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Climate Hustle

Understanding the CO2 lag in past climate change

Posted on 5 January 2011 by Anne-Marie Blackburn

Earth’s climate has varied widely over its history, from ice ages characterised by large ice sheets covering many land areas, to warm periods with no ice at the poles. Several factors have affected past climate change, including solar variability, volcanic activity and changes in the composition of the atmosphere. Data from Antarctic ice cores reveals an interesting story for the past 400,000 years. During this period, CO2 and temperatures are closely correlated, which means they rise and fall together. However, changes in CO2 follow changes in temperatures by about 600 to 1000 years, as illustrated in figure 1 below. This has led some to conclude that CO2 simply cannot be responsible for current global warming.

Figure 1: Vostok ice core records for carbon dioxide concentration and temperature change.

This statement does not tell the whole story. The initial changes in temperature during this period are explained by changes in the Earth’s orbit around the sun, which affects the amount of seasonal sunlight reaching the Earth’s surface. In the case of warming, the lag between temperature and CO2 is explained as follows: as ocean temperatures rise, oceans release CO2 into the atmosphere. In turn, this release amplifies the warming trend, leading to yet more CO2 being released. In other words, increasing CO2 levels become both the cause and effect of further warming. This positive feedback is necessary to trigger the shifts between glacials and interglacials as the effect of orbital changes is too weak to cause such variation. Additional positive feedbacks which play an important role in this process include other greenhouse gases, and changes in ice sheet cover and vegetation patterns.

The only conclusion that can be reached from the observed lag between CO2 and temperatures in the past 400,000 years is that CO2 did not initiate the shifts towards interglacials. To understand current climate change, scientists have looked at many factors, such as volcanic activity and solar variability, and concluded that CO2 and other greenhouse gases are the most likely factor driving current climate change. This conclusion is not based on the analysis of past climate change, though this provides key insights into the way climate responds to different forcings and adds weight to the several lines of evidence that strongly support the role of greenhouse gases in recent warming.

This post is the Basic version (written by Anne-Marie Blackburn) of the skeptic argument "CO2 lags temperature". This argument actually peeped its way into the top ten during December but then "We're heading into an ice age" shouldered its way back to the #10 spot (so there's a real dog fight between those two to climb over each other in the rankings).

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Comments 151 to 200 out of 246:

  1. gallopingcamel

    And herein lies our problem I think - for you, an unsubstantiated claim seems to have equal weighing to that of a scientific theory which is supported by multiple lines of independent evidence. This is not how it works in science. Those who don't accept the theory of anthropogenic climate change have systematically failed to show that the theory is deeply flawed or that some other mechanism can account for all the observations we have. You don't really have a case, in other words.

    When it comes to science, people are entitled to their opinion but not to their facts.
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  2. Variation in the Earth's Orbit: Pacemaker of the Ice Ages

    5) The dominant, 100,000-year climatic component has an average period close to, and is in phase with, orbital eccentricity. Unlike the correlations between climate and the higher-frequency orbital variations (which can be explained on the assumption that the climate system responds linearly to orbital forcing), an explanation of the correlation between climate and eccentricity probably requires an assumption of nonlinearity.

    6) It is concluded that changes in the earth's orbital geometry are the fundamental cause of the succession of Quaternary ice ages.

    7) A model of future climate based on the observed orbital-climate relationships, but ignoring anthropogenic effects, predicts that the long-term trend over the next sevem thousand years is toward extensive Northern Hemisphere glaciation.
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    Moderator Response: [Daniel Bailey] It is those anthropogenic effects which are key. Evidence exists that future ice ages may be delayed by up to half a million years by our burning of fossil fuels.
  3. Variation in the Earth's Orbit: Pacemaker of the Ice Ages
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    Moderator Response: [muoncounter] There is an ample discussion of whether or not we are heading for an ice age here. Most of the 'pacemaker' conversation has already occurred there.
  4. I must confess some confusion owing to the proliferation of moderators, it reminds me of the wrestler who was doing well until the referee clobbered him with a folding chair. I got used to Daniel Bailey but now there is "muoncounter". Whatever happened to John Cook?

    KR asks for evidence which I have been providing liberally on this thread.

