GISStimating 1998

By Steve Goddard

h/t to reader “Phil.” who lead me to this discovery.

In a previous article, I discussed how UAH, RSS and HadCrut show 1998 to be the hottest year, while GISS shows 2010 and 2005 to be hotter.

But it wasn’t always like that. GISS used to show 1998 as  0.64 anomaly, which is higher than their current 2005 record of 0.61.

You can see this in Hansen’s graph below, which is dated August 25, 1999

But something “interesting” has happened to 1998 since then. It was given a demotion by GISS from 0.64 to 0.57.

http://data.giss.nasa.gov/gistemp/graphs/Fig.A2.lrg.gif

The video below shows the changes.

Note that not only was 1998 demoted, but also many other years since 1975 – the start of Tamino’s “modern warming period.” By demoting 1998, they are now able to show a continuous warming trend from 1975 to the present – which RSS, UAH and Had Crut do not show.

Now, here is the real kicker. The graph below appends the post 2000 portion of the current GISS graph to the August 25, 1999 GISS graph. Warming ended in 1998, just as UAH, RSS and Had Crut show.

The image below superimposes Had Crut on the image above. Note that without the post-1999 gymnastics, GISS and Had Crut match quite closely, with warming ending in 1998.

Conclusion : GISS recently modified their pre-2000 historical data, and is now inconsistent with other temperature sets. GISS data now shows a steady warming from 1975-2010, which other data sets do not show. Had GISS not modified their historic data, they would still be consistent with other data sets and would not show warming post-1998. I’ll leave it to the readers to interpret further.

————————————————————————————————————-

BTW – I know that you can download some of the GISS code and data, and somebody checked it out and said that they couldn’t find any problems with it. No need to post that again.

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Ive learned much since becoming a frequent reader of WUWT. One of the things Ive learned is proponents of AGW are charlatans.

Günther Kirschbaum

This all extremely interesting (especially the note at the end saying how we don’t need to hear that nobody who knows how to work with the GISS code and data can strengthen your implied accusation of fraud), but I think most people are more interested in the next fair, comprehensive and balanced Sea Ice News.

Layne Blanchard

The falsifications being made to the record are made before they’re posted. Looking back even further in time, there are versions of this graph that correctly place the 1930s as the warmest era.

Wilky

Revisionist history is alive and well at NASA I see…

The Ghost Of Big Jim Cooley

But this isn’t surprising, as GISS use proxy data for the Arctic – where there are no recordings. So Hadley are correct in their assertion (to me, by email, from Phil Jones – yes, really) that their’s is the one to choose. If there are no recordings, you can’t simply ‘assume’ by using a proxy that is a massive distance away, and may itself, be subject to surrounding influences. GISS assert that you can, but that’s ‘science’ now!

Sean

I wonder if hanson took a data plotting seminar from the financial folks at GE?

harrywr2

I’ll offer a hypothesis.
A UHI adjustment lowers the historical temperature of a place.
Apparently it’s just a flag that goes with the station location. In reality it needs to have a date associated with it. I.E. Before 1950 it’s rural, after 1950 it’s urban or something like that.

savethesharks

And I always thought Fiddle Faddle was some sort of candy popcorn.
Now we know Hansen and Mann and company actually codified a truer definition to the phrase…
Chris
Norfolk, VA, USA

Tenuc

Wow here we go again!
GISS 1998tempgate anyone???

Daniel H

Could this discrepancy be related to Hansen’s post Y2K adjustment error? That was discussed here:
http://wattsupwiththat.com/2007/08/11/does-hansens-error-matter-guest-post-by-steve-mcintyre/

rc

Regarding the code of course changes (and their effects) can be valid but the fact that you can only check out the GISS code now says a lot. They don’t seem to have had their code in anything resembling a reasonably modern Change Management system.
For GISS to have credibility all code and data for each of the “versions” of their temperature records should be formally documented and a few clicks away.

Daniel H says:
August 29, 2010 at 8:45 am
Could this discrepancy be related to Hansen’s post Y2K adjustment error? That was discussed here:
http://wattsupwiththat.com/2007/08/11/does-hansens-error-matter-guest-post-by-steve-mcintyre/

As I explained when I first posted about this that’s exactly why the adjustment was made but that appears to have been left out in this post.

