Guest Essay By Werner Brozek, Edited by Just The Facts
In comparing GISS with the other five data sets that I comment on, some of the points I raise below overlap, and others could be added. However, and in no particular order, the following are some things that I have come up with on why GISS is unique. Perhaps you may disagree on some points or you may come up with others.
Image Credit JoNova
1. GISS uses two decimals whereas all others use three. While I agree that we do not know anomalies to the nearest 1/1000 or 1/100 of a degree, I find it very inconvenient. In my table, I give the 2013 anomaly rank, but with GISS, I need to check it every month since 2003 is usually tied to two decimal places, however they may switch places to three decimal places. Of course I realize that depending on how you look at it, there may be a ten way tie for sixth place, however if I want the best single number for the table, it is just a nuisance.
2. For 95% statistical significance, all others are above 17 years, but according to GISS, it is just over 14 years. See the table for details.
3. Including May, GISS has the most months in 2014 above the average of its record year of 2010, namely four of the five months. All other data sets have either zero or one or two months in 2014 above the anomaly average for its highest year. See the table for details.
4. GISS has the highest ranking after five months at first place. I realize it is only by 0.001 C and that could change when China’s numbers come in, but at the same time, 2010 could revert back to 0.65 from 0.66 next month. By contrast, RSS is eighth after five months. So while it is very probable that GISS will set a record, there is no way that RSS will do so. At this point, each of the last seven months on RSS would need to have an average anomaly of 0.775 and thereby smash every monthly record to date for every month from now to December. That is just not going to happen with RSS. The other rankings are from 4th to 8th.
5. GISS has the coolest period as the base period causing it to have the highest anomalies. However this does not affect the warming rate.
6. 1998 is ranked 4th which is the lowest of all data sets. Hadcrut4 has it as third and the others as first.
7. This is the warmest May ever recorded by GISS. However on RSS it is sixth; on UAH, version 5.5, it is fourth; on Hadsst3 it is second; and on Hadcrut3 it is also second. In all of these cases, at least the 1998 anomaly was higher. However Hadcrut4 also had May 2014 in first place by beating its 2010 mark by 0.004 C. However this difference is certainly not statistically significant.
8. GISS is the most quoted by warmists.
9. GISS is the most volatile of all data sets. Like James Bond, GISS has a reputation that precedes it. Why further it? Who will read a long and possibly a perfectly logical explanation when the end result is that a previous record is now easier to beat? For example, the 1998 anomaly of 0.62 in January was lowered to 0.61 now. Why can they not leave a 16 year old anomaly alone like the rest of the world?
10. And last, but not least, per JoNova, as shown referenced at the top of this article, GISS progressively realigns and reinterprets the temperatures from decades long ago:
In the parts below, as in the previous posts, we will present you with the latest facts. The information will be presented in three sections and an appendix.
The first section will show for how long there has been no warming on several data sets.
The second section will show for how long there has been no statistically significant warming on several data sets.
The third section will show how 2014 to date compares with 2013 and the warmest years and months on record so far.
The appendix will illustrate sections 1 and 2 in a different way. Graphs and a table will be used to illustrate the data.
Section 1
This analysis uses the latest month for which data is available on WoodForTrees.com (WFT). All of the data on WFT is also available at the specific sources as outlined below. We start with the present date and go to the furthest month in the past where the slope is a least slightly negative. So if the slope from September is 4 x 10^-4 but it is – 4 x 10^-4 from October, we give the time from October so no one can accuse us of being less than honest if we say the slope is flat from a certain month.
On all data sets below, the different times for a slope that is at least very slightly negative ranges from 9 years and 5 months to 17 years and 9 months.
1. For GISS, the slope is flat since September 2004 or 9 years, 9 months. (goes to May)
2. For Hadcrut3, the slope is flat since September 2000 or 13 years, 9 months. (goes to May)
3. For a combination of GISS, Hadcrut3, UAH and RSS, the slope is flat since January 2001 or 13 years, 5 months. (goes to May)
4. For Hadcrut4, the slope is flat since January 2001 or 13 years, 5 months. (goes to May)
5. For Hadsst3, the slope is flat since January 2001 or 13 years, 5 months. (goes to May)
6. For UAH, the slope is flat since January 2005 or 9 years, 5 months. (goes to May using version 5.5)
7. For RSS, the slope is flat since September 1996 or 17 years, 9 months (goes to May).
The next graph shows just the lines to illustrate the above. Think of it as a sideways bar graph where the lengths of the lines indicate the relative times where the slope is 0. In addition, the upward sloping blue line indicates that CO2 has steadily increased over this period:

When two things are plotted as I have done, the left only shows a temperature anomaly.
