How reliable are CO2 measurements?
What the science says...
Climate Myth...
CO2 measurements are suspect
"The Keeling curve, which is widely used to show the increase in CO2 emissions, is based on data from the top of Mount Mauna Loa in Hawaii. Mauna Loa is a volcano and it doesn’t seem to me that a volcano is the best place to be taking CO2 measurements" (disinter)
The following graph shows atmospheric CO2 levels over the last 10,000 years. It includes ice core data for CO2 levels before 1950. For values after 1950, direct measurements from Mauna Loa, Hawaii were used.
Figure 1: CO2 levels (parts per million) over the past 10,000 years. Blue line from Taylor Dome ice cores (NOAA). Green line from Law Dome ice core (CDIAC). Red line from direct measurements at Mauna Loa, Hawaii (NOAA).
Mauna Loa is often used as an example of rising carbon dioxide levels because its the longest, continuous series of directly measured atmospheric CO2. The reason why it's acceptable to use Mauna Loa as a proxy for global CO2 levels is because CO2 mixes well throughout the atmosphere. Consequently, the trend in Mauna Loa CO2 (1.64 ppm per year) is statistically indistinguishable from the trend in global CO2 levels (1.66 ppm per year). If global CO2 was used in Figure 1 above, the result "hockey stick" shape would be identical.
Figure 2: Global atmospheric CO2 (NOAA) versus Mauna Loa CO2 (NOAA).
The following video is a graphic example of where our data for CO2 levels comes from. It shows surface measurements of CO2 varying over different latitudes from 1979 to 2006. The graph is created by Andy Jacobson from the NOAA and includes a global map displaying where the measurements are coming from, a comparison of Mauna Loa CO2 to South Pole CO2 and the graph expands at the end to include ice core measurements back to the 19th Century.
Satellite data is consistent with surface measurements and present a fuller picture of global CO2 concentration. The next video shows global distribution of mid-tropospheric carbon dioxide. This data comes from the Atmospheric Infrared Sounder (AIRS) on the NASA Aqua spacecraft. Superiposed over the global map is a graph of carbon dioxide observed at the Mauna Loa observatory.
Last updated on 9 July 2010 by John Cook.
How can we be confident that the CO2 concentration measurements from the ice core samples, which may have been contaminated in some way, either historically through leakage or in the recent withdrawal process, gives a reading comprable to those from Mauna Loa? Has there been a good rebuttal to the work of Zbigniew Jaworowski in this area. I have not done exhaustive research in the area (really just debating amongst non-science friends), but one brought up this line of argument to discredit the top graph here on historical CO2 concentrations. In researching the issue of comparability and the reliability of the CO2 measurements, I found Jaworowski and few folks countering his arguments. I'm genuinely not trolling here, just interested in the topic.
ajc, which of ZJ's claims would you like a response to? Tamino responded to the "too smooth" concern here.
It's hard to take ZJ seriously, but for detailed look at the ice core CO2 process and validation, see Etheridge 1996.
and follow cites for more recent work. For a direct rebuttal, see here. The consilience of CO2 levels between ice cores from different location (eg Greenland, Antarctica) would be big hint that the method is fundamentally sound. Furthermore, the idea that AGW is based on icecore data is hopelessly wrong. ZJ would appear to be a classic case of a scientist "gone emeritus"
ajc... Watch this small section of the Richard Alley lecture and he tells it like it is on this point. Start at min 12:10.
