading and needs correcting in the article.
[I’ll check with the author -A]

Laurence Clark Crossen

Re: “This suggests that the climate is not getting hotter, it has become less cold.”
Actually, this is well established as due to heat transport, which distributes the warming more to the colder parts of the year and colder parts of the globe.

Ron C.

Michael Moon and others interested in UHI
I will take Mosher’s to this extent:
Steven Mosher says:
May 3, 2012 at 1:51 pm
The last study Zeke, nick stokes and I did, suggested a UHI trend from 1979-2010. That trend, about .04C per decade, is consistent with the handful of regional studies of UHI which all show trend bias of .03C to .125C per decade over the same period. It is REGIONALLY variable. One UHI does not fit all. In the SH, UHI is much smaller. In china and japan and Korean building practice drives it higher.
http://wattsupwiththat.com/2012/05/03/has-the-crutem4-data-been-fiddled-with/

AlexS

More silliness. Now 25 stations tells us the history of word temperatures!?

Richard Mallett

Reply to Alex S :-
I have specfically stated that I am not making any claims about the world outside Europe. I am making claims about Europe before 1850 and after 1850.

“..did not Mosher himself once say that 10 long station records would give approximately the same result as that from all records?”
Here’s an easy small size calculator:
http://www.measuringusability.com/ci-calc.php
It looks like what was taught in business statistics classes.
Enter 10 random numbers from 0.0 to 0.3 to represent temperature increases from 10 stations over 30 years. Then look for the confidence interval on the graph. It is possible that 10 stations are enough to draw a useful conclusion. I think it is argued that a sample size of 30 is pretty accurate. More than 30 doesn’t tighten the confidence interval much.
Interesting post. A skeptic and a warmist do a study of 30 randomly picked high quality stations.

Richard Mallett

Reply to Ragnaar :_
I don’t know who’s the sceptic and who’s the warmist, but the stations were not randomly selected. I plotted all 172 stations in CRUTem4 that had temperature records that started before or in 1850, then did conditional formatting in Excel to select those that had more than 200 years of coverage, 90% or greater coverage (Berlin had only 90% coverage) and had at least 70 years of coverage before 1850.

TheLastDemocrat

“Inevitably, the stations with the longest (and most complete) temperature records are all in Europe, so we cannot extrapolate to the rest of the world.”
Sure, we can. This is what the man-made global warming theory says. Overall, temps are rising. On a long-enough time scale, you will see this nearly everywhere or everywhere you have a long record, barring some contrary trend in occasional spots, such as the specific coastline where the Gulf Stream might lay its heat upon the British Isles across time.
Effects of the warming are supposedly evident in every corner of the globe. We are told that species habitats are moving all over the place. Species are going extinct all over the place. Drought, flood, tsunami, hail, and locust plagues are busting out all over.
The AGW cult members said it and they get to own it. Temps modestly representing any of the continents ought to show us this extreme effect. If a continent, or decent-size country, does not have significant, notable warming above and beyond natural variation, there ought to be a fairly obvious explanation for how it has ducked this global calamity.

Richard Mallett

Reply to The Last Democrat :-
Globally, from 1880-2014, GISS and NCDC have trended +0.65 per century, HadCRUT4 has trended +0.63 C per century. That looks pretty modest to me.

bw

Quality measurements must be samples that represent the surrounding “climate”, not air-conditioner exhaust. Show the “rural” temperatures. The “urban” temperature records must be rejected completely. Very few thermometers were ever placed with consistent scientific methodology.
That’s why the USCRN was created only recently.
http://hidethedecline.eu/pages/ruti/europe/western-europe-rural-temperature-trend.php
The global surface temperature record has never been measured with any scientific integrity.
Satellites do not measure surface temperatures.

darwin wyatt

Welcome to the end of the LIA… Expect glaciers to retreat even more and spruce forests to establish like during the MWP.

pochas

Wayne Delbeke says:
July 28, 2014 at 11:11 am
“it would seem less heat is being radiated out at night and when it is cold. Undoubtedly there are people here with ideas as to why the earth seems to be modulating temperature/heat in this way?”
An astute observation. It’s what you would expect from CO2. In daytime convection is working to maintain the lapse rate. At night convection stops and window radiation rules. “Window radiation” is radiation through that part of the IR spectrum that is transparent to radiation from the surface. The CO2 bands absorb on the edge of the window radiation hole, so with more CO2 the window gets smaller and surface temperatures must increase to get the same radiant flux through the narrower window and out to space. So we see nighttime warming, more in the continental interiors, and more at northern locations where there is little moisture in the air so that CO2 is relatively more important. In daylight hours convection largely negates the effect of CO2.

Ron C.

Greg Goodman
This study did not aim to critique the quality of the temperature data itself. We were interested in seeing the trends arising from CRUTEM4 data taken at face value. In the post, my comment means that we did no adjusting, anomalies or homogenizing to the data in our method of analysis.