Guest Post by Willis Eschenbach
In 2006, I lived for a year in Waimea, on the Big Island of Hawaii. From my house I could see the Mauna Loa Observatory (MLO). This observatory is the home of the longest continuous series of CO2 measurements we have. The recording station was set up by Dave Keeling in 1959, and has operated continuously ever since.
Figure 1. Mauna Loa Observatory ( 19.536337°N, 155.576248°W)
Here’s a view of the observatory:
Every time the subject of CO2 measurements comes up, people raise all kinds of objections to the Mauna Loa measurements. So I thought I’d start a thread where we can discuss those objections, and perhaps dispose of some of them.
Here are the objections that I hear the most:
1. The Mauna Loa results don’t measure the background CO2 levels.
2. You can’t get accurate CO2 measurements from samples taken on the side of an active volcano that is outgassing CO2.
3. The measurements from Mauna Loa are not representative of the rest of the world.
4. What about the Beck data, doesn’t it contradict the MLO data?
5. Keeling chose a bad location.
Before we get into those issues, let’s start by looking at the local meteorological conditions at the site. Mauna Loa is at an elevation of 3397 metres (11,140 ft) on the side of a 4,170 metre (13,680 ft) volcano way out in the middle of the Pacific Ocean. Because it is on an island, it gets the “sea breeze” in the daytime, and the “land breeze” in the nighttime.
These winds are caused by the differential heating of the land and the sea. Land heats up much faster than the ocean. So during the day, the warmer land heats the air, which rises. This rising air is replaced by air moving in from the surrounding ocean, creating the “sea breeze”.
At night, the situation is reversed. The land is cooler than the ocean. This cools the air. The cool air runs downhill along the slopes of the island and out to sea, creating the “land breeze”. Here’s a drawing of the situation:
Figure 2. Day and night breezes at Mauna Loa.
Now that we understand what is happening at Mauna Loa, let’s look at the objections.
1. The Mauna Loa results don’t measure the background CO2 levels. As you might imagine from Fig. 2, the CO2 measurements are taken only at night. Thus, they are measuring descending air that is coming from thousands of feet aloft. This air has traveled across half of the Pacific Ocean, so it is far from any man-made CO2 sources. And as a result, it is very representative of the global background CO2 levels. That’s why Keeling chose the site.
2. You can’t get accurate CO2 measurements from samples taken on the side of an active volcano that is outgassing CO2. This seems like an insuperable objection. I mean, Mauna Loa is in fact an active volcano that is outgassing CO2. How do they avoid that?
The answer lies in the fact that the volcanic gasses are very rich in CO2. At night, they are trapped in a thin layer near the ground by a temperature inversion.
To detect the difference between volcanic and background CO2, the measurements are taken simultaneously from tall towers and from near the ground, at intervals throughout the night. Background CO2 levels will be around 380 ppmv (these days), will be steady, and will be identical at the top and bottom of the towers. Volcanic gasses, on the other hand, will be well above 380 ppmv, will be variable, and will be greater near the ground than at the top of the towers.
This allows the scientists to distinguish reliably between volcanic and background CO2 levels. Here is a description of the process:
Air samples at Mauna Loa are collected continuously from air intakes at the top of four 7-m towers and one 27-m tower. Four air samples are collected each hour for the purpose of determining the CO2 concentration. Determinations of CO2 are made by using a Siemens Ultramat 3 nondispersive infrared gas analyzer with a water vapor freeze trap. This analyzer registers the concentration of CO2 in a stream of air flowing at ~0.5 L/min. Every 30 minutes, the flow is replaced by a stream of calibrating gas or “working reference gas”. In December 1983, CO2-in-N2 calibration gases were replaced with the currently used CO2-in-air calibration gases. These calibration gases and other reference gases are compared periodically to determine the instrument sensitivity and to check for possible contamination in the air-handling system. These reference gases are themselves calibrated against specific standard gases whose CO2 concentrations are determined manometrically. Greater details about the sampling methods at Mauna Loa are given in Keeling et al. (1982) and Keeling et al. (2002).