Phil.
It is one of the miracles of modern science how GISS corrections almost invariably seem to make the past cooler, and the present warmer.
Sooner or later they may be able to correct away the Dust Bowl entirely.

M White

“Uncertain Climate – In a special Radio 4 series the BBC’s Environmental Analyst Roger Harrabin questions whether his own reporting – and that of others – has adequately told the whole story about global warming”
http://www.bbc.co.uk/programmes/b00tj525
“He finds that the public under-estimate the degree of consensus among scientists that humans have already contributed towards the heating of the climate , and will almost certainly heat the climate more.”
The first programme is on tomorrow morning at 09:00 BST. It looks lim AGM is not to be questioned but the alarmism may be.
Steve McIntyre has a say in this program. I wonder if they’ll mention GISS and James Hansen.

ZT

Welcome to the temple of conceptual climatology. The projections are robust, as the continually evolving historical records clearly demonstrate.

James H

These adjustments of the past are always happening. A couple of years ago, one of these blogs (maybe it was The Blackboard), noticed how temperatures back to the early 20th century were being adjusted down by small amounts. I think that in another 100 years, it will look like the ice age didn’t end 14000 years ago or whenever we think it did now. If you were to ask what the temperature was in 1930, you would also have to state what year you want it referenced from – the number you get this month is different than last month or last year.

Fred

When people look back on this era, they will shake their heads in disbelief and disgust at how corrupt, inept and down right crooked science became.
Climate Scientology . . . the Alchemy of our generation.

Leon Brozyna

Creativity is alive and flourishing at GISS:
Creative science
Creative thinking
Creative writing
Creative graphing
Creative statistics
Creative data tweaking …

Mikael Pihlström

Anthony Watts says:
August 29, 2010 at 9:44 am
Personally I have no trust in GISS whatsoever. Hansen has blown his agency credibility with his conversion to “activist” by his own admission:
http://www.columbia.edu/~jeh1/mailings/2010/20100824_Activist.pdf
I really can’t trust a scientist who combines global data gatekeeper role with a jailbird role.
——————-
In twenty years time I think the world will thank “the jailbird” and
curse the Heartland and other disinformation teams.
REPLY: With people like William Connolley helping such efforts at Wikipedia, perhaps, but what will Nature say? And I’m not talking about the publication. – Anthony

Tamino says—“the modern global warming era starts in 1975.” With or without the 1998 adjustment there has been warming since 1975. And it can be called ‘modern’ since it is. And it is ‘global’ if you talking about the mean temperature. So he’s right, it’s modern global warming. I wouldn’t use the word ‘era’ though because that’s an exaggeration.
But I know why he puts that in: he wants the reader to infer its the “manmde” global warming ‘era’.
All kinds of implied meanings going on in ‘global warming’, i.e., sophistry.

Tom in Co

Stephen Schneider, a lead in the 2007 UN IPCC report, had said the following in 1989:
“To capture the public imagination, we have to offer up some scary scenarios, make simplified dramatic statements and little mention of any doubts one might have. EACH OF US HAS TO DECIDE THE RIGHT BALANCE BETWEEN BEING EFFECTIVE, AND BEING HONEST” (emphasis mine)
I guess the GISS just wanted to be more “effective” in this case

Refresh my memory. Didn’t four of the world’s most distinguished meteorological organizations record a worldwide temperature drop of 0.595C in 1998?
Hansen’s graph only shows about a 0.24C drop. Is this the homogenized version of 0.595C? This might explain the fifth sentence “But something interesting has happended to 1998 since then”. Looks to me like Dr. James “thumb on the temperature scale” Hansen is back at work again doing what he does best – cooking the books!

David Davidovics

I’m glad some one else noticed this. I was involved in a few climate debates on different forums a couple years ago and used NASA graphs to make my point of mild cooling post 1998. Later when I looked back on those conversations, I found the links were dead and those graphs were no where to be found. This was the first time I realized that revisionist practices were in play at NASA. Since then I try to save such pieces of information to hard drive just in case.