    Let me try again with Daniel Bailey's comment (#117). My original response (#133) got deleted. DB's first point:
    "In order to drive acceptance, your Greenland CO2/temperature research will also have to explain the mass loss we can measure, as shown here:"

    My explanation is that the mass loss could be related to the >2 Kelvin temperature increase since 1850, clearly shown in my data. See:
    http://diggingintheclay.files.wordpress.com/2010/12/coastal-average.png

    DB's 2nd point rests on the superficial correlation between HADCRUT3 and CO2 concentration in the atmosphere once the latter variable has been exaggerated by scaling tricks. Correlation in itself proves nothing and in this case the correlation is only good over a short timespan (~1975 to 2000).

    The data I presented for Greenland and Ned's data for arctic Canada shows a strong cooling trend starting around 1934 and ending more than 50 years later. Measurements taken at high latitudes should magnify temperature trends so one should take them seriously. During those decades when temperatures are falling at high northern latitudes, CO2 concentrations are rising monotonically. I call that an "anti-correlation".
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    Moderator Response: [Daniel Bailey] Your original comment contained an accusation of dishonesty, which is a violation of the Comments Policy. Keep your comments on the science, ideally supported by peer-reviewed sources and avoid personal attacks and all will be well.
  5. gallopingcamel

    And people have already explained to you that regional variations can usually be explained by regional phenomena, such as changes in ocean or atmospheric currents - it in no way invalidates the claim that higher levels of CO2 will in all likelihood lead to increased global temperatures, which is what we are observing. Your exercise is futile.
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  6. RSS TLT trends from 1979 til present:



    Says it all really....

    Now moving on, please!?
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  7. gallopingcamel - Thank you for returning to a discussion of the data.

    Looking at your coastal stations plot (which is interesting), it is still just a tiny selection of regional data - global warming is just that, 'global'. I would have to say that regional data can only be used to discuss regional issues, which include the influence of changing weather patterns, jet streams, currents, PDO, etc. You received a moderator comment to that effect when you first posted the coastal station data.

    I have to say that I cannot tell what point(s) you are trying to advance, though. You first indicated that you disagreed with Blackburn and Severinghaus (in a fashion that should have gotten that post deleted).

    You then posted that you saw how CO2 acted as a feedback on glacial time scales, but stated that "the effect of CO2 is subtle, not dominant", overlooking the point of the thread, which is that CO2's role as a feedback in glacial climate changes does not invalidate it's role as a forcing in modern times. In fact, it provides more evidence demonstrating how CO2 has a forcing effect presently.

    Next, selecting a very small data subset of coastal Greenland stations, you argue here that you don't see a correlation between CO2 and temperature.

    As a side trip, when posting heats up, you throw up a link to someone's PowerPoint (unsourced, unreviewed, and basically an assemblage of well known skeptic fallacies).


    Again, cherry-picking tiny data subsets won't give you enough information to argue either against or for CO2 effects. And if you wish to argue that CO2 is weak, or that CO2 doesn't correlate with temperature, please take that discussion to one of those threads.
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  8. @gallopingcamel

    I must confess some confusion owing to the proliferation of moderators

    Nobody playing by the rules and acting in good faith should be confused by a "proliferation of moderators". You simply are saying that you have an strategy here and it must take into account what moderators allow.

    @gallopingcamel

    Some scientists have indeed concluded that CO2 is driving modern climate change but there are plenty of us who disagree.

    What is an "us"? a scientist? Are you trying to say that you're a scientist? Are you playing with words and your "plenty of us who disagree" means "pseudo-skeptics" but you're doing it in the hope somebody will think there's a majority of scientist thinking so?

    @gallopingcamel

    Do you understand the variables in the Y-axis of the figure you are linking? Could you explain what is it?
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  9. apiratelooksat50,

    You have steadfastly refused to look at the content of the original post, or the understand the mechanisms behind past and present warming and cooling beyond the most simplistic approach to the subject. This is why you continually fail to understand what is being discussed.

    Without repeating all of the details that I've now listed multiple times, and simply summarizing:

    1) In the past, orbital changes have initiated a swing towards a glacial or interglacial period. Changes in albedo resulting from these orbital changes are the actual initial forcing. Further changes in albedo, as well as in CO2 and H2O, constitute strong, very slowly developing positive feedbacks which are absolutely necessary for turning the initial, weak, and insufficient forcing (from albedo changes, which in turn come from orbital changes) into the temperatures swings necessary to move either into or out of a glacial period.