Hourly averages of atmospheric CO2 concentration, wind speed, and wind direction are plotted as a basis for selecting data for further processing. Data are selected for periods of steady hourly data to within ~0.5 parts per million by volume (ppmv); at least six consecutive hours of steady data are required to form a daily average. Greater details about the data selection criteria used at Mauna Loa are given in Bacastow et al. (1985). Data are in terms of the Scripps “03A” calibration scale.
There is a more detailed description of the measurement and selection process here.
As a result, the Mauna Loa record does accurately measure the background CO2 levels, despite the fact that it is on an active volcano. The samples that are identified as volcanic CO2 are not thrown away, however. They are used for analyses of the volcanic emission rates, such as this one (pdf).
3. The measurements from Mauna Loa are not representative of the rest of the world. Well, yes and no. The concentration of atmospheric CO2 varies by month, and also by latitude. Here is a “carpet diagram” of the changes by time and latitude.
Figure 3. A “carpet diagram” of CO2 distributions, by time and latitude.
Note that the swings are much greater in the Northern Hemisphere. Presumably, this is from the plants in the much larger land area of the Northern Hemisphere. However, the difference between the annual average of the Northern and Southern Hemispheres is small. In addition, there are smaller daily variations around the planet. An animation of these is visible here, with day by day variations available here.
Figure 4 shows is a typical day’s variations, picked at random:
Figure 4. Snapshot of the variations in tropospheric CO2. Note that the range is small, about ±1% of the average value.
In general, the different global records match quite closely. In addition to the Mauna Loa observatory, NOAA maintains CO2 measuring stations at Barrow, Alaska; American Samoa; and the South Pole. Here is a comparison of the four records (along with two methane records):
Figure 5. Comparison of the CO2 records from the four NOAA measuring sites.
As you can see, there is very little difference between the CO2 measurements at the four stations – two in the Northern Hemisphere, two in the Southern, two tropical, and two polar.
4. What about the Beck data, doesn’t it contradict the MLO data? In 2007, Ernst-Georg Beck published a paper called “180 Years Of Atmospheric CO2 Gas Analysis by Chemical Methods” (pdf). In it, he showed a variety of results from earlier analyses of the atmospheric CO2. In general, these were larger than either the ice core or the MLO data. So why don’t I believe them?
I do believe them … with a caveat. I think that the Beck data is accurate, but that it is not measuring the background CO2. CO2 measurements need to be done very carefully, in selected locations, to avoid contamination from a host of natural CO2 sources. These sources include industry, automobiles, fires, soil, plants, the list is long. To illustrate the problems, I have graphed the Beck data from his Figure 13, against the Law Dome ice core data and the MLO data.
Figure 6. CO2 data from a variety of sources. White crosses are MLO data. Three separate ice core records are shown. Photo is of Mauna Loa dusted with snow (yes, it snows in Hawaii.) PHOTO SOURCE
There are several things to note about this graph. First, there is good agreement between the Law Dome ice core data and the MLO data over the ~ two decade overlap. Second, there is good agreement between the three separate Law Dome ice core datasets. Third, both the ice cores and the MLO data do not vary much from year to year.
Now look at the various datasets cited by Beck. Many of them vary quite widely from one year to the next. The different datasets show very different values for either the same year or for nearby years. And they differ greatly from both the ice core and the MLO data.
Because of this, I conclude that the Beck data, while valuable for showing ground level CO2 variations at individual locations, do not reflect the background CO2 level of the planet. As such, they cannot be compared to the MLO data, to the ice core data, or to each other.
5. Keeling chose a bad location. I would say that Keeling picked a very good location. It not only allows us to measure the background CO2 in a very accurate manner, it provides invaluable information about the amount of CO2 coming from the volcano.
My conclusion? Most of the records in the field of climate science are short, spotty, and not very accurate. We have little global historical information on ocean temperatures, on land temperatures, on relative humidity, on atmospheric temperatures, on hurricane occurrence and strength, or on a host of other variables. By contrast, the Mauna Loa CO2 records are complete since 1959, are very accurate, and are verified by measurements in several other locations.