The actual numbers are meaningless since all slopes are essentially zero. As well, I have offset them so they are evenly spaced. No numbers are given for CO2. Some have asked that the log of the concentration of CO2 be plotted. However WFT does not give this option. The upward sloping CO2 line only shows that while CO2 has been going up over the last 17 years, the temperatures have been flat for varying periods on various data sets.
The next graph shows the above, but this time, the actual plotted points are shown along with the slope lines and the CO2 is omitted:

Section 2
For this analysis, data was retrieved from Nick Stokes’ Trendviewer available on his website Nick Stokes’ Trendviewer. This analysis indicates for how long there has not been statistically significant warming according to Nick’s criteria. Data go to their latest update for each set. In every case, note that the lower error bar is negative so a slope of 0 cannot be ruled out from the month indicated.
On several different data sets, there has been no statistically significant warming for between 14 and 21 years.
The details for several sets are below.
For UAH: Since February 1996: CI from -0.017 to 2.347
For RSS: Since November 1992: CI from -0.016 to 1.857
For Hadcrut4: Since October 1996: CI from -0.010 to 1.215
For Hadsst3: Since January 1993: CI from -0.016 to 1.813
For GISS: Since December 1999: CI from -0.004 to 1.413
Section 3
This section shows data about 2014 and other information in the form of a table. The table shows the six data sources along the top and other places so they should be visible at all times. The sources areUAH, RSS, Hadcrut4, Hadcrut3, Hadsst3, and GISS.
Down the column, are the following:
1. 13ra: This is the final ranking for 2013 on each data set.
2. 13a: Here I give the average anomaly for 2013.
3. year: This indicates the warmest year on record so far for that particular data set. Note that two of the data sets have 2010 as the warmest year and four have 1998 as the warmest year.
4. ano: This is the average of the monthly anomalies of the warmest year just above.
5.mon: This is the month where that particular data set showed the highest anomaly. The months are identified by the first three letters of the month and the last two numbers of the year.
6. ano: This is the anomaly of the month just above.
7. y/m: This is the longest period of time where the slope is not positive given in years/months. So 16/2 means that for 16 years and 2 months the slope is essentially 0.
8. sig: This the first month for which warming is not statistically significant according to Nick’s criteria. The first three letters of the month are followed by the last two numbers of the year.
9. Jan: This is the January 2014 anomaly for that particular data set.
10.Feb: This is the February 2014 anomaly for that particular data set, etc.
14.ave: This is the average anomaly of all months to date taken by adding all numbers and dividing by the number of months. However if the data set itself gives that average, I may use their number. Sometimes the number in the third decimal place differs slightly, presumably due to all months not having the same number of days.
15.rnk: This is the rank that each particular data set would have if the anomaly above were to remain that way for the rest of the year. It will not, but think of it as an update 25 minutes into a game. Due to different base periods, the rank is more meaningful than the average anomaly.