    2) The current, artificial injection of CO2 into the atmosphere is in no way comparable to the move into or out of a glacial period, and any attempt at a comparison is fallacious. One simply cannot draw conclusions from past events without taking the time to understand the several mechanisms involved, to recognize and consider the differences, and to think things through beyond the most childishly basic level of "gee, this never happened before, so it can't happen now."
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  10. Alec Cowan (@159), you said:
    "What is an "us"? a scientist? Are you trying to say that you're a scientist?"

    I was a scientist for 12 years, living on US government research grants. What I did was not "rocket science" (it was way more complicated than that). If you really want to know more, my post on Greenland was done using my real name. The "gallopingcamel" moniker stems from my days playing wing three quarter at Cambridge University owing to my ungainly running style.

    George Bernard Shaw once said "“Those who can’t do, teach.” I have passed beyond the ability to do very much so I teach. Please feel free to sign up for one of my courses; I guarantee that you will learn something useful. I love abrasive students as they keep the others awake. Here is my course schedule:
    http://www.bdidatalynk.com/PeterMorcombe.html
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  11. KR (@157),
    Your objection to the coastal Greenland data makes sense but please remember that I am concentrating on stations at high latitudes for a good reason. Temperature changes in high latitudes are several times greater than those measured at the equator.

    My Greenland analysis is just a start. I am working on arctic Canada and Russia. Ned has already posted results for Canada:
    http://www.skepticalscience.com/twice-as-much-canada.html

    I plan to verify Ned's plot although I don't expect to find much fault with his work which correlates well with my Greenland analysis.

    My next objective is to plot the arctic stations in Russia. Once that is done, the coverage will include the instrumental data for at least five times more stations than are included in NOAA/GHCN, NASA/GISS, UEA/HADCRUT and NCAR.
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  12. Anne-Marie Blackburn, (@155),
    Please be patient with me. It will take some time for me to extend my analysis to all land stations in the northern hemisphere.

    When the analysis includes Greenland, Canada and Russia it will no longer be a case of "regional phenomena".

    You say:
    "Your exercise is futile."

    You have been watching too much "Sci-fi" with the Vogons and the Borg.
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  13. @GC: "It will take some time for me to extend my analysis to all land stations in the northern hemisphere."

    ...not to mention getting your results peer-reviewed and published.

    I mean, we're not just going to take your word for it, you know?
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  14. @GC: Then again, it's good to see you accept Ned's plot, considering it clearly shows a strong warming trend in the polar region.

    I thought you were a skeptic, but it seems you're finally coming around to reason.
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  15. @gallopingcamel #160

    I hope moderators won't delete your message. Reading your words I instantly recognized the breed, the kind that combine their practical ability working with trafos (local trade jargon for transformers) with the tongue of a Dale Carnegie to get to a position in the cabinet of ministers -or at least try to-. Let me guess: playing golf to meet the right people, aren't you? You tag the label science to your activities, apparently most combining technical abilities, improvisation, marketing, flexibility and the personal gusto for adventure; pretty much what you are trying to do here and in the whole subject of AGW, to no avail, I'd add.

    Back to what is needed in climate science you were ask to not invent your facts and to mind your P's and Q's. You clearly failed with what you tried to substantiate with the graphics in #134 because of what a scientist or a "scientist" wouldn't have failed: identify their variables, don't let themselves misguided by an eye getting apparent correlations that used horizontal and vertical displacements simultaneously, etc.

    When you decide to stop cherry picking your regions and extrapolating local tends into global trends we will be able to continue a debate. Meanwhile you'll only get comments regarding your methodology because you have had little to say until now and saying it loud didn't make more of it.
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  16. archiesteel, (#163 & 164),
    The IPCC (AR4) says that there has been ~0.8 degrees Celsius of warming since 1850. The warming in Greenland has been about three times greater.

    The world is warmer than it was three hundred years ago and we should all be thankful for that.

    While I have many patents and peer reviewed papers, my climate work is amateur so I will respect the opinions of other amateurs.
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  17. gallopingcamel wrote : "The world is warmer than it was three hundred years ago and we should all be thankful for that.

    While I have many patents and peer reviewed papers, my climate work is amateur so I will respect the opinions of other amateurs."



    Firstly, you should read more on Skeptical Science, especially Positives & Negatives of Global Warming, and Can Animals & Plants Adapt to Global Warming ?.
    You should also have a look at this WIKIPEDIA page, which has lots more links which go against your belief.