I’m about as skeptical as anyone I know. But I think that the Mauna Loa CO2 measurements are arguably the best dataset in the field of climate science. I wouldn’t waste time fighting to disprove them, there are lots of other datasets that deserve closer scrutiny.
[UPDATE] A reader below has added another question, viz:
6. What about Jaworoski’s claim that the ice core data has had its age “adjusted”?
Jaworoski argues that the age of the air in the ice cores has been “adjusted” to make it align with the modern data. He says, for example, that the Siple ice core data has been moved forwards exactly 83 years to make them match the Mauna Loa data.
Dating the ice core data is problematic. We can date the ice itself pretty accurately, through counting layers (like tree rings) and through studying various substances such as volcanic dust that is trapped in the ice. However, dating the air is harder.
The difficulty is that the air is not trapped in the ice immediately. The pores in the “firn”, the snow that falls annually on top of the ice are open. Air can flow in and out.
As more and more snow falls over the years, at some point the pores close off and the air is trapped. So how long does it take for the pores in the firn to seal off?
Unfortunately, as in so many areas of climate science, the answer is … “depends”. It depends inter alia on how much snow falls every year, how much of that snow sublimates (changes from a solid to a gas) every year, and even the shape and size of the individual snowflakes.
The end result of all of this is that we end up with two ages for any given thin slice of an ice core. These are the “ice age” (how old the ice itself is), and the “air age” (how old the air trapped in the ice is). The ice is always older than the air.
The main variable in that is thought to be the annual snowfall. Unfortunately, while we know the current rate of annual snowfall, we don’t know the historical rate, particularly tens of thousands of years ago. So we use the concentration of an isotope of oxygen called “d18O” to estimate the historical snowfall rate, and thence the firn closing rate, and from that the air age.
Sounds a bit sketchy? Well … it is, particularly as we go way back. However, for recent data, it is much more accurate.
So to bring this back to real data, in the ice core data I showed in Fig. 5, the air is calculated to be 30 years younger than the ice for cores DEO8 and DEO8-2, and 58 years younger for the DSS core. Is this correct? I don’t know, but I do know that there are sound scientific reasons for the “adjustment” that Jaworowski objects to .
Finally, the existence of a thirty to sixty year difference in air and ice age doesn’t make much difference in the pre-industrial levels of CO2. This is because prior to about 1800, the level is basically flat, so an error in the air age dating doesn’t change the CO2 values in any significant manner.
FURTHER INFORMATION:
Greenhouse Gas & Carbon Cycle Research Programs
Trends in Atmospheric Carbon Dioxide
How we measure background CO2 levels on Mauna Loa
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
[quote][b]dr.bill[/b] says:
June 5, 2010 at 3:44 pm
[i]HankHenry: June 5, 2010 at 2:04 pm
……..
It would be greatly appreciated if someone would enlighten me on this point because expositions that I read sometimes includes a discussion of absorption and re-radiation and sometimes omit it.[/i]
Hi Hank,
The fundamental distinctions are between ‘whole-molecule processes’ and ‘electron-transition processes’.
Garden-variety blackbody (or greybody) effects involve whole-molecule processes. These depend directly on the temperature of the molecules (which in turn depends on their speed, or more correctly, their Kinetic Energy). This has essentially nothing to do with electrons, and is described by Planck’s Law and the Stefan-Boltzmann Law which can be derived from it. The other whole-molecule processes are conduction and convection, along with the additional issue of Latent Heat, which is involved during solid/liquid and liquid/gas changes of state.
The electrons become specifically involved when photons (from some external source) are able to boost electrons within molecules from initial energy states to higher ones. The electrons “don’t like” being in excited states, and dump the energy in the form of photons of equal frequency in order to return to their previous condition. This absorption/emission process takes place in nanoseconds, and has little or no lasting effect on the Kinetic Energy (and thus the temperature) of the molecules. If a molecule has an available electron transition corresponding to the energy of the incoming photon, then it will absorb and then re-emit the energy. If no such transition is available, the photon just continues on its merry way, and the material is thus transparent to radiation of that frequency.
