I’m really quite surprised to find this paper in Nature, especially when it makes claims so counter to the consensus that model projections are essentially a map of the future climate.
The Hockey Shtick writes: Settled Science: New paper ‘challenges consensus about what regulates atmospheric CO2 from year to year’.
A new paper published in Nature “challenges the current consensus about what regulates atmospheric CO2 from year to year” and finds “semi-arid ecosystems in the Southern Hemisphere may be largely responsible for changes in global concentrations of atmospheric CO2.”
The authors find links between the land CO2 sink in these semi-arid ecosystems “are currently missing from many major climate models.” In addition, they find that land sinks for CO2 are keeping up with the increase in CO2 emissions, thus modeled projections of exponential increases of CO2 in the future are likely exaggerated.
The paper joins many other papers published over the past 2 years overturning the “settled science” of the global carbon cycle.
Climate science: A sink down under
- Nature (2014) doi:10.1038/nature13341
- Published online21 May 2014
The finding that semi-arid ecosystems in the Southern Hemisphere may be largely responsible for changes in global concentrations of atmospheric carbon dioxide has repercussions for future levels of this greenhouse gas.
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature13341.html
more here: http://hockeyschtick.blogspot.com/
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==============================================================
There’s a saying, “It doesn’t matter who sings the song as long as the song gets sung.”
I’d add, “And the more that are singing, the more it keeps ringing.”
(OK. Maybe I should have left the original alone.8-)
richardscourtney says: May 23, 2014 at 2:03 pm
Humans may be disturbing the carbon cycle but there is no evidence that we are.
——————————-
Humans may be disturbing the carbon cycle but there is no evidence that what we are doing has a significant global effect in that regard.
There …. I fixed it….heh.
A better set of questions:
One, combining all the molecules in the atmosphere that absorb and re-emit long wave infrared radiation, what is the current combined ppm compared to 50 years ago in both absolute and relative terms? Two, can that change result in a substantial change in heat that is measurable via land based sensors to the extent the change is greater than the standard instrument/human error of the measure? Three, can the water cycle slow down or speed up in response to that change such that temperature change is attenuated? Four, do reliable and valid observations (IE those that have continuity of data and maintained unchanged environment) over that time span demonstrate that hypothesis? And finally, five, if change has occurred has it been harmful, beneficial, or neutral?
It’s more funner than that, even. A recent NASA film featured here showed that daily, the CO2 absorbed by the rainforests in SA during the day matches that emitted at night. So the rainforests themselves, in situ, are “carbon neutral”. But the runoff from the major rivers fertilizes huge Atlantic phytoplankton blooms which supply much of the world’s oxygen.
Gunga Din:
At May 23, 2014 at 2:15 pm in response to my having said
you say to me
True, but my concern is that one is often forgiven for being wrong and rarely forgiven for being right.
Richard
Pamela Gray:
re your questions at May 24, 2014 at 7:14 am.
I respectfully suggest that in the context of AGW, the most important question concerning the carbon cycle is:
Would atmospheric CO2 concentration be different in the absence of the anthropgenic CO2 emission and if so by how much?
Richard
=============================================================
😎 True.
Thanks for not being silent.
LT says:
The next question is “is the ratio of atmospheric CO2 molecules trapped in a million year old air bubble from Antarctica the same as a sample taken from the top of mountain in Hawaii?”
It is: if you had samples taken at Mauna Loa over the course of ~560 years and make a time-weighted average, you would find the same CO2 level as in the air bubble enclosed in the 800,000 years old ice core of Dome C in Antarctica. This is proven for the short time -20 years- that there is an overlap between CO2 measurements at the South Pole and the high accumulation ice cores at Law Dome (1960-1980):
http://www.ferdinand-engelbeen.be/klimaat/klim_img/law_dome_sp_co2.jpg
If properly extracted and handled, ice cores contain a wealth of information of the ancient atmosphere, inclusive CO2 levels. The only drawback is that the resolution is limited by the time the pores still are open to the atmosphere, allowing the mixing of the atmosphere in the pores over many years. More basic information about ice cores:
http://courses.washington.edu/proxies/GHG.pdf
I have no idea why Richard prefers stomata data, these are proxies with their own biases and problems, while ice core CO2 levels still are unchanged (in most cases for Antarctic cores) over hundredthousands of years. If there are discrepancies between the two series, then the stomata data are certainly wrong…
BioBob says:
May 23, 2014 at 1:04 pm
let me see, 6.5 Gtc they used to say versus 9 Gtc
Humans emissions increased about every year in the past 50 years, while CO2 in the atmosphere increased with much year by year variability. But in each year of the past 50+ years, human emissions were larger than the increase in the atmosphere. Thus nature was a net, but variable sink for CO2 every year of the recent past, whatever or where these sinks might be:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/dco2_em2.jpg
where 1 ppmv = 2.12 GtC
Ferdinand Engelbeen:
In your reply to LT who asked
at May 24, 2014 at 2:39 pm you say
Say what!?