A good way to check on claims that have been made in journal papers is to use Google Scholar to identify papers that have cited the paper and see if any of them are critical or provide evidence that answers the claims made. I this case, I found
T. GüllükF. SlemrB. Stauffer, "Simultaneous measurements of CO2, CH4, and N2O in air extracted by sublimation from Antarctica ice cores: Confirmation of the data obtained using other extraction techniques", Journal of Geophysical Research: Atmospheres (1984–2012)l Volume 103, Issue D13, pages 15971–15978, 20 July 1998
A sublimation technique has been developed to extract air samples from polar ice cores for subsequent simultaneous measurement of several trace gases by frequency-modulated tunable diode laser absorption spectroscopy. This extraction and analysis technique is shown to be suitable as an extraction method for the determination of concentrations of the greenhouse gases CO2, CH4, and N2O in air samples of ∼1–5 cm3 recovered from ice samples of 10–50 g. Air samples from the Siple ice core have been analyzed covering the period between 1772 and 1973. In addition, a few samples from two different ice cores from Vostok station have been analyzed. Our results are in a good agreement with results obtained by other researchers using melting and crushing extraction techniques. This agreement indicates that processes connected with the formation of clathrates in ice under high pressure at greater depths and their destruction after drilling are not affecting the CO2, CH4, and N2O measurements significantly.
[emphasis mine]
Which appears to provide experimental evidence directly refuting one of Jaworowski's arguments (in addition to that provided by Etheridge). Essentially the scientists that work on ice core data do know what they are doing and do their best to examine possible sources of bias or error and eliminate them, as these two papers demonstrate.
humanity can take spot CO2 measurements but this assumes homogeneous concentrations, which are not always true. The Committee has often spoken and said, on gases, most of Earth's heat is internal, the reason similar temperatures are found a certain distance below the surface no matter where they are taken. Under Antarctica or along the equator will have similar temperatures at a certain depth (I think it’s fairly shallow, also) Sunlight and surface heat causes daily weather and seasons, of course, but this cycle is on top of the underlying base, natural heat. This is what controls climate, says The Committee.
Greater CO2 and heat cause greater evaporation, more rainfall and both carbon dioxide and rainfall encourage plant growth which consumes the CO2 to produces oxygen. The equilibrium of oxygen and CO2 has been reached long ago and fluctuates along a very narrow band too small to have climate effect. This they say, is because of the principal atmospheric gas, nitrogen, which as we know, dominates.
They say CO2 emissions caused by human activity are insufficient to alter the equilibrium; the plant response to increased rain and carbon dioxide is very efficient. The proportion remains well inside the narrow band that does not affect weather.
Earth climate is affected by the magnetosphere and the planet's molten iron core, from which heat dissipates. Most of Earth's surface is ocean; heat reaches the seafloor, where we do not and cannot measure temperatures. This affects sea water temperatures and currents, much more sensitive to small changes. (liquids much denser than gases) These are the causes of the erratic weather patterns we have felt on Earth, attributed erroneously to manmade global warming.
Welcome to Sks. Please take the time to study the comments policy on this site. When you make a claim that is contrary to well known facts, then you should provide link to the sources of your information. Whatever your "committee" is, it's source of information is laughably and grossly wrong. Please dont waste people's time by commenting on an article you obviously havent bothered to read.
For the point of this article, note the linked video showing the variation of CO2 both vertically and horizontally. Note also this image which demonstrably show no such assumption of uniformity is made. You might like to also note the OCO-2 satellite which continuously measures CO2 concentration.
I suggest you take time to read some of the climate myth articles to become better informed before commenting further. And note that the extra heating from CO2 is around 100x greater than the total geothermal heat flux.
Offtopic comment has been deleted but a commentator has helpfully provided you with more information. See here
@25, heat is the last form of energy... it is not a physical object like CO2 therefore they obey completely different rules!
Hello,
Can somebody please explain why only ice core data is used for the pre-instrumental measurement period? I understand that stomatal index data has certain problems, but then so does ice core data. Fossilized stomata data is used for the more distant past, and some Holocene studies seem pretty robust and use multiple locations, e.g. Steinthorsdottir et al. (2013).
Surely any issues with the stomatal data could be taken into account and it could be combined with ice core data to make a more accurate reconstruction of past CO2 levels. Is there simply not enough of it?
Stomata studies showing high levels of CO2 in the relatively recent past are being used to suggest that current levels are not unusual in human history, even though this contradicts ice core data. I understand the obvious problems with the Beck (2007) work for example, but what about studies suggesting higher CO2 at the end of the Younger Dryas?