A bit of study on each these topics will make things clearer.
/dr.bill[/quote]
Willis Eschenbach says:
June 5, 2010 at 5:21 pm
So 90% of the downwelling radiation hitting the surface comes from the first 580 metres (1900 ft) of the atmosphere.
I am lead to believe CO2 has limited absorption bands, namely 2.7, 4.3 and 15 micrometers (µm), this amounts to about 8% of the total surface radiation. LINK
Am I safe in assuming the 90% downwelling radiation from CO2 in the first 580 meters refers to the actual absorbed radiation? i.e. something less than 8% of total surface radiation?
[Note: WordPress doesn’t support BB code. Please use HTML in posts, with arrow brackets. ~dbs, mod.]
Apologies, that post was intended for Willis, I forgot I had taken a copy of dr.bill intended for another thread. 🙁
I believe “Jaworowski”, not “Jaworoski” is correct name of that Polish scientist.
CO2 growth rate obviously has much to do with oceans. 1998 El Nino is clearly visible, as CO2 was out gassed by warm ocean surface.
http://www.climate4you.com/images/CO2%20MaunaLoa%20Last12months-previous12monthsGrowthRateSince1958.gif
More, the CO2 growth rate somehow stabilizes over time – probably it is absorbed more efficiently as oceans cools.
Great Post. I just wish you had done it before I had to figure it out for myself.
My apologies to Willis, and many of the following commentators, but I must say.
Overall there are many issues with the MLO data / method that
have been “brushed over”.
TonyB, Richard S Courtney, Ernest Beck, Pamela Gray, anne v, and many others have raised real concerns and issues that have not been dealt with sufficiently.
I hope my layman’s explanations of some of these points will help more understand the real issues with the MLO record, and it’s supposed “reliability”.
http://www.globalwarmingskeptics.info/forums/thread-702.html
(Also includes excel sheets of MLO (monthly) data plots – you may find interesting….)
In the end one thing can be said,
the raw data for MLO has never been released.
“raw hourly averages” ARE NOT raw data, that at least was finally admitted..
However, if the raw data was released now,
would we know it was the original raw data – NO.
Willis, you sure received some feedback on this one!
I asked above about the date, 1973, and the 27m mast, because your ML CO2 graph started in 1973. On further reading, the measurements started on one instrument in 1958 and a new instrument in 1973. So your graph shows the instrument that started in 1973 and was retired about 2002. It’s often interesting to look at overlap data when instruments are changed. Beck wrote extensively about this. He makes a rather good case that the 1958 start should not be stitched to the accepted reconstructions of CO2 prior to that.
I don’t know the answers, too far from the action, but as a former analytical chemist it’s a bit alarming that there was no cross-checking (a claim by by Beck) of the ML instrument used 1954-73 by manometric or wet chemical methods, which are quite accurate in the hands of a good chemist.
One has to presume (lacking description) that the 1954 instrument isolated a narrow band of IR light using interference filters. This was then shone through the air/CO2 fixed path and its intensity reduction measured. Items like interference filters and photomultiplier tubes in spectrometers drifted in those days and the similarity of the reference gas to the sampled gas would have to be very close. Because the reference gas would have a fixed composition of other gases likewater vapour, the sampled gas cannot always be an exact match and there is ample scope for error as experienced analytical chemists from those days will readily concede.
Then there’s the work of Jonathan Drake at http://homepage.ntlworld.com/jdrake/Questioning_Climate/userfiles/Ice-core_corrections_report_1.pdf plus Wagner et al http://www.pnas.org/content/99/19/12011.full.pdf
raised before on WUWT, never satisfactorily answered. Both estimate historical CO2 above 300 ppm, but they need to be studied as my summary here is too brief.
I guess overall we know very little about “Background levels” of atmospheric CO2 before 1973, certainly not before 1958.
Methane for another day is fine. Thanks for the hard yards.
anna v says:
June 5, 2010 at 9:47 pm
please ignore my rash comment above:
Which explains why in the school of CO2 they are not using anomalies, a question I wanted to ask, since even thought the initial value is high, the anomaly is similar to that measured by the Keeling lot.
