Another AGW tenet is that the buildup of CO2 in the Mauna Loa Record is an accumulation of CO2 throughout the brunt of the industrial era. To make that accumulation viable, AGW advocates claim the duration of CO2 in the atmosphere is a century or more.
See my analogy posted earlier. The increase is almost entirely due to anthropogenic CO2, because that is the only CO2 flux to the atmosphere sufficiently large to counter the CO2 fluxes from the atmosphere. A huge number of measurements indicate that the oceans are a net carbon sink (start HERE and you might also figure out where Hawaii really is on that plot). The carbon isotope measurements fully support this (the observed Suess effects are consistent with the isotopic signature of fossil fuel CO2 emissions AND the amount of these emissions).
Also by implication, cogitator tries to establish a contradiction by relying on the calculated isotopic fraction he discusses next. Proof by rubbing. 2. What is the accuracy in measuring the various isotopes of C and O? Are the errors correlated between different isotopes? What is the sensitivity to temperature? What is the resulting error in the fractions? Without this information, conclusions cannot be drawn from the isotopic data.
You can read a multitude of papers that have established this technique in the determination of carbon fluxes in paleoclimate studies, modern climate studies, oceanography, land biosphere, etc. to get the answers to your questions. Such procedures are performed with instruments like mass spectrometers, and can be performed with high accuracy.
And what contradiction are you talking about?
Your reference refers to the use of isotopic ratios for the investigation of paleoclimate fluxes; the application to the modern era is more straightforward because the fluxes can be estimated directly from the measurements rather than inferred from the model.
3. You wrote, “This 14C decline cannot be explained by a CO2 source in the terrestrial vegetation or soils.” That still leaves the ocean and subsurface as possible sources, and not just man.
I didn't write that. Perhaps there are other sources, which is why I provided the next reference, where the abstract concludes with "Model calculations indicate that in 1950 industrial CO2 emissions are responsible for at least 85% of the delta C-14 decline, whereas natural variability accounts for the remaining 15%."
5. You say, “Indeed, the 13C fractions in the atmosphere and ocean surface waters declined over the past decades. This fits a fossil fuel CO2 source and argues against a dominant oceanic CO2 source.” Is your point the following from the TAR?
I believe that the TAR paragraph may refer to both 14C and 13C/12 C.
So what? BTW, is the 30% figure based on ice core data?
So... if you're insisting that the current increasing CO2 concentrations in the atmosphere are due to outgassing from warmer oceans, you're wrong. And you also need to read Sigman and Boyle 2000, "Glacial/interglacial variations in atmospheric carbon dioxide". Forgive me if you've read it already, it doesn't appear that you have.
And Vostok isn't the only ice core ever drilled.
First, what is calculated is not the isotopic fraction of the increase, but of samples allegedly representative of the whole CO2 reservoir in the atmosphere.
The isotopic ratios in either living samples (tree rings) or actual atmospheric measurements are being examined.
Second, suppose the entire atmospheric reservoir were replaced by fresh ACO2 in any time period you might choose. What does that have to do with global warming?
If the concentrations remained the same, nothing. The issue is what's causing the concentration to increase.
Third, why don’t you use the rate of total CO2 increase and the rate of 14C decrease and compute the relative concentration of ACO2 in the atmospheric reservoir? That might be interesting for the carbon cycle, but still irrelevant to global warming.
The issue is what is causing the increase in atmospheric CO2 concentration since the mid-1800s.
First, as shown in the Acquittal of Carbon Dioxide, during the paleo period the natural source of CO2 was solely the oceans. We assume that the laws of physics are invariant, so it should be true today.
Notwithstanding the huge amounts of fossil fuel CO2 emissions? So is it truly your position that natural CO2 fluxes are so large that the contribution of mankind's activities (primarily combustion of fossil fuels) is negligible?
Second, global warming is apparent, and the natural efflux of CO2 from the oceans should be increasing due to an invariant solubility relationship.
That's why you have to read Sigman and Boyle 2000. Bulletin: Increasing ocean temperatures during glacial/interglacial transitions could only be responsible for at most 10% of the observed increase in CO2. The amount of ocean warming since the mid-1800s is not even close to enough to provide the amount of CO2 increase observed. But all the other data is consistent with the amount of CO2 produced by fossil fuel burning in that period.
Third, I remain skeptical that the data show what you claim, especially without quantifying “predominantly”. You don’t measure the 13C isotope of the increase, but something between a regional concentration and the whole atmospheric reservoir. Where is calculation that takes you from the domain of the measurements to the increase?
The measurement is made on atmospheric and ocean water samples. The change in the ratio (speaking of stable carbon here, i.e., 13C/12C) is a function of the increase and indicative of the source.
Feel free to respond; I will be unable to respond again until tomorrow.