It's not. Temperature measurements began in 1659. Stations were added throughout the centuries since then, becoming a truly global network beginning in 1880. Multiple proxy records extend that record literally millions of years into the past.
http://www.ncdc.noaa.gov/paleo/globalwarming/instrumental.html
http://www.ncdc.noaa.gov/oa/climate/research/1998/anomalies/anomalies.html
http://www.ncdc.noaa.gov/ghcnm/v3.php
http://www.ncdc.noaa.gov/data-access/paleoclimatology-data/datasets
http://www.realclimate.org/index.php/data-sources/
http://en.wikipedia.org/wiki/Instrumental_temperature_record
Multiproxy reconstructions are now commonplace. For example, per the PAGES 2000 reconstruction, current global surface temperatures are hotter than at ANY time in the past 1,400 years, and that while the Medieval Warm Period and Little Ice Age are clearly visible events in their reconstruction, they were not globally synchronized events.
http://www.skepticalscience.com/pages2k-confirms-hockey-stick.html
From the peak temps and CO2 at the height of the Holocene Climatic Optimum some 7,000 years ago, temps and CO2 went into a long, slow decline, until about 100 years ago. Global temperatures dropped about 0.8 degrees C.
Over the past 100 years we have entirely erased that 5,000+ years of natural cooling (Marcott et al 2013), with global temperatures rising a full degree C:
http://www.realclimate.org/images//Marcott.png
http://climatedesk.org/wp-content/uploads/2013/03/marcott-B-1000.jpg
http://www.realclimate.org/index.php/archives/2013/09/paleoclimate-the-end-of-the-holocene/
http://www.sciencemag.org/content/339/6124/1198
Given that orbital forcing is still negative, and will continue to be negative for the next several thousand years, natural forcings are not responsible for this current warming period.
Please place relevant comments and questions on the pertinent thread.
@Daniel Bailey
Sorry, perhaps I didn't phrase my question clearly enough. My question was specifically about reconstructions of CO2 levels, not temperature data.
I'm aware of the multiple proxies used for temperature reconstruction, but I can't find reconstructions of CO2 levels over the last several thousand years that use anything other than ice core data, although reconstructions over millions of years use stomata and ocean sediment for the earliest periods.
Given that stomata-based data indicate higher levels of CO2, how do we know ice core data for CO2 levels is more reliable? Once local variability and other factors are taken into account, aren't stomata indices useful proxies? Are there other proxies which could be used to back up ice core CO2 results?
APT - It is easier to have a discussion when you properly cite the papers you are referring to. I assume it is this.
My understanding is that problems with stomata are much larger than with ice core and only used when ice core is unavailable. You might like to read the published comment on your reference before being so sure of the superiority of the stomata record.
There are two further points of note:
1/ the record of high CO2 at time of Younger Dryas is being presented to support that rapidly rising CO2 levels cause climate change.
2/ The isotope signatures of CO2 at YD indicate different CO2 source to what is present today.
Feel free to delineate what you feel those limitations might be and cite your sources. The ice core data are among the best we have for the past 800,000 or so years for atmospheric gases. You're going to have to do better than just an argument from incredulity.
"seem" is hardly an objective assessment.
Surely. But still an argument from incredulity. This venue deals in evidence. Since you seem bent on making an assertion about ice core CO2 data, the burden of proof is on you, the claimant, to mount an evidence-based claim and to support it with links to the primary literature.
Citation, please.
Nebulous assertion; citation please.
Off the top of my head, Ziegler et al 2013 does just that. Further, it covers the period of the past 360,000 years.
How do you know that ice core data is less reliable than stomata data?
Yep. When used with proper contexts. Which is how they are used.
There are. I gave you a link to them in my previous comment. Here it is, again.
@Scaddenp
My apologies for not giving a full reference or link to the relevant paper. I will do so in future posts. The one you've linked to is indeed the one I was referring to, and I thank you for including the published comment on it, I had read the reply to that comment but not the comment itself, which looks like it contains the kind of information I was looking for.
