Does Beck's chemical analysis of CO₂ discredit the Law Dome ice core findings?

Question

On RealC02 summarizing Ernst-Georg Beck's work, this history of CO₂ levels are posted for the 19th century:

SkepticalScience, on its "How reliable are CO₂ measurements?" page says "CO₂ levels are measured by hundreds of stations scattered across 66 countries which all report the same rising trend." and shows a far different history for the 19th century:

What explains the wide discrepancy before the Mauna Loa samples compared to Enst-Georg's for the 19th century, and which set is most accurate?

The discrepancy is detailed on A Different Perspective by Dr. Tim Ball, quoting Edgar Gartner:

Due to his immense specialized knowledge and his methodical severity Ernst very promptly noticed numerous inconsistencies in the statements of the Intergovernmental Panel on Climate Change (IPCC). He considered the warming of the earth’s atmosphere as a result of a rise of the carbon dioxide content of the air of approximately 0.03 to 0.04 percent as impossible. And he doubted that the curve of the CO₂ increase noted on the Hawaii volcano Mauna Loa since 1957/58 could be extrapolated linear back to the 19th century. (Translated from the German)

What is the scientific consensus? Is it correct that scientific consensus agrees that CO2 record for the 19th century should be reconstructed from the Law Dome Ice Core, or are Ernst-Georg Beck's results correct?

Mixing & altitudes

"coby" on ScienceBlogs claims "You can go here to see dozens of CO₂ sampling station records from sea level to mountain top, from pole to equator, that show unequivically that CO₂ spreads very evenly throughout the global atmosphere, all theory or prediction aside.", "here" being a collection of research held at the "Carbon Dioxide Information Analysis Center".

While it's obviously true that CO₂ is well mixed by infrared spectroscopy analysis at high altitudes

I can find no research invalidating samples taken at sea level; however, the source of anthropomorphic CO₂ production, coal fired power plants, are located nearer to population centers and not carbon sinks

My inexperience tells me that it seems Beck's research should be fully invalidated before it can be concluded that his research invalidates the Law Dome ice core.

Answer 1

[n.b. The original question involved Mauna Loa rather than the Law Dome, in fact the question has drifted considerably since I first answered it.]

The major problem here is that the CO₂ measurements that Beck provides are not measurements of background CO₂ concentrations, but measurements taken generally at low altitude, near to local CO₂ sources which mean the readings are not representative of the well mixed background levels of CO₂.

Ferdinand Engelbeen is a climate skeptic, whom I hold in very high regard (although I don't agree with him on absolutely everything), and has looked into Beck's work in detail and you can find his analysis here.

The best place to start is by asking why Mauna Loa was chosen as the first site at which background CO₂ measurements were made. Firstly, it is on an island a long way from any continental sources of CO₂, and the observatory is at high altitude, well above the inversion layer (which would stifle mixing of locally produced CO₂). Also the prevailing winds at night are from the land out to sea, which draws fresh, uncontaminated air from the upper atmosphere down to the observatory. Of course Mauna Loa is a volcano, but the scientists have developed a method for detecting this and deleting the affected measurements from the record (see this SkepticalScience article and this paper by Ryan, ISTR an article on WUWT on why Mauna Loa measurements are sound, but I can't find it at the moment.). CO₂ measurements are also now taken at a global network of similar sites around the world, and these are in agreement with the Mauna Loa record, which suggests that these methods are effective.

The scientists wouldn't go to the expense and hassle of collecting data from the top of a marine volcano, if they could get sensible measurements of background CO₂ in the lab at their universities in cities. Beck's data are instrumental measurements, but they are mostly taken close to the surface and in cities or places where there is likely to be agricultural contamination. This is well illustrated by fairly recent measurements (provided by Engelbeen) from Giessen, plotted along with the measurements from Mauna Loa (MLO) and two other background CO₂ measuring sites. Clearly the measurements at Giessen are heavily contaminated by local sources, as demonstrated by the very high diurnal variability.

So does Beck's work discredit the Law dome record? Well no, because again Beck is talking about measurements of surface CO₂, rather than well-mixed atmospheric CO₂. The Law dome records well mixed atmospheric CO₂ because firstly it is in Antarctica, a long way from sources of contamination from humans or vegetation, and secondly by altitude, the longest Law dome core appears to be some 500m deep.