We don’t have “samples taken at Mauna Loa over the course of ~560 years” so we cannot make a “time-weighted average” over such a period.
Law Dome is rapid deposition ice and, therefore, is not indicative of the long term ice from e.g. EPICA. The CO2 data obtained from ice cores very, very different from the CO2 data obtained from real-time samples e.g. at Mauna Loa.
I gave some explanation of this in my post addressed to you on May 4, 2014 at 2:03 pm which is here.
I copy that post to here to save others needing to find it.
I here add that during the decades the firn takes to seal the air in the firn will be mixed by being pumped in and out by variations in atmospheric pressure (i.e. weather).
Also, please note my final sentence which says
The ice core data and the stomata data are each indicative and each is useful, but neither is directly comparable to results of atmospheric measurements.
That is my considered view, and I fail to understand how in your post I am answering you can misrepresent that as you do in your final paragraph where you say
I accept the indications of high atmospheric CO2 concentration and rapid variation in the concentration indicated by the stomata data. The lower rates of change indicated by the ice core data are “certainly wrong” because they are smoothed by the decades of time for the firn to solidify and, therefore, the ice core data cannot indicate fluctuations that happened over a few decades.
And I accept the variations in atmospheric CO2 concentration indicated over centuries by the ice cores and which are not available as continuous time series from stomata data.
So,
I prefer the ice core data for some purposes which the stomata data cannot provide.
And
I prefer the stomata data for some purposes which the ice core data cannot provide.
Richard
@David Ball: You say:
“As Don Easterbrook pointed out (do not recall the thread), a change from 300ppm to 400ppm is NOT a 30% increase in Co2, as alarmists constantly shout.”
ARE YOU SERIOUS?
I am waiting for someone to declare what the optimum climate is supposed to be, and upon what criteria that was determined. Then I need to know where our climate is in comparison with this metric.
If we go only on averages, on average the land upon which my present house sits would be (again, on average) be under a thousand feet of ice. How much climate change does that imply, and imply more than once?
richardscourtney says:
May 24, 2014 at 3:27 pm
Richard, you are years behind the current knowledge of ice cores. As said and proven in the previous discussions, there is no liquid layer on the ice-air boundary at -40°C and certainly not inbetween the ice crystals. There is some theoretical migration in relative “warm” coastal ice cores like Law Dome and Siple Dome at around -20°C. All what that does is broadening the resolution from ~20 years to ~22 years at medium depth. That is all. but that doesn’t change the average over that time span. Thus if stomata data show average higher values over the same time span, then the stomata data are biased, which they always are, because they measure local CO2 over land, not global in priscine air as ice cores do.
Further, even the worst resolution ice cores would show the current 100+ increase of CO2 over 160 year. Which proves that it never happens before in the past 800,000 years. But more about that later…
Who or what is responsible for the recent increase of CO2 in the atmosphere…
To begin with, the simplest answer that fits all observations in general is the right one. In this case: humans emit increasing amounts of CO2 in the atmosphere and the increase of CO2 in the atmosphere simply follows the emissions with 50-55% of the amounts emitted. More essential: human emissions fit all known observations like the mass balance, the increase of carbon in the ocean surface, in land vegetation, the 13C/12C ratio changes, the (pre-nuclear bomb tests) 14C/12C ratio changes, etc.
It is easy to find several alternative theories which fit the increase of CO2 in the atmosphere. but they all fail one or more observations. Any theory that fails even one observation simply is wrong and must be discarded.
Take e.g. the theory of Richard May 23, 2014 at 9:26 am which says that an outbreak of some undersea volcanoes can alter the pH of the oceans, emitting lots of CO2 into the atmosphere. In theory entirely possible (and may have happened at some times in the past). Besides that the human contribution and part of the extra ocean emissions then must be absorbed by vegetation (which is too limited to do that), this is proven wrong:
– make a solution of soda or baking soda. That contains a lot of carbon in the form of carbonate and bicarbonate.