    Secondly, your last paragraph (the second one I have copied above) shows where you are going wrong : you would do best to respect the opinions of the experts, while treating the opinions of amateurs with healthy scepticism - especially if they go against the opinion of the majority of experts and if they claim that they have the right answer that everyone has missed (or which they will 'prove' at some unspecified time in the future). Such amateurs are rarely as well-informed or competent as they believe themselves to be.
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  18. "Why glaciation occurred in the distant Paleozoic and the recent Pleistocene is a matter of debate and conjecture. [ -edit- ] The idea that the Earth must be "saved" from warming, which would endanger life itself, is thus farcical."
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    Moderator Response: [Daniel Bailey] Please refrain from just quoting some other source, especially without attributing that source or providing some kind of summation as to why that source is relevant to the topic of this discussion. Otherwise you are in violation of the Comments Policy. Thanks for your cooperation in this matter.
  19. On secular, millenarian and larger time scales astronomical
    oscillations and solar changes drive climate variations. Shaviv’s theory [2003] can explain the large 145 Myr climate oscillations during the last 600 million years. Milankovic’s theory [1941] can explain the multi-millennial climate oscillations observed during the last 1000 kyr. Climate oscillations with periods of 2500, 1500, and 1000 years during the last 10,000 year (the Holocene) are correlated to equivalent solar cycles that caused the Minoan, Roman, Medieval and Modern warm periods [Bond et al., 2001; Kerr, 2001]. Finally, several other authors found that multisecular solar oscillations caused bisecular
    little ice ages (for example: the Sp¨orer, Maunder, Dalton
    minima) during the last 1000 years [for example: Eddy,
    1976; Eichler et al., 2009; Scafetta and West, 2007; Scafetta, 2009, 2010].

    Nicola Scafetta, Empirical evidence for a celestial origin of the climate oscillations and its implications
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  20. #169: From your linked Scafetta paper:

    Irregular cycles with an average period of about 20 years are clearly visible ... . These cycles are determined by the synodic period of Jupiter and Saturn, ... A longer secular cycle of about 178 years, which is mostly determined by the synodic period of Uranus and Neptune (about 171.4 years), is also present ...

    This has nothing to do with Milankovitch cycles. Is it your contention that earth climate can be driven by anything but anthopogenic CO2?
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  21. Sphaerica @159
    Unfortunately, my original comment that you responded to was deleted and I'm not sure why.

    We agree on the following:
    1.) Changes in orbital cycles have historically initiated both warming and cooling periods.
    2.) CO2 is a greenhouse gas and contributes to the warming of the Earth making the planet liveable.
    3.) CO2 levels and temperature levels appear to be linked and have multiple feedback mechanisms.
    4.) Climate is dynamic rather than static.

    If you've answered this question before, I apologize.

    "If the human contributions of CO2 from the combustion of fossil fuels had never occurred, what would the climate be like now and what changes could we expect?"
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    Moderator Response: [Daniel Bailey] That comment you refer to was in violation of the Comments Policy due to All-Caps and ideological statements.
  22. 171, apriatelooksat50,

    I'm not sure where you're going with the question, or the point of it. I'm also quite unsure how to answer, since I know of no studies that have addressed the question, so any answer on my part would be pure conjecture.

    But given the four points that we agree upon, do you also agree on the following:

    5) During normal changes between glacial and interglacial periods, the change in CO2 lags the change in temperature, and yet is also itself an important factor in both raising and lowering temperature.
    6) During the current period, we are violating the usual pattern by artificially raising CO2 levels dramatically in a very short time frame, relative to the usual glacial/interglacial changes.
    7) Because of our understanding of how CO2 affects temperature and climate, we should not expect such a dramatic change to be inconsequential.
    8) The only reasonable effect to expect would be a dramatic increase in global temperatures.

    Given this, the "temperature lags CO2" argument against CO2 induced climate change is an invalid one.

    Do you agree?
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  23. apiratelooksat50 (#169),
    If the cycles you quote provide a better explanation for past climate change than CO2 over a wide variety of timescales, what is their predictive power?