John Goetz

They are not really adjustments. They are an artifact of the way GISStemp estimates missing monthly and seasonal temperatures. I wrote about it on WUWT a little over two years ago here:
http://wattsupwiththat.com/2008/04/08/rewriting-history-time-and-time-again/
(Looking at the old article it looks like the format of the formula got a little hosed.)
If I am missing the temperature for March, 1990 in East Podunk, Maine, GISStemp will use all the historical March, April, and May temperatures for that station in an effort to GISS-timate that missing monthly temperature. Because GISStemp is run start to finish every month with the most recent monthly data added to the pot, that previous estimated temperature can change due to the addition of recent data.
The GISStimation might not be that big a deal if there were only a few data points missing, but the problem is there are lots of data points missing. As a result we notice the results of GISStemp changing over and over.

An iota of 0.07 shaved off and voilà, you’ve got dangerous global warming.

0.07 changed in GISTemp wouldn’t change the GISTemp trend on a decades scale. So to say the trend between CRU and GISS is still the same doesn’t apply to what this post is about.
Just saying that preemptively. In case a maelstrom breaks out later I won’t have to come out of my foxhole. 😉

They are either so incredibly stupid that they assume no one has been checking on them, or they are so blindly hubristic that they believe it doesn’t matter that people have been doing so.
In either case, this shreds any remaining credibility GISS may have had.

Peter Miller

This is a good summary of the subject, and a damning exposure of GISS’ manipulations of historical data, written last year with several references to WUWT and Climate audit.
http://www.google.co.uk/url?sa=t&source=web&cd=4&ved=0CCgQFjAD&url=http%3A%2F%2Ficecap.us%2Fimages%2Fuploads%2FUS_AND_GLOBAL_TEMP_ISSUES.pdf&ei=-ph6TJbvHOPQ4wbSrr2pBg&usg=AFQjCNFxIm9_DDZqugbnN-vrtDB6YhZlKA

Here is an examination of Hansen’s continual adjustment of the data:
http://www.appinsys.com/GlobalWarming/Hansen_GlobalTemp.htm

Amino Acids in Meteorites says:
August 29, 2010 at 10:13 am
0.07 changed in GISTemp wouldn’t change the GISTemp trend on a decades scale. So to say the trend between CRU and GISS is still the same doesn’t apply to what this post is about.
AAIM: When you adjust 1998 it allows you easier to claim that temperatures are still rising even in the last decade.
K.R. Frank

rbateman

An Anomaly can be misleading (shhh…. don’t tell anyone…it’s a big secret) when that is all one is shown.
But, under the hood, when the absolute temp is added back, the anomaly doesn’t look so big, bad & intimidating:
http://www.robertb.darkhorizons.org/TempGr/HADcrut3gl.JPG
So I got the HADcrut3gl data from Wood for Trees.
What I did :
Copied the HADcurt3gl anomaly data (1850 to 2010) to 2 columns to plot.
To the first column I added 12.5 C to the anomaly to get the absolute temp back.
(hey, I tried to find the absolute temp, but nobody thinks of posting that any more….WUWT??)
Next, I multiplied the 2nd column by 10 to restore the Boogie Man OMG we’re all going to boil & drown effect, and plotted it all.
So, whoop, there it is. Doesn’t look so big & ugly anymore.

kadaka (KD Knoebel)

No need to talk about the code, nor to rework a person’s words to ascribe non-existent dark reasons for not talking about the code.
We’re just looking at the outputted results and how they were adjusted over time into saying something different, now different from other major temperature datasets. No need to go into how good truly-raw temperature records were ingested, homogenized, and excreted as those results.

savethesharks

rbateman says:
August 29, 2010 at 11:05 am
An Anomaly can be misleading (shhh…. don’t tell anyone…it’s a big secret) when that is all one is shown.
But, under the hood, when the absolute temp is added back, the anomaly doesn’t look so big, bad & intimidating:
===============================
Thank you for that graph!
Chris

savethesharks

More like “GIZZstimating, 1998”, Steve.
Chris
Norfolk, VA, USA

David S

Hansen needs to explain these changes to history… preferably on the witness stand under penaly of perjury.

