Global Warming Potentials fail because gas concentrations are not “well-mixed”
Guest post by Dr. Vincent Gray
I came across this revealing statement on page 247 of the IPCC Third Assessment Report (2001). paragraph 4.1.4. Chapter 4
“The atmospheric lifetime is truly a scale factor relating (i) constant emissions (Tg/yr) to a steady-state burden (Tg), or (ii) an emission pulse (Tg) to the time-integrated burden of that pulse (Tg-yr). The lifetime is often implicitly assumed to be constant, independent of the sources, and is likewise assumed to represent the decay time (e-fold) of a perturbation. These assumptions apply rigorously only for a gas whose local chemical lifetime is constant in space and time such as for the radioactive noble gas radon, whose lifetime is a fixed nuclear property. In such a case the mean atmospheric lifetime equals the local lifetime: the lifetime that relates global emissions to the global burden is exactly the decay time of a perturbation.
This general applicability of the atmospheric lifetime breaks down for greenhouse gases and criteria pollutants whose chemical losses vary in space and time. NOx, for instance, has a local lifetime of 5 d in the upper troposphere; and both times are less than the time required for vertical mixing of the troposphere. In this case emission of NOx into the upper troposphere will produce a larger atmospheric burden than the same emission into the lower troposphere. As a consequence the definition of the atmospheric lifetime of NOx is not unique and depends on the location (and season) of its emissions.
The same is true for any gas whose local lifetime is variable and on average shorter than about 0.5 yr, the decay time of a north-south difference between hemispheres and one of the longer time scales for tropospheric mixing. The majority of greenhouse gases considered here have atmospheric lifetimes greater than 2 yr, much longer than tropospheric mixing times; and hence their lifetimes are not significantly altered by the location of sources within the troposphere.
When lifetimes are reported for gases in Table 4.0, it is assumed that the gases are uniformly mixed throughout the troposphere. This assumption is unlikely for gases with lifetimes <1 yr, and reported values must be viewed only as approximations. (My emphasis)
This shows why they are so concerned to fiddle the measured results of gas concentrations to try and argue they are “well-mixed” and have no variability. So all results they don’t like are suppressed as “noise”, the many previous results, publicised by Beck, are suppressed, and measurements over land surfaces are forbidden. There is overwhelming evidence that none of the gases are “well-mixed”, so all of the Global Warming figures are Phoney.
Wonderful post! I have been suggesting that the “well mixed” assumption of AGW theorists is an “a priori” assumption that lacks empirical support. Thanks for your sleuthing. Maybe we will see some valuable empirical research done in this area, though not by the AGW crowd.
Interesting. The Chileans are burning a lot of fossil fuels.
I checked a prevailing wind chart, and the concentrations seem more connected with high pressure areas than winds or human generated CO2.
http://geography.uoregon.edu/envchange/clim_animations/gifs/two_sfcwinds_web.gif
I did a quick look-up of region temp changes, and there’s very little correlation between the CO2 distribution and the long-term temperature changes. Some of the highest temp changes occurred in areas with the lowest CO2 ppm.
http://www.john-daly.com/guests/tempo196.gif
Were not talking a large difference from highest to lowest around the globe – it is pretty well mixed by most measures (delta 10ppm). Since the contributions in a warming phase are mainly from the oceans, I would say they should be fairly well mixed anyway.
Every time I see this CO2 graphic, the same question arises in my mind: If the temperature rise anomaly (whatever that is) is so well corelated with the CO2, as the AGW crowd says it is, how can the North Pole be the region where the temperature as been climbing more dramatticaly? For me is another case of a few faulty surface stations badly interpolated for the representation of an area where the measurement points are very scarce. CO2 concentration is persinstantly bellow earth’s average in that region, as you can easily see in the Map or, better, in any CO2 distribution animation sequence derived from these maps.
Thanks, Dr. Gray.
If well-mixed does not stand as a hypothesis, then the IPCC must make it an axiom, of course!
Wait a minute. Where is the rest of the article that makes the case that the graphic of atmospheric CO2 variation establishes CO2 is not well mixed? Sure the blue to red coloration makes it look like a lot, but inspecting the scale shows that there is only about 3% variation from blue to red. Does 3% variation really justify throwing out conclusions requiring CO2 be “well mixed”?