    David Archer has made predictions for the next 500,000 years based on his CO2 driven models:
    http://climatechangepsychology.blogspot.com/2010/01/upcoming-ice-age-has-been-postponed.html

    Has anyone done anything similar with the drivers you mention?
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    Moderator Response: [Daniel Bailey] The link you provide is to a guest article by John Cook on Tenney Naumer's blog, 'Climate Change: The Next Generation'. The correct link to the Archer 2005 paper is here.
  24. apiratelooksat50, your question "If the human contributions of CO2 from the combustion of fossil fuels had never occurred, what would the climate be like now and what changes could we expect?" is answered by the first graph in the Advanced tabbed pane of the argument "It's Not Us."
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  25. Sphaerica @172
    Per your request:

    5) During normal changes between glacial and interglacial periods, the change in CO2 lags the change in temperature, and yet is also itself an important factor in both raising and lowering temperature.

    CO2 is a factor, but the importance relative to other factors has yet to be determined.

    6) During the current period, we are violating the usual pattern by artificially raising CO2 levels dramatically in a very short time frame, relative to the usual glacial/interglacial changes.

    I will agree with this, though I believe violate is too a strong word and has negative implications.

    7) Because of our understanding of how CO2 affects temperature and climate, we should not expect such a dramatic change to be inconsequential.

    Agree, but the consequences have yet to be determined. Atmospheric CO2 rates are higher than in the recent past, but temperatures are still normal.

    8) The only reasonable effect to expect would be a dramatic increase in global temperatures.

    Disagree. If CO2 was a major driver, temperatures would rise indefinitely in a runaway greenhouse effect. It has never happened in 500 million years, so either a mystery factor stops the runaway greenhouse effect, or CO2 is a minor force.
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  26. @apiratelooksat50: "I will agree with this, though I believe violate is too a strong word and has negative implications."

    That opposition on your part is political, I'm afraid.

    "Atmospheric CO2 rates are higher than in the recent past, but temperatures are still normal."

    Temperatures are increasing dramatically. I fail to see what is "normal" about this.

    "If CO2 was a major driver, temperatures would rise indefinitely in a runaway greenhouse effect."

    Wrong. Positive feedback does not necessarily lead to runaway greenhouse warming. Please read this before commenting further on the subject.

    So, unless you come up with some unheard new science, will you admit you are wrong on this? We've lost enough time debunking the same old myths for your benefit...
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  27. @GC (#166): "The IPCC (AR4) says that there has been ~0.8 degrees Celsius of warming since 1850. The warming in Greenland has been about three times greater."

    Yes, we all agree on this.

    "The world is warmer than it was three hundred years ago and we should all be thankful for that."

    Irrelevant. We are not debating whether or not the fact that it's currently warmer than the LIA is a good thing or not. We are debating the risks caused by such unprecedented human-made warming, especially with regards to the future. You see, I care about future generations. I suggest you start caring as well.

    "While I have many patents and peer reviewed papers, my climate work is amateur so I will respect the opinions of other amateurs."

    Patents and peer-reviewed papers in optics are irrelevant to the current debate. As others have said, you should be *more* critical of amateur opinions, especially if they go against the established science. I know the idea that the underdog is right has a romantic appeal to it, but more often than not that's not the case in science.
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  28. Pirate @ 175 If CO2 was a major driver, temperatures would rise indefinitely in a runaway greenhouse effect. It has never happened in 500 million years, so either a mystery factor stops the runaway greenhouse effect, or CO2 is a minor force.

    Huh?. One minute you teach environmental science, the next you don't understand either the geologic and biologic carbon cycles, nor Milankovitch cycles. And now it's the runaway Greenhouse Effect?. Where do you teach?.
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    Moderator Response: All further runaway warming omments by everybody must be on either the runaway warming Argument or the runaway warming Post. To find those, type runaway warming into the Search field at the top left.
  29. #175: "the importance relative to other factors has yet to be determined."

    Actually, it has been determined; its called forcing. See How CO2 warming is driving climate. For a completely different approach that also finds that increasing CO2 results in warming, see Physical chemistry.

    "we are violating the usual pattern ... I believe violate is too a strong word "
    Is there anything natural about the right hand side of this curve? (Although it's usually Yooper who points to this graph). Breaking our environment out of the comfortable zone we as a species grew up in should not be taken lightly.

    "the consequences have yet to be determined."
    Ah, that old dodge. If we can only wait a few more decades, we'll see ... Busted in Its not bad and Extreme weather, among other threads.