GeneDoc

Who controls the past controls the future. Who controls the present controls the past.
— George Orwell

Gary Pearse

A composite video of the alterations to the temp graph by GISS over the past decade would look line a worm wiggling on dry pavement before death ensues.

Looks like GISS had an anomoly with their anomolies!

pochas

To compensate for UHI effect, GISS does not adjust current urban temperatures downward to remove the effect of UHI, but instead it adjusts all historic temperatures downward, thus emphasizing the effect! This invalidates everything they say.

ImranCan

Its just another example of knowing what the answer s in advance (in this case steadily rising temperatures) and then adjusting the data to fit the required result. We shouldn’t be surprised because it isn’t science, its religion.

DocMartyn

As I have said before; I have know idea what will happen to future temperatures, but I am sure that past temperatures will get colder.

TomRude

Gavin “predicted” 2010 would be the warmest on record. Gavin is g(e)o(i)d. Well he figured if it goes in El Nino mode and with GISS adjustments… There is no better race to call than the one you already know the result of…

rbateman

savethesharks says:
August 29, 2010 at 11:21 am
Thank you for that graph!
Chris

My pleasure.
Now, if we add the GISS adjustment, GISS anomaly and raw data set up, I dare say we could turn the equivalent of gold into lead.
“It’s lead, Jim. I’m a doctor, not an alchemist.”

MinB

Maybe this is simpleminded, but has anyone asked directly what were the changes, when were they made, and why?

GISS should be called the Great Institute for Stupid Scientists.

Anu

Oh good – no warming since 1998. Surely the Arctic sea ice will continue it’s 2008 and 2009 summer minimum recovery from the bad-weather summer of 2007, just as the citizen/amateur climatologist/skeptics confidently predicted.
…what will Nature say? And I’m not talking about the publication. – Anthony
Exactly.
You can’t accuse Nature of being incompetent, a charlatan, staging a hoax, revising history, or having been arrested.

Rhoda R

GISS and other activist organizations don’t need to worry about their long term credibility, they only need it long enough to get the global control and one world government in place. Once that is done no one will dare question them.

Frank Lansner says:
August 29, 2010 at 10:58 am
AAIM: When you adjust 1998 it allows you easier to claim that temperatures are still rising even in the last decade.
K.R. Frank

I know.
What I was doing was trying to head off an argument from a couple of weeks ago. In a previous posts about James Hansen/GISS by Steven Goddard there was an argument made by a commenter that Steven Goddard was treating James Hansen unfairly (thus making WUWT look bad) by pointing out the differences between GISTemp and other sets sets over the last 12 years, i.e., 1998 to 2010. The commenter said that was too short a time period and that over the long term the trend between CRU and GISS has been the same. The shaving of the data by things like 0.07 here and there wont show up in the long term trend. They get blended in. But, as you point out, it changes the data set in the short term into continued global warming.
Here’s the CRU and GISS 1900 – 1998 trend
http://www.woodfortrees.org/plot/hadcrut3vgl/from:1900/to:1998/trend/plot/gistemp/from:1900/to:1998/trend
Here’s the CRU and GISS 1900 – 2010 trend
http://www.woodfortrees.org/plot/hadcrut3vgl/from:1900/to:2010/trend/plot/gistemp/from:1900/to:2010/trend
Here’s the CRU and GISS 1998 – 2010 trend
http://www.woodfortrees.org/plot/hadcrut3vgl/from:1998/to:2010/trend/plot/gistemp/from:1998/to:2010/trend
And last, CRU, GISS, RSS, and UAH 1998 – 2010
http://www.woodfortrees.org/plot/hadcrut3vgl/from:1998/to:2010/trend/plot/gistemp/from:1998/to:2010/trend/plot/rss/from:1998/to:2010/trend/plot/uah/from:1998/to:2010/trend

pochas

ImranCan says:
August 29, 2010 at 12:16 pm
“Its just another example of knowing what the answer s in advance (in this case steadily rising temperatures) and then adjusting the data to fit the required result. We shouldn’t be surprised because it isn’t science, its religion.”
If the Church adjusted data as fast as GISS, they would have zero believers.