At no point did I say I was sure of the superiority of stomatal records. Far from it in fact. I simply requested information about them in order to be able to explain why ice core data was considered more reliable. I am also well aware that far from being an argument against AGW, that paper supports the consensus. I'm sorry to say that I find your response to my simple and polite request for information to be rather hostile in tone and not very encouraging for those seeking information.
@Daniel Bailey
Thank you for the link to the Zeigler et al. paper. That's interesting and useful.
Since you had misunderstood my previous request, I had assumed that the link to the NOAA paleoclimate data related to temperatures rather than CO2 levels, but I see know that there are data relating to other factors affecting climate. It would be useful to know which ones relate specifically to CO2 levels but I'll search through and find them.
The rest of your post is, unfortunately, unhelpful, since I wasn't putting forward an argument of any kind but simply seeking information to counter an argument put forward by someone else. As a response to a polite request for information it is, like saddenp's, rather hostile in tone.
Even if I had been trying to cast doubt on climate science, which I wasn't, this type of response is uncalled for and hardly conducive to promoting understanding.
APT... "...how do we know ice core data for CO2 levels [are] more reliable?"
Perhaps because ice core data are actually measuring CO2 concentrations. It's a direct measurement of CO2 (or as direct as you can get before Keeling). Whereas, somata are clearly only a proxy for CO2.
APT - sorry if tone appeared hostile. We get a lot of pseudo-skeptics here with faux arguments, so knee-jerk reactions are hard to avoid. You said "used to suggest that current levels are not unusual in human history," from which I thought you were implying the "skeptic" corrollary "so no need to worry" despite YD being in our pre-civilization past. Genuine inquiry is actually very welcome so apologies.
What have read that casts doubt on ice-core measurements for CO2? A reference would be helpful.
@Rob Honeycutt - Thanks. That's a good answer, my favourite so far.
@scaddenp - As someone who's defended the science on public forums, I understand the frustration of dealing with pseudo-scientists and conspiracy theorists. In fact, that was the reason for my request. However, as friendly advice, I suggest you tone it down a bit, since such defensiveness is more likely to provoke suspicion than promote understanding.
I was able to deal with the other references I was given, since some weren't even peer-reviewed science and I was able to find strong rebuttals of those that were. The only one that seemed to cast any real doubt on the reliability of ice core data was the Steinthorsdottir (2013) paper. Incidentally, there was a response to Kohler's comment on the paper, which you can read here: LINK
Having briefly read through it all, I'd still conclude that the ice-core data is more reliable, but the issue of disagreement between ice-core data and these results doesn't seem to be fully resolved.
Steinthosdottir references two papers regarding intra-ice diffusion, Ikeda et al (2000) and Ahm et al (2008). It seems to me that these might reflect problems of identifying short term variability rather than concentration in general, but I'm no expert on such things. Is this a real issue with ice core data? Is it accounted for?
[RH] Shortened link.
Thanks again for your help. These are the relevant links to the papers referenced above.
http://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/32477/1/P393-421.pdf
http://mail.geocraft.com/WVFossils/Reference_Docs/CO2_diffusion_in_polar_ice_2008.pdf
It seems to me that these papers conclude that diffusion probably doesn't have a very significant effect on ice core CO2 measurements, at least over longer timescales, but I'd appreciate it if someone with deeper knowledge and understanding of the topic could confirm that.
I also found a couple more relevant papers which I hope will be useful if anyone comes across arguments about ice core reliability or stomata records disgreeing with ice core data:
The first is a discussion of uncertainties in ice core measurements and how to deal with them:
ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/ice-cores.pdf
The second is a reconstruction using stomata data which in fact agrees with the ice core data and suggests that climate sensitivity to CO2 concentration is greater than previously thought:
http://droyer.web.wesleyan.edu/Franks_et_al_2014_GRL_new_stomatal-CO2_proxy.pdf
APT @75/76.
The two papers you link to are actually referenced by Steinthorsdottir et al., (2014) - 'Response to: Comment on “Synchronous records of pCO2 and D14C suggest rapid, ocean-derived pCO2 fluctuations at the onset of Younger Dryas”'
@MA Rodger
Do you mean the first 2 papers or the last 2 papers in post 76?