    At the end of the day, all your arguments will keep vanishing (a bit like Arctic ice). The only thing that can remain is the 'No it's not' hard line. What will it take to break that wall down?
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  30. archiesteel (#177), you said:
    "Irrelevant. We are not debating whether or not the fact that it's currently warmer than the LIA is a good thing or not. We are debating the risks caused by such unprecedented human-made warming, especially with regards to the future. You see, I care about future generations. I suggest you start caring as well."

    I disagree. It is highly relevant that the present is a better time to live than the LIA owing to the higher temperatures. My caring started a long time ago when working to reduce pollution in London (UK). Actions speak louder than words.

    If this thread is about anything it explores the relationship between atmospheric CO2 and climate. I find the arguments of "apiratelooksat50" more persuasive than anything the vocal majority here has offered. I strongly endorse his answers in #175.
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    Moderator Response: Everybody stick to the topic of this thread.
  31. @gallopingcamel: this is getting off-topic, as indicated by the moderator, so I'll try to seque back to CO2 and its lag.

    "It is highly relevant that the present is a better time to live than the LIA owing to the higher temperatures."

    Sure, as long as they remain within natural viability, i.e. the temperature we had before the current warming increase (which started long after the LIA had ended). The fact that we have pumped CO2 in the atmosphere has taken us out of the natural variability zone, and we have yet to see its full extent due to the time it takes for the full effect to take place.

    Again, all the evidence points to the fact that CO2 has warmed the climate as a forcing, not a feedback, and thus the "lag" issue is a red herring.

    "My caring started a long time ago when working to reduce pollution in London (UK). "

    That has nothing to do with CO2 and the greenhouse effect.

    "If this thread is about anything it explores the relationship between atmospheric CO2 and climate."

    Actually, this thread is about how the CO2 lag in paleoclimatology is irrelevant to the current warming trend, where CO2 is a forcing rather than a feedback.

    "I find the arguments of "apiratelooksat50" more persuasive than anything the vocal majority here has offered."

    That's because you agree with his opinion .That doesn't make for strong science...

    "I strongly endorse his answers in #175."

    Again, that a politcal agreement, not a scientific one, since he made at least two factual errors in his post.

    I think you've made your case. At this point, all you seem intent on doing is repeating the same thing over and over, which is a hallmark of contrarians on this site. (sigh)
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  32. Re: muoncounter (179)

    You're right, that one's usually my shtick. This Skeptical Science update of the ice core/Mauna Loa data is pretty compelling, too:


    For over 400,000 years atmospheric CO2 has never been over 300 PPM...until now

    The Yooper
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  33. 175, apiratelooksat50,

    So all of your arguments devolve into one thing -- that the mechanisms as described are correct, but the quantifications are either unknown or unknowable, and therefore everything can be ignored.

    Let's get more to the point. You dodged my last question completely. Given the understanding of how CO2 has affected both temperatures and the entrance and exit processes for glacial periods in the past, regardless of degree:

    The "temperature lags CO2" argument against CO2 induced climate change is an invalid one.

    That is:

    (a) CO2 has lagged the initial change in temperature in the past, but ultimately is still a major factor in pushing temperatures further up or down -- the appearance that CO2 lags temperature is an illusion due to the fact that the initial forcing is from a change in albedo, and puts CO2 increases "behind the curve".

    (b) Increases in CO2 without the same historical initial forcings and sources (i.e. CO2 as a result of increased temperatures, versus CO2 as a result of the burning of fossil fuels) can be expected to have similar effects, regardless of the fact that in this case CO2 is not rising as a result of rising temperature.

    Do you agree?
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  34. Daniel Bailey @ 182. If CO2 levels are a major force force in global temperature increases, and we have this sharp increase, then the we should see a similar increase in temperature. Can you overlay that graph, as well?
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  35. Sphaerica @ 183.
    "So all of your arguments devolve into one thing -- that the mechanisms as described are correct, but the quantifications are either unknown or unknowable, and therefore everything can be ignored."

    That is a broad stroke of the brush, but in an attempt at brevity: I have other points. Mechanisms are mostly correct, but the quantifications are not verifiable at this point. Nothing should be ignored, but instead should be considered in reality and not in gross projections of worst-case scenarios.

    "Let's get more to the point. You dodged my last question completely. Given the understanding of how CO2 has affected both temperatures and the entrance and exit processes for glacial periods in the past, regardless of degree:

    The "temperature lags CO2" argument against CO2 induced climate change is an invalid one."