Dr. Gray, first you need to give us a mathematical description of what you call “well-mixed”.
For example, is a gas whose concentration varies by say ± 1% by location around the planet “well-mixed”?
How about a variation of ± 3% around the planet? Well-mixed or not? Or ± 5%, or ± 10%? Where is the line?
I ask because, per your colored map at the top, the CO2 concentration varies from about 378 ppmv to 385 ppmv. That gives us an average of 381.5 ppmv.
More to the point, however, the range of the variation in CO2 concentration is
381.5 ± 0.9%
Me, I’d call a variation of plus/minus one percent “well mixed”. The variation in CO2 concentration globally is less than one percent.
Which is why I’m asking about your definition of “well-mixed”. Less than one percent?
Thank you for a thought-provoking article.
w.
Dr. Gray, could you please lead me to the source of the top Figure (map)? Thanks.
If the range is 376 ppm – 386 ppm, I’d call that “well-mixed”. 10/386 < 0.3% approximation error. That's less than the inaccuracies in the equilibrium assumption and Clausius-Clapayron equation. Less as well than the approximation error in the Stefan-Boltzman equation.
This whole issue of the accuracy/inaccuracy of a whole slew of approximations needs to be addressed more systematically than has been done to date.
Great to see Dr Vincent Gray here. I remember finding your material on IPCC years ago, and finding the hatred with which you were regarded – enough to put off lesser mortals but for me it had the reverse effect, eventually.
Makes me look forward to seeing Soon and Baliunas rehabiliated here some time. And it would be nice to rerun John Daly here too. You know, the one whose death Phil Jones welcomed. These are all still relevant as ever.
Willis:
You seem to be confusing average with mean!
Although the variation is small, the areas of high concentration show a better correlation with volcanic activity than with burning of fossil fuels.
IIRC, this is only for mid-troposphere, and their conclusion was that CO2 was not well-mixed contrary to expectations, they called it lumpy, and said that they would need to understand more about why this was so by studying winds. So if this mid-trop graphic shows little variation, perhaps they meant through the three levels they measured, upper, mid and lower. They didn’t release the data for upper and lower. Why is this graphic of only one month the poster child? All those years of data gathering and this is all we get?
I did try to get the raw data but couldn’t work out the contortions to get it.
The mid-troposphere in August — planes anyone?
Good to see the Southern Cross flag here again Vincent. With you in Wellington, and Dr de Freitas in Auckland, you are spread a bit thin, when it comes to reining in those politicians in the (really) windy city.
As for the wonderful mixing of atmospheric gases; there’s the little matter of that now expurgated NOAA pole to pole annual CO2 cycling plot; from about 6 ppm p-p at Mauna Loa to about 18 ppm p-p at the north pole, and only around -1 ppm p-p at the south pole.
So this old longtooth Kiwi is not sold on the idea of good atmospheric gas mixing.
I tried telling John Key, that NZ ought to start to lead the world out of the dark ages of MMGWCC; but he sicced his Science Adviser; Sir Whatsisname on me, and the chap said he thought the science was well established. The bump on my head has finally gone away.
George
You have to wonder about the source in Antarctica, surrounded by a ring of the lowest concentrations. Looks also to be spinning off of the S. Pole like paint on a potters wheel.
Glad to see someone is addressing the “well-mixed” assumption.
That is an assumption that has always struck me as being absurd. We have a huge CO2 “active” planet, with numerous sinks and generators. Sinks and generators that shift through the day and through the year.
We have the data gathering done on an active volcano next to a tropical ocean. The data is then “groomed” to make sure it fits.
“4. In keeping with the requirement that CO2 in background air should be steady, we apply a general “outlier rejection” step, in which we fit a curve to the preliminary daily means for each day calculated from the hours surviving step 1 and 2, and not including times with upslope winds. All hourly averages that are further than two standard deviations, calculated for every day, away from the fitted curve (“outliers”) are rejected. This step is iterated until no more rejections occur. “
How we measure background CO2 levels on Mauna Loa.