– add vinegar: lots of CO2 is bubbling up. That means that the total carbon in the solution is firmly reducing.
Thus IF there is a pH decrease of the oceans caused by the addition of acidic components, then the total amount of dissolved inorganic carbon (DIC) in the ocean surface will decrease. If the reduction of pH is the result of more dissolved CO2 out of the increase in the atmosphere, then DIC will increase over time. The latter is what happens. See:
http://www.biogeosciences.net/9/2509/2012/bg-9-2509-2012.pdf
Fig.5 shows an increase in DIC with a decreasing pH…
Observations don’t support Richard’s theory, thus the theory failed and should be discarded.
Next message will give my step by step reasoning why humans are responsible for the recent increase of CO2 in the atmosphere.
Step by step, all based on observations…
Here the graphs of the past 113 years of human CO2 emissions (for the past decades based on fossil fuel sales -taxes- and burning efficiency), measurements in ice cores and firn (1900-1959) and direct measurements (1960-current) and temperature measurements (Hadcrut4 global):
http://www.ferdinand-engelbeen.be/klimaat/klim_img/temp_emiss_increase.jpg
Both CO2 emissions and increase in the atmosphere are paralleling each other with a slightly quadratic curve, while temperature is far more variable with an 1910-1945 increase, 1946-1975 flat, 1976-2000 increase, 2000-current flat. The trend of CO2 in the atmosphere simply follows the emissions and doesn’t follow the temperature trends, especially not for the flat periods. That translates in a very high correlation between CO2 increase in the atmosphere and human emissions:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/acc_co2_1900_cur.jpg
The correlation with temperature is a lot less impressive:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/temp_co2.jpg
Further, the short term reaction of CO2 on temperature changes is 4-5 ppmv/°C (seasonal, 2-3 years), up to 8 ppmv/°C (decades to multi-millennia). The latter is based on the Vostok and Dome C ice cores, which show a surprising fixed ratio between temperature and CO2 levels, where CO2 lags ~800 years during glacial-interglacial transitions and several thousands of years for the opposite transitions. This proves that there is no detectable migration in these ice cores, or the ratio between CO2 changes and temperature changes should fade away for each interglacial back 100 kyear in time… Further, even the medium resolution (~20 years) Law Dome ice core shows a similar change of CO2 in a few decades over the MWP-LIA transition:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/law_dome_1000yr.jpg
A change of ~6 ppmv for a change of ~0.8°C with a lag of ~50 years. Again around 8 ppmv/°C.
The underlying point is that there is not more than 8 ppmv/°C change which means that the increase of CO2 since the Little Ice Age from around 1600 will give not more than 8 ppmv extra CO2 for a maximum 1°C increase in temperature. That is far from the over 100 ppmv increase we see over the past 160 years. All ice cores with sufficient resolution show the same increase over the recent past:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/antarctic_cores_001kyr_large.jpg
Then another interesting item: near all inorganic carbon has an isotopic ratio between 13C and 12C around the standard: near zero per mil δ13C. Near all organic carbon has much lower ratios: the average of land plants is around -24 per mil, coal also at -24 per mil, natural gas at -40 per mil, etc. The deep oceans are between zero and +1 per mil, the ocean surface at +1 to +5 per mil, volcanoes between -4 and +4 per mil, most chalk deposits also are around zero per mil.
The atmosphere was around -6.4 +/- 0.2 per mil all over the Holocene, until around 1850:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/sponges.jpg
After 1850 there was a rapid decline in δ13C, both in the atmosphere and the ocean surface, which completely parallels the human emissions.
This completely refutes the oceans as the origin of the CO2 increase. because any substantial increase in contribution (either additional or circulating) from the oceans would increase the δ13C level of the atmosphere.
Rests the biosphere. Because it is not possible to see any difference in isotopic composition between fossil and recent organics, one need an alternative. That was found in the oxygen balance. Fossil fuel burning uses oxygen, Plant growth produces oxygen, but plant decay uses oxygen. The total balance shows that the biosphere as a whole (land + sea plants, microbes, insects, animals…) produce more oxygen than they use:
http://www.bowdoin.edu/~mbattle/papers_posters_and_talks/BenderGBC2005.pdf
The consequence is that not only the biosphere is a net sink, but also that it is a net sink for preferably 12CO2, leaving relative more 13CO2 in the atmosphere. Thus neither the oceans or the biosphere are the cause of the increase of CO2 in the atmosphere or the rapid decline of the δ13C level.