The answer is: the scare factor would disappear it it could be seen that the base varies much more than the predicted CO2 increases by IPCC.
It ends in 2006 and the values are in the chorus.
________________________________________________________________________
As a quick and dirty look:
Reading off of this graph and this table for Grim, I get:
In Feb, 1999 – 369 to 377 and Grim is 364.94 a range of about 3%
In Jan 2002 369 to 384 and Grim was 369.24 a range of about 4%
In looking at the data I found it wierd —
Grim and Baring head NZ had virtually no month to month swing in the data
Christmas Island had a slight swing (3ppm)
La Jolla CA (near San Diego) and Mauna Loa have a decent swing (10ppm)
Barrow and Alert Canada have a 15ppm swing
Sary Taukum is all over the map (360 to 384ppm in a couple of years)
Sary Taukum is in Kazakhstan east of Mongolia, in the middle of Eurasia so I can understand swings in that data, but why are there monthly swings in La Jolla and Mauna Loa and none in Grim, Baring head NZ and Christmas Island?
Richard111 says:
June 6, 2010 at 1:02 am
I am lead to believe CO2 has limited absorption bands, namely 2.7, 4.3 and 15 micrometers (µm), this amounts to about 8% of the total surface radiation. LINK
Am I safe in assuming the 90% downwelling radiation from CO2 in the first 580 meters refers to the actual absorbed radiation? i.e. something less than 8% of total surface radiation?
No, that number in that reference seems to have been pulled out of thin air and is wrong. It also ignores the contribution from water.
Willis,
Sorry. Difficult to resist trying to answer other people’s questions even if they are off-topic.
Also, I tend to batch posts when time is available and did not see your first protest until after the second offending comment was posted.
While I’m here, I’d like to echo and second and third the complimentary comments of many others to your post.
After your comment “Mauna Loa CO2 measurements… I wouldn’t waste time fighting to disprove them, there are lots of other datasets that deserve closer scrutiny”, I was a little taken aback by all the people who still seemed to be ‘fighting to disprove them’.
Looking at your “carpet plot” I’m surprised that there is such a big latitudinal gradient. It suggests a northern source and a tropical sink. It’s difficult to be sure from the plot’s perspective, but levels above 50deg N appear to plunge below tropical levels during the arctic summer, even though they are the highest in the hemisphere during the winter.
Then looking at your second link to the “Carbon Tracker”, the seasonal variation in N hemisphere CO2 is positively stunning, with the arctic region suddenly dropping by 10 to 15 ppm within just a few weeks in July. It’s even more compelling seeing it in motion distributed over time and space than seeing it on a graph. WOW! Definitely a ‘keeper’! THANKS!
Richard111 says:
June 6, 2010 at 1:02 am
Please see the bottom third of http://home.comcast.net/~ewerme/wuwt/ for notes on markup codes here. It goes into more detail than the instructions below the comment typein box at the bottom of this page.
There were a lot of comments on this post so maybe I missed it, but does anyone know why the CH4 has leveled out?
RobJM says:
The cause of the CO2 increase is increasing ocean temp,(increased degassing or decreased absorption) with humans only contributing about 5% of the increase.
This is why the IPCC lies about the residence time of CO2 in the atmosphere and claims its thousands of years, if the residence time is short all the CO2 will be absorbed by the oceans.
Presumably you mean most of any extra CO2 produced by human activities. Since the CO2 in the atmosphere can’t be zero 🙂
Further both are well “stired” by everything from tides to human built vehicles.
Jbar says:
June 6, 2010 at 5:34 am
Willis,
Then looking at your second link to the “Carbon Tracker”, the seasonal variation in N hemisphere CO2 is positively stunning, with the arctic region suddenly dropping by 10 to 15 ppm within just a few weeks in July. It’s even more compelling seeing it in motion distributed over time and space than seeing it on a graph. WOW! Definitely a ‘keeper’! THANKS!
My thought on this is that the CO2 at Barrow peaks when the nearby ice cover opens up thereby exposing the atmosphere to cold water which has been isolated for several months. You’d expect this to be quite an active sink for CO2, the CO2 concentration increases as the ice reforms in the fall.