I mentioned in post 75 that the the first 2 were referenced by Steinthorsdottir, although I appreciate that without the full reference I didn't make it clear that it was from the "Response to: Comment..." paper and not from the original article.
I can't see references to the second 2 papers in either of the Steinthorsdottir papers.
APT @78, Kohler et al reference Marcott et al 2014 as being a high resolution ice core CO2 concentration record. Marcott et al in turn say:
What that means in practise is seen by considering Figure 3, where temporal resolution is indicated to be +/- 20 to 40 years at various time intervals:
Even at +/- 40 years, that is too good a time resolution to not have captured Steinthorsdottir's peak in CO2 at the Younger Dryas if it in fact existed. More importantly, the the +/- 1 ppm resolution of CO2 concentration at all ages shows the fluctuations in CO2 content to not be measurement error. They are fluctuations in the CO2 concentration in the ice. That is significant because the sharp variations in CO2 concentration shown are inconsistent with the record being more heavilly smoothed than shown. Smoothing through diffusion will reduces peaks, fill troughs, and turn "cliffs" into slopes. If the peaks, troughs and cliffs persist in the ice, the CO2 has not significantly diffused after the firn has closed.
In fact, it is definitely below par for Steinthorsdottir to simply wave her hand at possible high diffusion rates as an "explanation" of discrepancy between ice core and stomatal records. If diffusion is a problem, she ought to be able to (and ought to have) created a smoothed model of the stomatal record that reproduces the ice core record. Marcott et al did exactly that when comparing the higher reolution West Antarctic Divide data (WDC) with the lower resolution East Antarctic Divide data (EDC) in extended data figure 5:
Given this, it appears to me that the stomata data Steinthorsdottir uses is an inaccurate proxy of CO2 concentrationin the Younger Dryas.
Tom Curtis @79
Thanks for the reference and explanation. Interesting and useful.
The Keeling Curve seems almost uniquely consistent to me, compared to almost every other type of measurement in the natural world, which tends to be highly variable, regardless of long-term trends. The Keeling Curve, by comparison, is almost eerily rigid in trajectory, especially compared to variability of total carbon releases over time. It's like it's got some kind of governor that simply keeps the increase and accelleration from going any faster, no matter how much more carbon we pump into the atmosphere.
Can anyone help me understand how the Keeling Curve is so "tight", while so many other measurements have so much higher variability? Is it just because the other sinks - ocean, land, and plants - have so much more capacity that they can absorb whatever else the atmosphere can't? Even if that's a reasonable simple explanation, I still feel like I'm missing something from the 'limiter' aspect of the phenomenon.
I mean don't get me wrong, I'm figuratively poop-my-pants scared about climate change, particularly that "unprecidented rate" part. I've just recently been struck by the relatively tight natural regulation of the Keeling Curve, compared to a much greater variability I observe in almost every other aspect of nature.
Appreciate anything that might help a mostly layman level understanding of things dude wrap his head around that. Thanks!
Regarding the issue of accuracy or agreement of various sampling methods or ice cores: Dendrochronology (tree rings) provide another surprisingly rich, near continuous data source that includes decipherable clues about CO2 levels. Data from dendrochronology agrees, very strongly, with data from the ice cores.
h4x354xOr @82, the 'eerily rigid' trajectory is effectively explained by this graph:
The ratio between cumulative emissions and cumulative atmospheric increase in CO2 is explained by the equilibrium of partial pressure of CO2 in the oceans relative to the atmosphere, ie, Henry's Law (with a couple or nuances relating to the biosphere and the deep ocean).
The variation in actual atmospheric concentration from that predicted by that curve from year to year is almost entirely explained by variation in GMST and to a lesser extent precipitation, ie, by the temperature dependance in Henry's Law and by increase or decrease of global vegetation driven by changes in precipitation.
That is the bare bones explanation. Scientists specializing in the CO2 cycle have modelled the various exchanges in detail and are able to reproduce the increase in CO2 given anthropogenic emissions and GMST changes with surprising accuracy.