At last, there was a lot of discussion about the variability in the rate of change of CO2 with temperature. According to some (Bart, Salby), the short term variability and the long term trend over the past decades to millennia are all natural and caused by the same processes. This is not the case. Have a look at the variability and trends on Wood for Trees since Mauna Loa started their CO2 measurements.
This shows that the rate of change of CO2 is directly the result of the rate of change of temperature. The small lag (pi/2 for most frequencies) is a matter of physics: it takes time for CO2 changes to react on temperature changes.
More important, it shows that there is no contribution of the rate of change of temperature, which has no trend at all, to the trend of the CO2 rate of change. The latter is entirely the result of another process (either human emissions or natural) that increases CO2 slightly quadratic in the atmosphere, resulting in a near linear trend in the rate of change of CO2. Wood for trees has not the human emissions in its database, but if you plot their rate of change, that is near double the rate of change of the CO2 increase in the atmosphere, also near linear.
Even more important, Mauna Loa also offers the δ13C observations since 1991. If the rate of change of CO2 goes up from the oceans, then the δ13C rate of change should go up synchronized. If the rate of change of CO2 is going up from vegetation, then the rate of change of δ13C should go down, as either less uptake (more remaining fossil CO2) or more decay will give lower δ13C in the atmosphere. Here the plot:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/temp_dco2_d13C_mlo.jpg
It may be clear from the extremes (1992 Pinatubo. 1998 El Niño) that the rate of change of CO2 is influenced by changes in (land) vegetation, as the δ13C and CO2 changes are opposite to each other.
Thus the short term (1-3 years) variation in rate of change of CO2 is largely similar to temperature changes, with the biosphere as main origin. But the long term trend of the biosphere is more CO2 uptake with higher temperatures (and increased CO2 pressure) in the atmosphere. That proves that the short term variability and the long term trend are NOT from the same processes as these have opposite results.
Conclusion: the short term variation in the rate of change of CO2 is entirely natural and mostly from decreased uptake (even production) of CO2 by (land) vegetation, while the long term trend is neither from the biosphere or the oceans, which both are net sinks for CO2.
There is only one conclusion possible that fits all observations:
Almost all of the recent increase of CO2 in the atmosphere comes from human emissions.
@ferdinand meeus Engelbeen: I commend you for following the Science on this point. I look forward to the post. Thanks
You have several contributions above; thank you for taking the time to develop them. I’ll try to address each separately to avoid further confusion.
The first plot referenced above is very clear, very compelling.
The second? Completely contradictory and very confusing! Perhaps breaking the “story” into three plots may clear things, perhaps re-thinking the second graphic entirely may help. Thus, if you chose to fix “cumulative emissions ppmv” as the x-axis, present the first plot, the second becomes “time (years) vs “cumulative emissions ppmv”, and the third becomes “Global temperature” vs “cumulative emissions ppmv” – PARTICULARLY important PRIOR to 1950!
More commonly, however, people have become used to seeing “time” on the x-axis. That would require re-plotting each chart of your argument with “time” horizontally.
I think what you thought you were presenting is “change in temperature per change in CO2 ppmv”. But, the link between “change in temperature per change in time” and “change in CO2 ppmv per change in time” is missing. (That is, there is no link at all between the two since the year 950 (and the year 1950!), which might have been your point, but – if so – it was not made by these two plots.)
Okay, Let me ask this question. Which represents the actually situation better? A 30% increase or a 0.01% increase in Co2? What do you think the general public thinks when it sees a “30% increase in Co2”? The general public have no concept of the make-up of our atmosphere, never mind the proportional increase in any one of the gases. When the public sees “30% increase”, they are freaking out because they do not understand what that number actually represents. I have never met anyone in public who is actually aware that carbon dioxide makes up only 0.04% of our atmosphere. The alarmists play on this, and I get the impression that many here do not understand this either. You are talking to yourselves, and are insulated from the publics lack of knowledge on this subject.
And yes, warrenlb, I am serious. Why don’t you show me in term that I can understand.
My perspective is that the math is being used to grossly misrepresent the situation.
Robert Brown, thank for attempting to enlighten me, but I fear you completely missed my point.
Hell, the general public couldn’t tell you the difference between “carbon” and “carbon dioxide”.
Perhaps a saunter down to your local coffee shop to ask random people these questions. You will be shocked at the lack of information. “30%” is scientifically and mathematically accurate, but completely misleads.