| Source | UAH | RSS | Had4 | Had3 | Sst3 | GISS |
|---|---|---|---|---|---|---|
| 1. 13ra | 7th | 10th | 8th | 6th | 6th | 7th |
| 2. 13a | 0.197 | 0.218 | 0.486 | 0.459 | 0.376 | 0.59 |
| 3. year | 1998 | 1998 | 2010 | 1998 | 1998 | 2010 |
| 4. ano | 0.419 | 0.55 | 0.547 | 0.548 | 0.416 | 0.66 |
| 5.mon | Apr98 | Apr98 | Jan07 | Feb98 | Jul98 | Jan07 |
| 6. ano | 0.662 | 0.857 | 0.829 | 0.756 | 0.526 | 0.93 |
| 7. y/m | 9/5 | 17/9 | 13/5 | 13/9 | 13/5 | 9/9 |
| 8. sig | Feb96 | Nov92 | Oct96 | Jan93 | Dec99 | |
| Source | UAH | RSS | Had4 | Had3 | Sst3 | GISS |
| 9.Jan | 0.236 | 0.262 | 0.509 | 0.472 | 0.342 | 0.67 |
| 10.Feb | 0.127 | 0.162 | 0.304 | 0.264 | 0.314 | 0.43 |
| 11.Mar | 0.137 | 0.214 | 0.540 | 0.491 | 0.347 | 0.71 |
| 12.Apr | 0.184 | 0.251 | 0.641 | 0.592 | 0.478 | 0.73 |
| 13.May | 0.277 | 0.286 | 0.586 | 0.539 | 0.479 | 0.76 |
| Source | UAH | RSS | Had4 | Had3 | Sst3 | GISS |
| 14.ave | 0.192 | 0.235 | 0.515 | 0.472 | 0.392 | 0.66 |
| 15.rnk | 8th | 8th | 4th | 5th | 5th | 1st |
If you wish to verify all of the latest anomalies, go to the following:
For UAH, version 5.5 was used since that is what WFT uses: http://vortex.nsstc.uah.edu/public/msu/t2lt/tltglhmam_5.5.txt
For RSS, see: ftp://ftp.ssmi.com/msu/monthly_time_series/rss_monthly_msu_amsu_channel_tlt_anomalies_land_and_ocean_v03_3.txt
For Hadcrut4, see: http://www.metoffice.gov.uk/hadobs/hadcrut4/data/current/time_series/HadCRUT.4.2.0.0.monthly_ns_avg.txt
For Hadcrut3, see: http://www.cru.uea.ac.uk/cru/data/temperature/HadCRUT3-gl.dat
For Hadsst3, see: http://www.cru.uea.ac.uk/cru/data/temperature/HadSST3-gl.dat
For GISS, see: http://data.giss.nasa.gov/gistemp/tabledata_v3/GLB.Ts+dSST.txt
To see all points since January 2013 in the form of a graph, see the WFT graph below.

As you can see, all lines have been offset so they all start at the same place in January 2013. This makes it easy to compare January 2013 with the latest anomaly.
Appendix
In this part, we are summarizing data for each set separately.
RSS
The slope is flat since September 1996 or 17 years, 9 months. (goes to May)
For RSS: There is no statistically significant warming since November 1992: CI from -0.016 to 1.857.
The RSS average anomaly so far for 2014 is 0.235. This would rank it as 8th place if it stayed this way. 1998 was the warmest at 0.55. The highest ever monthly anomaly was in April of 1998 when it reached 0.857. The anomaly in 2013 was 0.218 and it is ranked 10th.
UAH
The slope is flat since January 2005 or 9 years, 5 months. (goes to May using version 5.5 according to WFT)
For UAH: There is no statistically significant warming since February 1996: CI from -0.017 to 2.347. (This is using version 5.6 according to Nick’s program.)
The UAH average anomaly so far for 2014 is 0.192. This would rank it as 8th place if it stayed this way. 1998 was the warmest at 0.419. The highest ever monthly anomaly was in April of 1998 when it reached 0.662. The anomaly in 2013 was 0.197 and it is ranked 7th.
Hadcrut4
The slope is flat since January 2001 or 13 years, 5 months. (goes to May)
For Hadcrut4: There is no statistically significant warming since October 1996: CI from -0.010 to 1.215.
The Hadcrut4 average anomaly so far for 2014 is 0.515. This would rank it as 4th place if it stayed this way. 2010 was the warmest at 0.547. The highest ever monthly anomaly was in January of 2007 when it reached 0.829. The anomaly in 2013 was 0.486 and it is ranked 8th.
Hadcrut3
The slope is flat since September 2000 or 13 years, 9 months. (goes to May)
The Hadcrut3 average anomaly so far for 2014 is 0.472. This would rank it as 5th place if it stayed this way. 1998 was the warmest at 0.548. The highest ever monthly anomaly was in February of 1998 when it reached 0.756. One has to go back to the 1940s to find the previous time that a Hadcrut3 record was not beaten in 10 years or less. The anomaly in 2013 was 0.459 and it is ranked 6th.
Hadsst3
For Hadsst3, the slope is flat since January 2001 or 13 years and 5 months. (goes to May).
For Hadsst3: There is no statistically significant warming since January 1993: CI from -0.016 to 1.813.
The Hadsst3 average anomaly so far for 2014 is 0.392. This would rank it as 5th place if it stayed this way. 1998 was the warmest at 0.416. The highest ever monthly anomaly was in July of 1998 when it reached 0.526. The anomaly in 2013 was 0.376 and it is ranked 6th.
