One day later: Mauna Loa CO2 graph changes

Joy,
On my explanation page I have the two graphs of raw data for 2004: with and without outliers. Most outliers were to the low side (due to upslope winds, some 4 ppmv below average). That was a year with few days with volcanic outgassing. 1984 e.g. was a year with many days of high outliers due to volcanic outgassing (peaks of +20 ppmv). Both outliers are not used for daily, monthly and yearly averages, but still are available in the raw hourly averages data file.
I suppose that they simply have an automatic update of the monthly data, with as only algorithm that there must be at least 10 days of valid data. What they probably never had encountered is that if these 10 days were all at the end (or the beginning) of a month, this might give a bias in months with a huge seasonal trend…

Perhaps I’m naive, but they could have avoided this whole kerfluffle by simply posting an explanatory statement along with the altered graph. Any looming questions would then have been answered up front.
Oh well, live and learn….

John McDonald has nailed it . . .
“Dr. Tans data is being used to support a massive attempt to regulate our lives and potentially cost us all a huge drop in our standard of living – so his data manipulation with no peer review, within 24 hours, no documentation, no impact study, etc. tells me they are NOT a serious science organization”
Indeed. And how many other changes have been made that we don’t know about ??
Scientific organization ? I think not.
Very Mickey Mouse Operation with potentially tragic economic consequences.

Been following your posts. Surprised at the number of individuals you have gathered in such a short time.
You’ve actually hit upon a subject matter that ties opinion to facts. Not to mention credible sources.

@Jack Simmons:
It’s just the MS Excel Chart function plotting data series from spreadsheet columns. Then do a “Save as Web Page”, and it generates the charts as .GIFs.
General Question:
About the issue of constantly-rising CO2 concentrations; what were global temperatures doing 800 to 1200 years ago? Wouldn’t the lag in CO2 response to temperature changes observed in ice-core samples still be happening now, or has something happened to change all that? Are we seeing minor fluctuations from current conditions against a stronger response to a background signal from long ago? I sure don’t have an answer.

Ferdinand Engelbeen:
“the mass balance: more CO2 is emitted by humans than is accumulating in the atmosphere. That means that natural sinks (over a year) are larger than natural sources.”
I’m a bit confused by this. The consensus, amongst some, seems to be that around half of anthropogenic CO2 is absorbed by natural sinks.
But what then maintained CO2 levels before mankind started burning fossil fuels? Going by the above, one would expect that the downward slope in atmospheric CO2 would have been around the same slope (except in a negative direction), and a few hundred years of that would have resulted in little or no atmospheric CO2. This would probably have resulted in a large-scale dying-off of plants, which would in turn offset the decline in CO2 by a small amount (given that the oceans are the largest CO2 sinks)
Is there any evidence of such an event?
And, even if this did happen, how did CO2 levels recover?

Fernando,
There is some misunderstanding here: the level of oxygen is reducing, due to burning fossil fuels. The reduction can be calculated, as the amounts and types of fossil fuel which were burned are more or less known, thanks to the tax/sales inventories of many countries (there may be some underestimating due to illegal sales…). But the reduction of oxygen was slightly less than expected. This points to vegetation growth which was higher than vegetation decay over the last decade of the past century. As vegetation growth produces oxygen (and uses by preference the lighter kind of carbon, 12C), the difference between expected and measured oxygen in the atmosphere is what vegetation growth minus decay has net produced and thus is proportional to the amount of CO2 that is netto incorporated into vegetation. That amount is around 1.5 GtC/year which is going extra into vegetation.
The other point is that the incorporation of the lighter carbon isotope in growing vegetation increases the heavier 13C in the atmosphere, thus vegetation decay is not the cause of the declining levels of d13C in the atmosphere and upper oceans of the past 150 years.
Battle e.a. in Science used the O2 and 13C decline independent of each other to calculate how much CO2 was absorbed by the oceans and how much by vegetation for the period 1990-1997. Unfortunately there is no recent update of that article. See:
http://www.sciencemag.org/cgi/content/abstract/287/5462/2467

@ur momisugly niteowl:
In longer time scales, it appears that CO2 lags behind temperatures by ~800 years. Did we see warming in 1208 AD? If you believe in the MWP, then that sounds reasonable. However, with emissions today, it is probably difficult to know how much is from lag in temperatures. Someone who is better educated in respect to such things might be able to know the difference.

John McDonald and Fred,
I shouldn’t say that the Mauna Loa measurements (and for that matter a lot of other CO2 measurements all over the world) don’t have a rigourous quality assurance. Most of it is done automatically, like flagging outliers and calculating averages. Later on, more manual control is done and obvious errors are corrected. Discarding outliers from a trend is done frequently even in process control: if you react on all incoming data from a process, including outliers, one can run into deep trouble…
Flagging outliers is a part of quality control, as we are interested in more or less global averages and trends, not in local volcanic outgassing, local sugarcane field CO2 use or data from failing equipment. Local CO2 in vegetation (or volcanoes) may be of interest for biologists and scientists who want to study the carbon cycle in more detail, but there are better places to do that: midst the fields and/or forests, where some 400+ stations over the world are at work, or at the mouth of fumaroles…
If there is one data series in this world where I am pretty sure that the highest standards of data integrity and quality are maintained, then it is the CO2 data from Mauna Loa and the other 9 stations from near the North Pole to the South Pole. You should read the struggle of Dr. Charles D. Keeling to maintain quality of, and the continuous measurements at, Mauna Loa and other places against the different administrations. It really is a fascinating story:
http://scrippsco2.ucsd.edu/publications/keeling_autobiography.pdf
About the use of the Mauna Loa data: even if it is quite sure that humans are responsible for the increase in CO2, that doesn’t tell anything about the influence of the extra CO2 on temperature. That is where we differ from the AGW folks…

Has it been noticed that the updated trend now shows three months in row for decline in the trendline? Isn’t that the first time as I thought previously there had never been more than two?