If we agree that the CO2 datasets records at MLO are accurate, we are still left with the question of what has been causing the increase.
Is it reasonable to assert that readings on an island in the middle of a vast ocean are more likely to be affected by localised changes in the ocean, rather than global changes in CO2 levels?
Put another way, is the increase in population, industrialization, pollution, etc., on the island and in the surrounding hundreds of square miles of water more likely to be the cause of the upward-trend of CO2 (and CH4)?
Jay Cech says:
Another quick calculation that can be done on the Mauna Loa data is to subtract each year’s average from the preceding to get the inter year change. One finds that the yearly change can vary extensively, for example over a short time span the year to year rate of increase can vary from 0.4 to almost 3
ppm/year (1992 and 1998 for example).
Since the fossil fuel burning of humans is increasing for the last 40 years, certainly not varying by a factor of 6, this wide variation shows that the CO2 increase in the atmosphere is due to more than just man’s combustion.
It always amazes me that the “alarmists” appear unable to apply such a simple “smell test” to their data. Feeding such data into complex models being a classic case of “Garbage In, Garbage Out”.
My compliments to Willis on yet another informative and thought provoking post. Thank you Willis and to the many commenters for their input.
There is one thing that’s bugging me about the MLO data……
China and India economies went booom on or about the 80’s. Where is the booom in the MLO data? Surely this would show up somewhere. Where? can any one point me in the right direction pls?
To put this in perspective, the number of people (and industry) from China and India who joined the industrial revolution in the 80’s dwarfs the number that kicked off the industrial revolution in the 19th C. There must be an uptick in the CO2 levels around about that time, musn’t there?
If we were to have adequate sensor coverage within each band of CO2 and nonCO2 (7 bands), I wonder what the anomaly would be over time within each band? Would we find that the system maintains an unbalanced system that over time (as in 200 years) balances itself out? It just seems to me that using one station (an accurate one in my opinion) to say what is going on within each band over a long period of time and to also use it to predict what the other bands will do in the future, seems an unsubstantiated jump to me. Earth’s flora and fauna response to CO2 anomaly likely changes, which in turn changes the CO2 anomaly, but over many years for each change, not quickly. But how does it change? IMO, we don’t know because we don’t have a randomly placed selection of sensors sufficient to cover each of the 7 bands and we don’t have a long enough record to determine % change from average.
JER0ME says:
Surely this is the other way around? Photosynthesis (releasing O2) during the day and respiration (releasing CO2) at night?
It’s more photosynthesis when there is light (daytime). Respiration (aerobic) at all times. AFAIK plant cells don’t shut down all other metabolic processes when undergoing photosynthesis. In many plants photosynthesis only takes place in specific places, not the entire plant, anyway.
#
#
Baa Humbug says:
June 6, 2010 at 7:50 am
“…..There is one thing that’s bugging me about the MLO data……
China and India economies went booom on or about the 80′s. Where is the booom in the MLO data? Surely this would show up somewhere. Where? can any one point me in the right direction pls?
To put this in perspective, the number of people (and industry) from China and India who joined the industrial revolution in the 80′s dwarfs the number that kicked off the industrial revolution in the 19th C. There must be an uptick in the CO2 levels around about that time, musn’t there?”
_________________________________________________________________________
Yes if you look at the data I summarized in a previous post.
Reading off of this graph and this table for Grim, I get:
South of the equator, CO2 doesn’t vary much. Christmas Island is between the tip of India and Austraila —
Grim and Baring head NZ had virtually no month to month swing in the data
Christmas Island had a slight swing (3ppm)
Sub tropical NH we get
La Jolla CA (near San Diego) and Mauna Loa have a decent swing (10ppm)
Far northern NH
Barrow and Alert Canada have a 15ppm swing
And Finally we get Sary Taukum is in Kazakhstan east of Mongolia, in the middle of Eurasia
Sary Taukum is all over the map, 360 to 384ppm in a couple of years or 24ppm
So I can understand swings in the Sary Taukum data, but why are there monthly swings in La Jolla and Mauna Loa so similar while there is none in land based Grim and Baring head NZ? Also why doesn’t Christmas Island have swings similar to Mauna Loa?
