UPDATE: 08/07 2:PM PST MLO responds with improvements to the CO2 data reporting
Approximately 24 hours after I published my story on the January to July trend reversal of CO2 at Mauna Loa, the monthly mean graph that is displayed on the NOAA web page for Mauna Loa Observatory has changed. I’ve setup a blink comparator to show what has occurred:
For those who don’t know, a blink comparator is an animated GIF image with a 1 second delay consisting only of the two original images from NOAA MLO. Individual image URLS for: August 3rd ML CO2 graph | August 4th CO2 Graph
Now the there is no longer the dip I saw yesterday. Oddly the MLO CO2 dataset available by FTP still shows the timestamp from yesterday: File Creation: Sun Aug 3 02:55:42 2008, and the July monthly mean value is unchanged in it to reflect the change on the graph.
[UPDATE: a few minutes after I posted this entry, the data changed at the FTP site] here is the new data for 2008:
# decimal mean interpolated trend
# date (season corr)
2008 1 2008.042 385.37 385.37 385.18
2008 2 2008.125 385.69 385.69 384.77
2008 3 2008.208 385.94 385.94 384.50
2008 4 2008.292 387.21 387.21 384.46
2008 5 2008.375 388.47 388.47 385.46
2008 6 2008.458 387.87 387.87 385.51
2008 7 2008.542 385.60 385.60 385.25
and here is the 2008 data from Sunday, August 3rd:
2008 1 2008.042 385.35 385.35 385.11
2008 2 2008.125 385.70 385.70 384.85
2008 3 2008.208 385.92 385.92 384.38
2008 4 2008.292 387.21 387.21 384.59
2008 5 2008.375 388.48 388.48 385.33
2008 6 2008.458 387.99 387.99 385.76
2008 7 2008.542 384.93 384.93 384.54
Here is the MLO data file I saved yesterday (text converted to PDF) from their FTP site.
Here is the URL for the current data FTP:
ftp://ftp.cmdl.noaa.gov/ccg/co2/trends/co2_mm_mlo.txt
I have put in a query to Pieter Tans, the contact listed in the data file, asking for an explanation and change log if one exists.
UPDATE 08/05 8:55AM PST I have received a response from MLO:
Anthony,
We appreciate your interest in the CO2 data. The reason was simply that
we had a problem with the equipment for the first half of July, with the
result that the earlier monthly average consisted of only the last 10
days. Since CO2 always goes down fast during July the monthly average
came out low. I have now changed the program to take this effect into
account, and adjusting back to the middle of the month using the
multi-year average seasonal cycle. This change also affected the entire
record because there are missing days here and there. The other
adjustments were minor, typically less than 0.1 ppm.
Best regards,
Pieter Tans
UPDATE 08/05 4:03PM PST
I have been in dialog with Dr. Tans at MLO through the day and I’m now satisfied as to what has occurred and why. Look for a follow-up post on the subject. – Anthony
UPDATE 08/06 3:00PM PST
A post-mortem of the Mauna Loa issue has been posted here:
http://wattsupwiththat.wordpress.com/2008/08/06/post-mortem-on-the-mauna-loa-co2-data-eruption/
– Anthony
So, why does ALL the data change?
Have they suddenly discovered the Hansen method of adjustment?
[…] Watts Up With That? has the story. […]
For those who are not familiar with the Data Quality Act (DQA), here is a well written overview.
http://library.findlaw.com/2003/Jan/14/132464.html
While we (the world) deserve a clear explanation/understanding of what these adjustments are and why they were made, this is one dataset where the adjustments don’t yet bother me too much as long as the past trend line does not alter appreciably as a result. The reason it doesn’t bother me is that if we are, indeed, beginning to see a downtrend in the CO2 level measured as Mauna Loa, then they won’t be able to mask it for very long, since CO2, unlike temperature has been claimed to be monotonically increasing. Any sustained downtrend over the next year or so would break that cycle and change the whole ballgame. On the other hand, if the overall trend resumes an upward direction, then the downtick would have appeared to be an outlier and wouldn’t have survived as the biggest nail in the coffin of the AGW hysteria. So, as usual, we’ll have to wait and see. In the meantime, I look forward to reading whatever you hear back for an explanation.
These folks should should invest in a software engineering technique called “version control”,
considering how soft and malleable all this historical data appears to be.
An answer might come out of this:
http://www.esrl.noaa.gov/gmd/co2conference/pdfs/changingcarbon.pdf
Note the summary. It seems the winds are strong enough to blow the words away 😉
Darn, and I thought less driving had stopped global warming. Oh well, Pelosi needs to stick to her no more drilling and get gas up to $5 a gallon. I wonder if she can somehow stop the mining of coal?
Looking forward to the log which will explain changes in Mauna Loa monthly means back to May 1974. I wonder if there is a separate explanation for each month’s adjustment. Also, how many historic data points HAVE been adjusted?
Thanks,
Mike Bryant
malcolm (02:04:28) & jeez (02:11:06)
The point about NSIDC is well taken; there had been several days of a pronounced uptick (showing a slower melt rate) on the melt line up through 31 July. When the line was revised 1 Aug the direction it took suddenly changed to show a quickening melt rate and the change was pushed back by several days.
Perception is reality — if it appears that data is being continually adjusted, it may lead to the perception that science is unreliable and that the data upon which policy decisions are to be based is flawed. It is not a huge leap for the perception to grow of scientists having their own agenda and cooking the books to realize that goal.
For the Mauna Loa data to be up for possible adjustment for a year seems rather reasonable. But now, when decades of data are tweaked, a questioning perception may take hold. I patiently await a reponse to Anthony’s query about the changes.