GISS
The slope is flat since September 2004 or 9 years, 9 months. (goes to May)
For GISS: There is no statistically significant warming since December 1999: CI from -0.004 to 1.413.
The GISS average anomaly so far for 2014 is 0.66. This would rank it as first place if it stayed this way. 2010 and 2005 were the warmest at 0.65 in April. But in May, 2010 was raised to 0.66, however to 3 digits, 2014 is very slightly warmer, although the difference is certainly not statistically significant. (By the way, 2010 was 0.67 in January.) The highest ever monthly anomaly was in January of 2007 when it reached 0.93. The anomaly in 2013 was 0.59 and it is ranked 7th.
Conclusion
GISS is unique in many ways. Can you think of other ways in which GISS is unique that I have missed? I seem to have the impression that most adjustments serve one of two purposes. With the odd exception, they either make the present warmer and the past cooler. However if this is not the case, then the adjustments make a new record easier to happen. Is this a fair assessment?
P.S. RSS came so fast for June and Hadcrut3 was so slow for May that the June value for RSS came in before I completed the report. As a result of the June value for RSS of 0.345, the average for RSS for the first six months is 0.253. If it stayed this way, it would rank 7th. However the time period for a slope of zero increased from 17 years and 9 months to 17 years and 10 months.
UAH, version 5.6 has also came out, although nothing shows on WFT yet. It was interesting, but not unexpected for me that UAH went down from 0.327 to 0.303. However RSS went up from 0.286 to 0.345.
Please correct me if I am wrong about the reason. It is my understanding that RSS only goes to 70 degrees south, whereas UAH goes to 85 degrees south.
According to this, it has been is cold in the Antarctic lately. Perhaps this cold anomaly has been captured by UAH but not by RSS. Does this make sense?

This one post says it all….
http://stevengoddard.wordpress.com/2014/07/03/giss-data-tampering-worse-than-it-seems/
A man with six? seven? eight? watches doesn’t know what time it is – or was.
Thanks, guys
How does an outfit like GISS end up changing historicl data so many times ? Do they make some apparently justifiable changes to the data, but fail to record that they made those changes, then several years later, someone thinks that the data hasn’t had the adjustments made and sets the computer going again, and a few years later he leaves, a new person joins and eager to make the right impression finds that the necessary adjustments haven’t been made and makes thos adjustments yet again.
The last on shown was 2007, perhaps another set of adjustments will be made this year if indeed they haven’t already been made
What possible justification is there for perpetual adjustments ?
J Martin says:
July 5, 2014 at 9:16 am
“What possible justification is there for perpetual adjustments ?”
To fix errors made by previous adjustments.
GISS is the most alarmist biased of reporting sitesand all attempts to make it the alpha source for global temperature will be made by the team. Even though it only covers a small proportion of the land mass, and none of the sea surface ,it is most quoted. Ironic that their figures show cooling trends over much of the country according to their “climate at a glance” page on a decadal trending.
What possible justification is there for perpetual adjustments
============
start here…..
http://wattsupwiththat.com/2014/06/26/on-denying-hockey-sticks-ushcn-data-and-all-that-part-2/#comment-1670422
Historical data for sea level is being rewritten as well:
http://oi59.tinypic.com/24e8482.jpg
Calculate from the anomaly data the real global temperature and compare then the different data sets. I guess that you will find that they differ more than 0.1 °C. (The weather stations always measure temperatures not anomalies.) That’ s a simple method to find the error of measurement. I guess most of your statements will disappear in the sea of error.
When I looked at GISS in 2007, they used a weird “two-legged” adjustment to individual stations that is not used by anyone else. I haven’t checked their recent methods to determine whether it’s still being used, but it probably is. See http://climateaudit.org/2008/06/23/nasa-step-2-some-benchmarks/; http://climateaudit.org/2008/06/22/nasa-step-2-another-iteration/
If it is still being used, it will introduce a variety of bizarre and pointless artifacts. Because these methods have been used by GISS for a long time, I don’t think that people should presume that there’s necessarily a reason for the various artifacts – though if GISS’ stupid methods had gone the other way, one would surmise that they would have re-examined them long ago.
I would recommend that people interested in GISS spend some time with the CA posts on the topic, as my brief perusal of recent commentary on the topic indicates to me that people have not bothered familiarizing themselves with previous work on the topic.