    What!?!? Isn't this whole thread about orbital forcings and didn't we agree on the abilitiy of orbital cycles to initiate both warming and cooling phases?

    "That is:

    (a) CO2 has lagged the initial change in temperature in the past, but ultimately is still a major factor in pushing temperatures further up or down -- the appearance that CO2 lags temperature is an illusion due to the fact that the initial forcing is from a change in albedo, and puts CO2 increases "behind the curve"."

    CO2 is a factor, but the major title is still disputed. I can trot out as many peer reviewed papers as can you that differ with each other. And, did you really use the word illusion? We really are getting into magical realms, now.

    "(b) Increases in CO2 without the same historical initial forcings and sources (i.e. CO2 as a result of increased temperatures, versus CO2 as a result of the burning of fossil fuels) can be expected to have similar effects, regardless of the fact that in this case CO2 is not rising as a result of rising temperature."

    Of, course. CO2 is CO2. Whatever effects it has are going to be the same regardless of the source. It's the magnitude of these effects that are in legitimate question.

    "Do you agree?"
    See above.
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  36. @apiratelooksat50: "If CO2 levels are a major force force in global temperature increases, and we have this sharp increase, then the we should see a similar increase in temperature."

    CO2 is not the only factor in global temperatures. It's naive to think there would be a 1:1 increase, and no one (except you, it seems) thinks this is what happening. It would appear you are setting up a strawman.

    This graph, posted in another article, does however show a pretty good relationship between CO2 and temperature:



    "Nothing should be ignored, but instead should be considered in reality and not in gross projections of worst-case scenarios."

    Hope for the best, prepare for the worst is the better survival strategy.

    I'll add that most projections are in fact conservatives, and that apathy is a much bigger threat than alarmism right now.

    "What!?!? Isn't this whole thread about orbital forcings and didn't we agree on the abilitiy of orbital cycles to initiate both warming and cooling phases?"

    Sure, but orbital forcings aren't responsible for the current warming phase. That is pretty easy to prove, considering we have a pretty good grasp of the Earth's current orbital parameters.

    "CO2 is a factor, but the major title is still disputed."

    Not really.

    "I can trot out as many peer reviewed papers as can you that differ with each other."

    97% of publishing Climate Scientists support the idea of CO2 being the major driver of the current temperature increase. That's pretty far away from 50-50...

    "It's the magnitude of these effects that are in legitimate question."

    It's not really in question. Just about the only "scientists" contesting this are financed by conservative think tanks, themselves bankrolled by the like of David Koch and his ilk.

    Seriously, there's not much to debate. Deniers and contrarians have failed time and time again to provide scientific evidence to support their challenge - and don't make any mistakes about it, the burden of proof is on them to show that the established science is wrong, not the other way around.
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  37. #184: "Can you overlay that graph"

    Already done, most recently here. If you would look at and read and learn from other threads, you would see that your 'objections' have answers.

    All except for that untouchable bottom line 'no it's not'. Perhaps you should answer the question: What caused you to become so convinced that you are correct? What allows you to disregard mountains of evidence and cling to your pre-conceived mindset?

    #185: "Nothing should be ignored, but instead should be considered in reality ... "

    Ahh, now we bring in the reinforcements: solar magnetic field, cosmic rays, blocking, solar UV and what not? 'ABC': anything but CO2!

    Archie beat me to it. Continuing to chase those other strawmen is off topic for this thread.
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  38. Re: apiratelooksat50 (184)
    "If CO2 levels are a major force force in global temperature increases, and we have this sharp increase, then the we should see a similar increase in temperature."
    Strawman argument. Lest I must repeat myself, this was all discussed further upthread.
    "Can you overlay that graph, as well?"
    archiesteel at 186 and muoncounter at 187 have more than fulfilled this request of yours.

    The Yooper
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  39. 185, apiratelooksat50,

    So, at the end, you come out with the same old, tired, wishy-washy nonsense. You agree with the logic, but there are "uncertainties" and things we can't quantify or know and "It's the magnitude of these effects that are in legitimate question."

    No, they're not. At this point in time, multiple lines of evidence, from paleohistory to simple physics to GCMs all project climate sensitivity at between 2˚C and 4˚C per doubling, with somewhere around 3˚C being the best guess. So many lines of evidence converge on that point, as a matter of fact, that its nearly a certainty, and if there's any error in the estimate, it's in being too low.