Gail Combs (and others)
Read my presentations http://www.kidswincom.net/climate.pdf and http://www.kidswincom.net/CO2OLR.pdf and see if it answers some of your questions. You can find my e-mail address on my website if you wish to contact me directly with further questions or comments.
Mark says:
June 6, 2010 at 7:29 am
It always amazes me that the “alarmists” appear unable to apply such a simple “smell test” to their data. Feeding such data into complex models being a classic case of “Garbage In, Garbage Out”.
The “alarmists”, as you call them, understand perfectly well why the increase is variable. It’s mainly due to upper ocean temperatures. If ocean temps are cool there is less ‘outgassing’ and greater uptake. The o.4 ppm figure probably comes from ~1992, i.e. the year after the Pinatubo eruption.
RE: Previous post
John Finn says:
June 6, 2010 at 10:46 am
I’ve just checked and I was right the 0.4 ppm increase happened in 1992 and the biggest increase happened in ……1998. here’s a surprise. Note, though there is always an increase the oceans just dampen or amplify the increase.
Many thanks for another interesting article and discussion. I have often wondered about the logic of measuring the worlds atmospheric CO2 concentration in (what I presume is) one of the worlds most active volcanic regions. So it is good to see how this is taken into account. But based on the information given here I am still sceptical of the robustness of this.
I realise I still don’t know enough about this to be making such comments, I think the only way to know myself would be to spend some time actually doing the CO2 measurement work myself (but I don’t think if I wanted to measure CO2 I’d think of going there anyway). Like so much of this kind of scientific work the basic method to allow for volcanic effects seems to make sense at first glance, but I still feel uncomfortable that it is in the heart of one of the most active volcanic regions of the world, so for example I don’t understand how we can be so sure we are not measuring volcanic CO2 that got mixed into the higher altitude air during the day, or there’s not other contamination routes we may be missing.
I am not saying I believe the measurement results are wrong, after all I presume they agree well with other measurements around the world(?), so I presume they are very likely close enough, but I think if it were me using the data for important research I’d need a lot more convincing: Despite any clever methods to overcome it, it just seems too risky to me to site the worlds most important and trusted CO2 measurement in a volcanic hotspot.
In the grand scheme of things maybe it doesn’t make a significant difference to the results (e.g. by cross checking against other sites), but as a matter of scientific principle it doesn’t feel right to me; is it really that difficult to find a better location?
Richard S Courtney says:
June 6, 2010 at 12:57 am
Editor:
I agreed to Willis’ request to discuss the possible causes of the recent rise of atmospheric CO2 concentration “on another thread”. However, there remains a steady stream of postings that present nonsensical assertions that the cause is known to be anthropogenic.
It is clearly biased to allow the posting of twaddle that asserts the cause of the recent rise is anthropogenic when it is ruled that scientific evidence and argument about the cause are ruled as being “off topic”.
I am offended that my presentation of facts is considered improper when subsequent illogical and ignorant nonsense concerning the same subject is considered acceptable. Below I copy one of several examples of the illogical and ignorant nonsense that has been posted after the facts were ruled ‘off topic’
For what it’s worth, Richard, I think you should be allowed to air your views on the subject of anthropogenic CO2 as I feekl it’s highly relevant to the general post. I’m a bit surprised, though, that you refer to views that contradict your own as “twaddle” and “ignorant nonsense” – particularly as the evidence for human influence is so strong. If ML data is correct, and I believe it’s good enough, then we have had 50 successive years when CO2 has increased and NONE when it has fallen. Regardless of ocean temperatures and other factors CO2 levels have continued a steady climb. This does not suggest natural factors are responsible. We (humans) put ~7 GtC into the atmosphere each year and the atmospheric concentration increases by ~4 GtC each year. All the talk about human emissions being insignificant is nonsense (to use your phrase) – there is more than enough to account for the measured increases.
PS which thread is hosting the resumed discussion.