cogitator says, “I can state authoritatively that the current CO2 concentration is about 80 ppm higher than at any time in the past 650,000 years.”
This appears to be the stock, AGW comparison of the Keeling data with the Vostok record. The maximum recorded in the Vostok ice cores is about 298.7 ppmv. The Keeling record has exceeded that level by 17 ppmv for about 50 years, and most recently is at about 90 ppmv above that maximum. For the purposes here, the amounts are not as important as the duration. The Vostok samples are about 1,500 years apart. The chances of catching another epoch like the present is only 3%.
There are bigger problems. Vostok is surrounded by the cold ocean sink for CO2. Mauna Loa is in or near a CO2 chimney. It is located near a warm ocean source, and is down wind from the vast and intense west equatorial Pacific outgassing of CO2. The Vostok CO2 concentration should be markedly less than the Mauna Loa record. Reading the TAR, the climatologists do not seem to have made the calculation, and instead rely on the assumption that CO2 is well-mixed globally.
Why might CO2 be well-mixed globally? AGW modelers say that it because CO2 persists in the atmosphere, they say, for decades to centuries. But it doesn’t. The IPCC Third Assessment Report says the atmosphere contains 730 GTonnes of C. It says that leaf water absorbs 270 GT/year, that photosynthesis absorbs 120 GT/year (if that’s not included in the leaf water), and that the oceans absorb 90 GT/year. That means that 480 GT are absorbed each year, of 66% of the total in the atmosphere. Assuming it is approximately replaced, a little math shows that the mean residence time for CO2 is 1.5 years. It’s 2 years if the photosynthesis is duplicated.
In a single chart, NOAA reports CO2 concentrations from four widely space stations for 1978 to May, 2006. Included are data from Mauna Loa, the South Pole, Pt. Barrow, and Samoa. http://www.climate.unibe.ch/gallery_co2.html > ftp://ftp.cmdl.noaa.gov/ccg/figures/ > co2_mm_obs.png. These records lay right on top of each other, and that would support that Mauna Loa and the South Pole should have similar concentrations. That information is not used by the IPCC. Why?
Another version can be found here and there with only data from Mauna Loa and the South Pole, and with no explanation. The TAR shows a similar graph. The two surviving, corroborating records were produced by Keeling and Whorf. But the TAR still didn’t rely on that result for its well-mixed CO2 hypothesis. Why? Both C. D. Keeling and his son, R. F. Keeling were IPCC contributors.
In 1986, Keeling himself advised that his Mauna Loa data were regional and applied to middle layers of the troposphere. In 2001, he said “only a limited number of sampling locations are required, however, provided that they are remote from large local sources and sinks of CO2.” Here we are concerned with two sampling sources, Mauna Loa downwind from a massive CO2 source, and the South Pole surrounded by a major sink. The AGW peers ignore the warnings. Keeling also said,
>>A major challenge is to determine how time-varying sources and sinks of atmospheric CO2 reflect the interplay of natural processes and human activities, including feedbacks between the earth's carbon cycle and its physical environment. Of paramount interest is that the earth's heat balance is being altered by an enhanced greenhouse effect caused by rising concentrations of CO2 and other infrared-absorbing gases. Global warming probably is occurring as a consequence, altering the carbon cycle globally. The picture is complicated, however, because natural variations in climate also impact the earth's heat balance and the carbon cycle. Citations omitted.
What was probable to Keeling is now certain to the AGW community, proved because scientists have reached a consensus. They voted! And it was all done by models with carbon cycle.
Records of other gases, including methane concentrations and isotopic CO2 ratios, taken from different spots on the globe are distinct and non-overlapping. http://agage.eas.gatech.edu/. Why is the CO2 concentration the only gas record that doesn’t vary with location? What is the model by which CO2 concentration becomes well-mixed but isotopic CO2 ratios do not?
Finally, climatologists produce estimates of the concentration of anthropomorphic CO2 around the globe. The heaviest concentration is in the North Atlantic, carried there by the prevailing winds across the US. There are small, heavy concentrations down wind from other industrialized nations. The lowest intensity is in the western equatorial Pacific, including Hawaii. The argument must be that it, too, is well-mixed, even though the isotopic ratios that measure it are not.
The well-mixed assumption is not well-supported. If the CO2 could be made visible, it should appear as bands around the globe, moving west with the trade winds, and east otherwise, and spiraling toward the poles. This should be true in the mean just as surely as average winds and average fluxes between the ocean and atmosphere exist.
These observations are qualitative, of course. We will have to wait for climatologists to get off their bandwagon and quantify them.
Actually, I was thinking EPICA.
There are bigger problems. Vostok is surrounded by the cold ocean sink for CO2. Mauna Loa is in or near a CO2 chimney. It is located near a warm ocean source, and is down wind from the vast and intense west equatorial Pacific outgassing of CO2. The Vostok CO2 concentration should be markedly less than the Mauna Loa record. Reading the TAR, the climatologists do not seem to have made the calculation, and instead rely on the assumption that CO2 is well-mixed globally.
It is incumbent on you to show evidence indicating otherwise, if you think that assumption is a problem. Let me ask this: if CO2 was not well-mixed, would the Keeling curve show annual variability related to the annual boreal spring/summer uptake of CO2 by northern deciduous forests? Would the Keeling curve have shown a three-year response to the Pinatubo eruption if CO2 was not well-mixed?
Back to first principles: does part of your presentation rely on an assumption that the increase in atmospheric CO2 since about 1850 is predominantly due to an increase in the natural flux from oceans to atmosphere due to warming oceans?