GISS is the worst of all of the surface series. And I’m not saying that the others are correct.
Nice job once again WB and JTF!
There went my lunch hour pondering GISS smoothing, homogenization, and extrapolation involved 🙂
Only thing GISS manage to prove is lack in usage of Theories of Science choosing Fallacies and “corrections”….. mind you trying to hunt one’s own tail doesn’t come cheap….
Good information. But if you’re going to discuss a temperature series like GISS, why assume that we have all these acronyms memorized and know exactly what it is? Why not give a brief review? Reminding us that GISS is the global surface temperature series maintained by NASA would probably be enough to jog memories for some of us who are not immersed in this stuff on a daily basis. It always made sense to me to define an acronym the first time it is used in an article. Forcing thousands of readers to Google a term just to save the author a few seconds of time never made any sense to me.
Steve McIntyre says: July 5, 2014 at 9:53 am
“I haven’t checked their recent methods to determine whether it’s still being used, but it probably is.”
My understanding is that they now use GHCN V3 adjusted as a starting point. This incorporates Menne’s pairwise algorithm, which thus replaces their old scheme. So I don’t think it is still being used.
Steve McIntyre says:
July 5, 2014 at 9:53 am
Thank you for that! The question that I now have is whether or not what GISS is doing is even proper, assuming they are doing it without any bias. For example, is HadCRUT4 now somehow inferior to GISS for not doing what GISS is doing? Or is GISS inferior to HadCRUT4? Or are they just different without a possibility of value judgement?
“10. And last, but not least, per JoNova, as shown referenced at the top of this article, GISS progressively realigns and reinterprets the temperatures from decades long ago:”
This just indicates another undoubted uniqueness – GISS has been around a lot longer than any other index. They may have changed since the 80’s; no-one else was estimating at all then. And a 1980 estimate would have been based on thin data. Only a fairly small fraction had been digitised.
“1. For GISS, the slope is flat since September 2004 or 9 years, 9 months. (goes to May)”
On my calc it was below zero from Nov 2001 to April 2014. It’s possible May put it over the line, but these are very fine and basically random distinctions.
Louis says:
July 5, 2014 at 10:44 am
Sorry about that! However in my defense, I would like to note that Walter Dnes just had an article two days ago called: GISS Hockey-Stick Adjustments
So it is not as if it has been a long time since the acronym was last used here in a title.
However I will try to remember next time!
What is GISS?…..it is not explained…it baffles me…
Vern Cornell says:
July 5, 2014 at 11:20 am
What is GISS?…..it is not explained…it baffles me…
>>>>>>>>>>>>>>>
There are 4 main temperature records of the earth. Two land records and two satellite records. The two land records are:
NASA GISS
University of East Anglia HadCrut
The two satellite records are:
NASA RSS
University of Alabama Huntsvile UAH
I shouldn’t have picked on you, Werner. GISS is one of the more common acronyms. But there have been past articles that have frustrated me because they throw out obscure acronyms left and right without defining any of them. Even with the ones I am somewhat familiar, I have a hard time remembering which ones are satellite data, surface temperature data, or ocean temperature data. I think age has something to do with it, but there may be others in my same boat.
Vern Cornell says:
July 5, 2014 at 11:20 am
What is GISS?…..it is not explained…it baffles me…
===========================================
I thought that is what Google is for, to debaffle people.
To most of us who are skeptical of CAGW, the consistency of the GISS temp adjustments comes as no surprise. Putting Hansen or Schmidt in charge of temperatures gives them a unique opportunity to perpetuate the world’s greatest science hoax.
I am eagerly waiting the day NASA or NOAA whistleblowers expose the fraud being foisted on the world’s scientific community. The adherence to the scientific method has been violated and a large portion of the public are aware of the corruption. Following the end of the manmade climate change era, it will be a long time until the scientific community regains public trust and an even longer time (if ever) for politicians, who jumped on the CAGW bandwagon in its hay day.
I think GISS = Goddard Institute for Space Studies.
werner, thanks for a great, comprehensive, clear and concise update and comparison of the different GSTA data-sets. GSS is clearly in a world of its own… unfortunately…
One of the main problems with all these adjustments is that if one tries to change the past, one is doomed to make the same mistakes again in the future (since one isn’t learning from the past). Hence, policies to affect the future that are based on data that changes the past will fail and be likely counter productive. This actually warrants a whole essay by itself.