Thank you for the explanation, Tom Curtis. I had to get into my wayback machine and go visit my high school physics class, but the pointer towards Henry's Law helped break my metal logam, there. The annual variability is between 6-7 PPM; the annual increase is now a solid 3 PPM, and of course growing. It would be nice not to find out what will happen when the annual increase overtakes annual variability.
Again, thank you!
From the comments above, I feel that the current capability for measuring atmospheric CO2 is grossly inadequate. For example, I would think that if the Governor of California wished to concentrate on levels of CO2 in his state that might be problematic then he should have access to CO2 measurements at a number of surface CO2 measuring sites scattered across the state. He could then better determine if actions to reduce human induced CO2 emissions would have any significant impact on the overall CO2 levels in the state. He might well discover that the CO2 output from the states areas of intense vegetation could not be significantly countered by reducing the level of human induced CO2 emissions. Then again, he could receive evidence that such measures might well reduce the CO2 level to an acceptable amount.
My previous comment is based upon the idea that the current CO2 level in the atmosphere has an effect on global warming. In fact it is more likely an effect of global warming rather than a cause of it.
@Billev (86). I'm not quite sure what you are suggesting. Are you saying that gloal warming is causing a rise in CO2 and not the reason for global warming?
Billev @85 and 85,
In addition to RickG's question I am curious about why you mention that the Governor of California would care about the atmospheric CO2 levels in that State.
Identifying sources of CO2 emissions or other GHGs by satellite survey could be helpful. But other than identifying concentrated human production sources of GHGs, the level of CO2 in a region is rather 'beside the point'.
Increased CO2 is happening globally (it is seen at every location that measures CO2 levels).
The Global Warming and resulting Global Climate Changes are the problem.
Please provide more detail regarding exactly what you are suggesting or asking about.
My point is this. The Governor of California is attempting to install laws to limit the use of fossil fuels in order to reduce GHG emissions. This may prove to be costly to the citizens of California in terms of higher operating costs and the departure of manufacturers and jobs. If a better understanding of the sources of GHG (particularly CO2) can demonstrate that the laws limiting human consumption of fossil fuels will not significantly diminish the growth of CO2 levels then unnecessary costs caused by those laws can be avoided. In other words if it is found that increasing vegetation due to a warming Earth is the only significant source of increased atmospheric CO2 then the futility of costly policies to limit fossil fuel use might be avoided. To this end it would be valuable to political leaders to have much more detailed measurement and analysis of the sources of atmospheric CO2 than is now available.
Billev @ 85/89 , if you are talking about science ~ then the sources of atmospheric CO2 are already well-known (and have been, for decades).
If you are talking about politics (the best policies for abating the global warming problem, and the most speedy but economical & socially-advantageous ways of achieving zero nett carbon emission) ~ then this is not the right thread for such discussion [perhaps try one of the Weekly Digests?]. As always, you would need to give consideration to jobs lost versus jobs gained in advancing renewable-type industries & services . . . and put everything in perspective wrt past & present out-sourcing of jobs to China, Mexico, etcetera, in both the short term and longer term.
B. Your comment at #86 is bizarre. Please read Climate Myths 12 and 91.
billev @89,
Your clarifying of what you are suggesting or asking about has been helpful.
As Eclectic has pointed out, politics related to climate science can be discussed on Weekly Digests.
I can add more science related points to what Eclectic mentioned.
All global leaders, in business and politics, have been increasingly informed about the constantly improving awareness and understanding of climate science through the collective global expertise evaluating the science and consolidating summaries of scientific understanding (with regular updates - because science by its nature is constantly increasing and improving awareness and understanding).
The IPCC is the global body that does that. Many IPCC Reports have been produced, starting with the AR1 series of reports that were published in 1990. The IPCC is currently working on the AR6 series of reports planned for publication starting in 2021 with the last document of the series planned to be published in 2022.
So there is very little 'climate science' awareness and understanding that the Governor of any state (or elected official at a Federal level) would be 'unaware of'.