Anthony,
I know this is off topic and may have already been posted in another area (I have a hard time keeping up with all the comments some days). If you don’t want this one posted go ahead and delete, but I thought it was interesting, maybe some truth will come about from it. Seems alaska is sueing Feds about the decision to make Polar Bears endagered.
http://hosted.ap.org/dynamic/stories/P/POLAR_BEAR_LAWSUIT?SITE=VANOV&SECTION=HOME&TEMPLATE=DEFAULT
aaah this is the real world BOM do it here all the time – cold day – ooops the temperature just jumped 2 degrees at observatory hill (all the while temps in the rest of sydney were going down) – and then back again – quite funny really when you get to the point that you cant trust those who record the weather – i just look at the guage in my car now – and its almost offensive now to talk about the cold – warming is the new black ROFL
Combine this with a blinking graph on the hockey stick too! You may go down in history with Charles Johnson of LGF with the ‘throbbing memo’ of Dan Rather fame…er, infamy. Good catch! Keep em honest out there.
Well spotted Anthony, good to see you are keeping them on their toes!
I’ve always been a “show me the data” kind of guy when it comes to this global warming caused by man hype. It’s why I love this site. What really concerns me is that the government is massaging the data to support some obscure agenda.
That’s huge if you think about it. I’m anxious to hear their response.
Looks like a pretty typical change to a smoothing algorithm. Didn’t know they used one but maybe they take multiple data points each day and filter them.
If that’s what they did, then a good question would be “why now?”.
Small adjustments go back at least to the 70’s.
Is this really good or bad ?
I mean, I can see some who will claim that this is why there has been a drop in global temperatures (i.e. tail wagging the dog).
If any think that this is grasping at straws, just remember that this is a bellwether site for the AGW hypothesis. So it deserves all the scrutiny it gets, and has to live up to the strictest standards because of it.
Anthony,
As much rancor exists between you and Tamino, that comment by Mike C above might be a bit beyond the bounds of civility that you usually accept at this site.
As far as CO2 trends goes, it seems like Lucia was spot on about the calibration error.
REPLY: Edited, thanks for pointing it out. I’m waiting for explanation from MLO, and while I can see calibration error in this past month as reasonable, the changes back down the entire dataset to 2004 don’t seem reasonable for calibration error.
There is also a suspicious graph change at NSIDC: http://www.nsidc.com/arcticseaicenews/
It seems some of last months data has been adjusted downward. Also there is a very suspicious almot linear drop up to the 4th August from about 28th July. A blink comparison with the same graph further down the page (although that graph is only up to 1st August). This would show a definite data adjustment for late July.
One explanation for all these changes is that they are using an error correction algorithm that uses previous trends to determine if there might be an error. The more the data varies from the previous annual/seasonal trend, the more the raw data will be adjusted.
Each year in the newest post-adjustment graph looks more similar to other years after the changes.
If that is what they doing, then we will never have any kind of variation in the “march of the CO2”. I imagine they have been doing this all along whenever a strange data point emerges.
The more you look at the historical datasets in the climate science field, the more “rewriting of history” you will find and the less faith you will have in any of data.
I am not a conspiracy theory supporter. Hopefully, the changes documented above will be shown to be necessary and done for good reason.
However (although this is a little off-thread), lest anyone think that science will easily carry the day in overturning the AGW meme, I offer this piece from the Boston Globe by Dr. John P. Holdren of Harvard and Woods Hole. It is a reality check that AGW won’t go quietly into the dark night.
http://www.boston.com/bostonglobe/editorial_opinion/oped/articles/2008/08/04/convincing_the_climate_change_skeptics/
Excerpts:
“THE FEW climate-change “skeptics” with any sort of scientific credentials continue to receive attention in the media out of all proportion to their numbers, their qualifications, or the merit of their arguments. And this muddying of the waters of public discourse is being magnified by the parroting of these arguments by a larger population of amateur skeptics with no scientific credentials at all…”
Dr. Holden concludes:
“The extent of unfounded skepticism about the disruption of global climate by human-produced greenhouse gases is not just regrettable, it is dangerous…Those who still think this is all a mistake or a hoax need to think again.”
Arguably, data are the readings taken from the instruments, which should be presumed to be properly calibrated. Once data points are “massaged”, they are no longer data points, but rather a collection of numbers which represent what the data points would/should have been had the data points been collected properly from properly calibrated instruments; and, to my mind at least, the numbers in the number places which have been changed by the “massaging” are no longer significant.
I understand that, in the case of climate, it is not possible to go back to the lab, recalibrate the instruments and rerun the experiment. However, that is a compelling reason to assure that the instruments are sited and calibrated properly, not a reason to “massage” the date to assure that it is “on message”.
Unknown and unsubstantiated data adjustments are the way of the future.
Once government started on the “pay more in taxes so government could pretend to control the weather” path, we were cooked. Government as an honest broker no more, the day increasing taxes and controlling behavior becomes the goal of science. Want proof, all you have to do is read the NASA site, AGW tripe and BS they pass off as PROVEN FACT is just eye popping.
Regarding the changed chart at the NSIDC, there was actually two different charts shown on the page announcing the end of July sea ice extent. One going up and one going down.
http://nsidc.org/arcticseaicenews/index.html
I believe the downturn in the chart just reflects newer data (although the one going up is labeled August 1, 2008 and the release came out on this day.)
You can open both these charts in separate windows and by clicking back and forth, get a before and after animation like Anthony did for the CO2 data. The downturn is a longer line.
http://nsidc.org/images/arcticseaicenews/20080801_Figure2.png
http://nsidc.org/data/seaice_index/images/daily_images/N_timeseries.png