I would FIRE a lab tech who pulled this type of data “manipulation”.
I have not worked with gases but I have worked with mixing liquids and solids. The “assumption” that the batch was “well mixed” has come back to sting the mix room crew too often for me to EVER trust that assumption without good scientific data to support the assumption.
Whomever came up with the globe chart must think there is some significance to the range of 376 -386 PPMV if not why make such a large color difference?
Oh and do not miss this great chart “Figure 5a. Measurements of CO2 by a continuous in-situ analyzer at a tall tower during the summer in northern Wisconsin. The top plot show the CO2 values at six different heights on the tower. “ http://www.esrl.noaa.gov/gmd/ccgg/about/co2_fig5a.png
“Well mixed” yeah right, 340ppm to off the chart (beyond 405ppm) is really well mixed I would say /sarc
From the same article I quoted in my first comment: http://www.esrl.noaa.gov/gmd/ccgg/about/co2_measurements.html
This article is completely devoid of reason. You argue nothing; you present no calculations; you present no logic; you simply make the bizarre claim that no greenhouse gas is well mixed, even while your article shows CO2 concentrations throughout the atmosphere uniform to within less than 2%. And then you deduce from that bizarre claim that “all of the Global Warming figures are Phoney”? Looks to me like you’ve simply lost the plot.
rbateman says: @ur momisugly October 2, 2011 at 5:15 pm
“You have to wonder about the source in Antarctica, surrounded by a ring of the lowest concentrations. Looks also to be spinning off of the S. Pole like paint on a potters wheel.”
______________________________________________________________________
Do not forget Antarctica has volcanoes. MAP: http://vulcan.wr.usgs.gov/Volcanoes/Antarctica/Maps/map_antarctica_volcanoes.html
Gary Pearse says: October 2, 2011 at 3:55 pm,
Yes, you are correct that the colour map at the top of this post doesn’t show a significant variation. But even this map is a smoothing of what really happens over land.
This would be why the IPCC forbids land measurements in its considerations — because it varies so much. This is also why Charles (“Dave”) Keeling chose the Mauna Loa, Hawaii location for his CO2 measurements. The ocean and altitude have the effect of smoothing natural daily (and seasonal) variations in CO2.
Please take a look at this graph of CO2 taken at the Wisconsin Tower in summer (graph from here). The CO2 varies close to land by 50+ ppm.
This graph shows changes with wind speed (graph from here). It can vary by 100ppm in one day. See the true picture now!?
Has the IPCC measured the local temperatures to see if there’s any correlation to the local CO2? No, because local CO2 land measurements are forbidden by the IPCC.
Let me ask this. What is the mechanism that does the mixing? Most man made CO2 is produced in the Northern Hemisphere I assume. So what does the mixing?
Paul Clark says:
October 2, 2011 at 5:52 pm
Paul, per your link the Wisconsin land measurement varies by about 30 ppmv over the course of a week or so, from about 340 to 370 ppmv.
If we agree with the IPCC use of “climate sensitivity” and use their values, the increase in CO2 should be equal to log(370/340, 2) *3 degrees per doubling = about a third of a degree.
A signal of that maximum amplitude is going to be very hard to find in a daily or even an hourly temperature set.
w.
Paul Clark, It is also why there was a smear campaign against Beck and his historic CO2 measurements.
Once you show the atmosphere is not “well mixed” then the CO2 measurements at Mauna Loa can not be “purged” of data that does not meet the standards:
1. The standard deviation of minute averages should be less than 0.30 ppm within a given hour….
2. The hourly average should differ from the preceding hour by less than 0.25 ppm….. See: http://www.esrl.noaa.gov/gmd/ccgg/about/co2_measurements.html
And THAT means the standard deviation of the entire data set becomes much larger and the changes in CO2 shown to be “significant” over the past years all of a sudden become “noise”
This is why the assumption that CO2 is well mixed is absolutely critical to CAGW. Without that assumption the whole argument for throwing out data is falsified and the entire data base of recent CO2 measurements fall apart because it is “Cherry picked”
AJ Strata shows a similar type of reasoning applies to the temperature data: http://strata-sphere.com/blog/index.php/archives/11420