Consider that understanding of history of availability of awareness and understanding of climate science the next time you read about some elected official questioning how much is really understood about climate science. You should seriously question, be skeptical of, the motives of such a questioner.
Climate science has confirmed that future negative climate change consequences are being caused by the continued increase of CO2 in the atmosphere due to human activity, mainly the burning of fossil fuels. And the scientifically understood solution is to stop increasing the CO2 in the atmosphere. So every regional leadership is tasked with the responsibility of figuring out how to get their portion of the global population to stop contributing in any way to the increase of CO2 or other human activity created GHGs.
That is as far as the science goes. And that understanding is not going to be changed by new research. All evidence indicates that the urgency to stop the creation of new CO2 is only going to increase as business and political leadership fail to effectively correct the problem that has been developed.
I hope that helps you understand this issue.
billev - perhaps you are unaware of this satellite and its mission? There are several ways to determine what the increase in CO2 can be attributed to from carbon mass balance (we know pretty accurately how much FF is burned), O2 depletion, changing carbon isotope composition (FF has no C14), ocean pH. In fact nature is so far mopping up about half our emissions. More here.
alonerock from elsewhere,
Articles describing the measurement of the vertical profile of CO2 through the atmosphere include Abshire et al (2010) 'Pulsed airborne lidar measurements of CO 2 column absorption' who measured CO2 levels to 6km (their fig 10 below),
and Foucher et al (2011) 'Carbon dioxide atmospheric vertical profiles retrieved from spaceobservation using ACE-FTS solar occultation instrument' who measured from 5km to 25km (their fig 7 below).
When should we expect to see the global downturn in carbon emissions register on the Keeling Curve?
Ken the Bear @94,
I don't think the drop in emissions from Covid will be anyway near enough to register a change that will be noticed in the Keeling Curve.
Recent annual CO2 increases measured at MLO as measured by ESRL run 2010-19 +2.32ppm, +1.91ppm, +2.61ppm, +2.01ppm, +2.20ppm, +2.95ppm, +3.01ppm, +1.90ppm, +2.86ppm, +2.46ppm. Those numbers have a 90% range of +/-0.8ppm. It seems most folk are still awaiting better understanding of the effect of Covid on emissions before making an assessment on the matter but one estimate of the drop in rising CO2 levels due to Covid has been given as between 0.08ppm & 0.23ppm. So not enough to make a noticeable dent.
I'm interested in CO2 levels during the 1866-present period. Mainly because
1) we have direct observational CO2 measurements from 1866 onwards
2) The period 1866 -present is particulary interesting in terms of human development,the industrial revolution and co2.
Would it be possible to include a graph for this period with direct measurements, rather than proxy ice core data?
Of particular note is W. Kreutz, with 25,000 measurements in the period 1930-39 with a mean concentration of 438ppm.
W. Kreutz,“ Kohlensaure Gehalt der unteren Luftschichten in Abhangigkeit von Witterungsfaktoren,” Angewandte Botanik, vol. 2, 1941, pp. 89-117
orrok @96,
The work of W Kreutz you cite does not appear to have been published in English but the work features prominently within Beck (2007) '180 Years of Atmospheric CO2 Gass Analysis By Chemical Methods' which did attrach comment from Meijer (2007) & Keeling (2007) [PDF of both] who conclude saying "His work, however, contains major flaws, such that the conclusions are wrong, as they are based on poor understanding of the atmosphere," and "Unfortunately for Beck—as well as for humanity—the claims don’t stand up."
Beck's work seems to come up a lot. There are several other (reliable) places you can read about it on the web:
http://www.realclimate.org/index.php/archives/2007/05/beck-to-the-future/
http://rabett.blogspot.com/2006/10/amateur-night.html
http://rabett.blogspot.com/2008/03/beckies-as-tonstant-weader-knows-eli.html
...and an old comment here at SkS by Tom Curtis:
https://skepticalscience.com/argument.php?a=55&p=2#75463
Also note that Beck's paper was published in Energy and Environment. Not the highest quality journal.
https://www.desmogblog.com/energy-and-environment
Note that Toms comment I link to in #98 is further up this page (#53)...