RACookPE1978 says:
May 25, 2014 at 9:01 am
RAC, I am not sure what you mean what is going wrong with the plots…
The first plot is the increase of CO2 in the atmosphere, the total emissions and the changes in temperature since 1900 all against time over the past 110+ years. No problem with that,
The second shows the correlation between total emissions and increase of CO2 in the atmosphere, which is a near perfect fit. The steps of both are what was plotted in the first graph for each year, but now comparing both variables against each other. From a process viewpoint, that shows that an increase of CO2 increases the sink rate in natural sinks (as can be expected for the oceans, but also for land vegetation). That both show a similar curve (and hence such a high correlation) is more or less coincidence because human emissions increase slightly quadratic, both the sink rate and the increase in the atmosphere also increase slightly quadratic. If there was no increase in emissions at all, the increase in the atmosphere would flatten and go assymptotic to a new equilibrium at some high(er) level.
The third shows the chaotic correlation between temperature and CO2 increase: a huge change in temperature of halve the scale (like what happened during the 1998 El Niño) has little effect on measured CO2 levels on short term, but the full change over 110+ years should give near 100 ppmv increase. The latter is near impossible, as 1°C temperature increase of the ocean surface gives a maximum of 17 ppmv extra CO2 in the atmosphere at equilibrium and no increase in temperature or exchange rate of the deep oceans is observed. And vegetation only grows harder with more CO2…
All I wanted to show is the difference in correlation between human emissions or temperature as possible causes of the increase of CO2 in the atmosphere…
Ferdinand Engelbeen:
Thankyou for replying to my post at May 24, 2014 at 3:27 pm with your post at May 25, 2014 at 12:44 am. Your reply says in total
Unfortunately your reply is – to be polite – misguided because claiming reality is other than it is does not help.
The surface of all water ice is coated with a disordered (i.e. liquid) layer at all temperatures down to -40°C and it is the reason why ice is slippery. This adherent liquid layer was discovered in the nineteenth century by Michael Faraday and the reasons for it were not discovered until the 1990s.
I know this property of water ice is an inconvenient truth for your assertions, but it is a property of ice in the real world.
And the firn does take decades to solidify to form the ice: the IPCC says the Vostock ice takes 83 years to seal. During that time the air will be mixed in the firn by variations in barometric pressure. The effect of this mixing alone provides an alteration to ice core data which is similar to an 83-year-running-average conducted on ice which sealed in individual years. Hence, the ice core data cannot be directly compared to Mauna Loa data (measurements at Mauna Loa began in 1958 which is less than 83 years).
The stomata are created in individual years. That is not a “bias” (unless you also wish to claim the Mauna Lopa data have the same “bias”).
And you make a daft assertion about stomata data when you write
.
The air exposed to the stomata is as “priscine” as that exposed to the ice cores. The stomata and ice cores are both “over land”. And neither is “global”.
You make another strange assertion when you write
No, that would only be true if the ice acted as a sealed container similar to e.g. a glass bottle. But the ice is not like that as is shown by several facts including the large difference between the age of a cored ice sample and the age of the CO2 it contains.
Ice cores are useful proxies, but they are NOT sample bottles.
Richard
richardscourtney says:
May 25, 2014 at 12:26 pm
The surface of all water ice is coated with a disordered (i.e. liquid) layer at all temperatures down to -40°C and it is the reason why ice is slippery.
The “liquid”-like layer of water molecules is down to -33°C, at that temperature not more than a few molecules thick. At -40°C it is zero. Inbetween the ice crystals there are no liquid layers at all even at less cold temperatures. Even pushing two ice balls together reforms the liquid-like layer of each into a more solid layer, making that removing both from each other needs far more force.
But that all is of no interest for the value of ice cores for historical CO2 levels. Of interest is if the CO2 levels changed over time either by selective rejection at closing time or by migration. The answer on the first item is no (but it is yes for oxygen and some other small molecules). The answer on the second item is: very small for “warm” coastal ice cores and unmeasurable for the colder inland ice cores over the full 800,000 years of Dome C.
the firn does take decades to solidify to form the ice
Depends of the accumulation rate: the high accumulation rate Law Dome ice cores have their bubbles sealed after ~40 years, where the average CO2 level is only 7 years older than at the atmosphere, and the bulk represents a spread (= resolution) of only 10 years, with a long, small tail of up to 40 years old CO2. The Vostok ice core needs hundreds of years to seal and the average resolution is ~600 years. For the Dome C ice core the resolution is ~560 years.
Hence, the ice core data cannot be directly compared to Mauna Loa data
As I have said before, the ice core data can be compared to the time weighted average of Mauna Loa data, if you take samples over the same time span as the resolution of the ice core. For the Law Dome ice cores, you only need 10 years of samples, which is sufficient to have 20 years of direct overlap between Mauna Loa (in fact South Pole) CO2 data and Law Dome ice core CO2 data. For the Dome C ice core, you need 560 years of samples. Thus the Mauna Loa data series is not long enough to give that answer.
The stomata are created in individual years. That is not a “bias” (unless you also wish to claim the Mauna Loa data have the same “bias”).
Stomata data are measured on leaves which grow on plants which grow by definition on land in a CO2 rich atmosphere which is average higher than “background”. The latter is measured over ice where no volcano or plant is present for thousands of km around. The average CO2 level on land can change with hundreds of ppmv within a day or even as monthly averages. Here the monthly CO2 averages for a semi-rural place (Giessen) which is comparable to many places where stomata samples are taken:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/giessen_mlo_monthly.jpg
The stomata data bias can be compensated for by calibrating the stomata data to ice cores and direct measurements over the past century, but there is not the slightest knowledge how the local bias changed over previous centuries, due to land changes in the main wind direction…
No, that would only be true if the ice acted as a sealed container similar to e.g. a glass bottle. But the ice is not like that as is shown by several facts including the large difference between the age of a cored ice sample and the age of the CO2 it contains.
For CO2, the ice core IS a sealed container, as good as a glass bottle, if the temperature is low enough. The difference between the age of the ice and the average age of the enclosed air is a matter of open pores still in direct contact with the atmosphere while the snow accumulates. That makes that the average gas age is a lot younger than the surrounding ice. That has nothing to do with any migration after the bubbles are sealed…
Ferdinand:
Thankyou for your post at May 25, 2014 at 2:22 pm in response to my post (immediately above it) at May 25, 2014 at 12:26 pm.
Others can assess our arguments for themselves, but I point out that your acceptance of ice core data is similar – and is wrong for similar reasons – to the acceptance of tree ring data by Michaekl Mann.
I repeat
Ice cores are useful proxies, but they are NOT sample bottles
and I add
No sample obtained from one place provides a global indication.
Richard
richardscourtney says:
May 26, 2014 at 12:32 am
Richard, the scientific definition of a “proxy” is a variable which is correlated to another variable which may be used as an approximation of the second value. Ice cores CO2 thus is not a proxy, as that are direct measurements of the desired value, with a repeatability of +/- 1.2 ppmv (1 sigma). The only drawback is that these values are averaged over 10 to 600 years, depending of the local accumulation rate.
Stomata data are proxies, as the stomata density roughly (the repeatability of the stomata proxy is +/- 10 ppmv within a limited range) reflects the average local CO2 level over the previous growing season, thus is influenced by local variations of CO2 caused by plant growth/decay, landscape changes,… in the main wind direction. And other influenting factors like drought, wind direction, nutritients,… may have changed over the centuries.
Thus if there is a discrepancy between the average CO2 levels measured in ice cores over the resolution time span and calculated from stomata data over the same time span, then there is no way to prefer the stomata data over the ice core data.
No sample obtained from one place provides a global indication.
Come on Richard, you know better than that. In 95% of the atmosphere: over all oceans from the North Pole to the South Pole and over land in deserts or everywhere above a few hundred meters you can measure the same CO2 values within +/- 2% of full scale. Even the +/-2 % is largely seasonal in the NH and a matter of lag between where the main (human) sources are and the distribution time needed to reach altitudes and the other hemisphere. Here the yearly averages for several places:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/co2_trends.jpg and
http://www.ferdinand-engelbeen.be/klimaat/klim_img/co2_trends_1995_2004.jpg
It doesn’t matter for any effect of CO2 (as far as there is an effect) on temperature if the local level in the bulk of the atmospheric column is 392 or 408 ppmv, as even a doubling from 280-560 ppmv only gives a theoretical increase of 0.9°C.
Ferdinand:
No. Your claim that ice cores take samples is wrong. And your repetition of your claim does not make it right.
As I said, if your claim were right then there would be no ice age/gas age difference. But there is.
And if ice cores provide ‘global’ data then stomata data must also be ‘global’ – and for the same reason – if as you say ice cores provide ‘global’ data because
Richard
Ferdinand:
PS. Use whatever “theory” you want to assess the correlation of CO2 to temperature because I can give you other theories which provide different indications. Your theory cannot be used as confirmatory evidence of itself.
Richard