    Still, at the end, you're position is simply that of the tired robots who are ideologically motivated and so can't be swayed by facts, because the facts can always be interpreted in a pleasing way to meet your wishes. And you've wasted everybody's time.

    Some simple irrefutable facts:

    1) If we address the problem now, it will be cheap. If we don't both the suffering and the costs of climate change will be enormous.

    2) Many of the solutions are in the ecological, strategic and economic interests of all parties anyway, completely separate from climate change issues.

    3) There is immense inertia in the system. We have already dialed the planet's thermostat way, way up. Even if we found a way to completely stop burning fossil fuels today, the damage would be immense. The planet's temperature would continue to rise for some time. So your strategy of delay and deny and refute and vacillate and "let's just wait and see, shall we?" is going to have enormous, horrific repercussions. If we don't get things under control for 20 or 30 years, the price is going to be very, very steep.

    From the very beginning, I found your evolving tone of rational, mild resistance to be disingenuous. It set off all sorts of alarms in my denial detectors. I'm angry with myself for having held out hope, but on the other hand I'm certain that any number of lurkers have read our exchanges, and learned from them.
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    Moderator Response: Additional comments on topics that are specifically addressed by other threads must be on those threads. I mean apiratelooksat50 and everybody else. Please.
  40. Archiesteel @ 186
    "It's not really in question. Just about the only "scientists" contesting this are financed by conservative think tanks, themselves bankrolled by the like of David Koch and his ilk."

    By this logic, "scientists" financed by liberal think tanks should be ignored as well.
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    Moderator Response: Okay, fair enough. Now everybody please back off the politics.
  41. archiesteel (#186),
    Trotting out that tired old graph shows that you don't understand what I explained in #154.

    You misunderstood (deliberately?) "apiratelooksat50s" comment (#184). He was challenging you to match the CO2 curve to temperature over an extended period of time and that simply can't be done. The best you can hope for is a match over a few decades (e.g. 1975 to 2000) but there will be other periods where the correlation is in anti-phase (e.g 1934 to 1975) at least in the arctic:
    http://www.skepticalscience.com/twice-as-much-canada.html
    http://diggingintheclay.files.wordpress.com/2010/12/coastal-average.png

    In an effort to find common ground, I support DB's opinion that the funding issue is a red herring.
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    Moderator Response: {Daniel Bailey] I made no such claim about funding. But while I'm here, let's address your misunderstanding of archiesteel's graph. You are simply incorrect that a match cannot be done over a space longer than a few decades (a thorough reading of this post over at RC is called for), as archiesteel's graph covers a 160-year period. If you want still longer, than how about this (note the zero year is 1950):
  42. Sphaerica @ 189:
    "So, at the end, you come out with the same old, tired, wishy-washy nonsense. You agree with the logic, but there are "uncertainties" and things we can't quantify or know and "It's the magnitude of these effects that are in legitimate question.""

    We agree on some of the more basic mechanics and science of climate. Absolutley there are uncertainties and unknowns. Read the pro-AGW papers yourself and note the use of "uncertain" words like may, possible, potential, suggest, etc...

    Read the twisted logic in the last paragraph that started this thread. It says that CO2 did not initiate the shifts toward interglacials the past 400,000 years, but current climate change is driven by GHG's. It then has the audacity to say the conclusion was not based on analysis of past climate change.

    I'm a peacemaker by nature, and I realize that discussing climate change and it's mechanics are akin to discussing evolution vs. creationism. (FWIW I firmly believe in evolution). We will probably never agree with the other side, but serious, civil scientific discussion is always enjoyable. Only the march of time will decide who the victor in this debate is.
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    Moderator Response: [Daniel Bailey] You misquote Anne-Marie's paragraph:
    "To understand current climate change, scientists have looked at many factors, such as volcanic activity and solar variability, and concluded that CO2 and other greenhouse gases are the most likely factor driving current climate change."
    This issue has been examined thoroughly. Per the National Academies, global warming is an accepted fact and that we are causing it is a greater than 90% likelihood. The reason that past climate change is not a useful comp for what is empirically, measurably occurring today is that at no demonstrable point in the paleo record has CO2 ever increased in the atmosphere by such a large amount in such a short period of time in the absence of other causative forcings and feedbacks (the rate is the thing). If you don't understand the post and the material it links to, don't mischaracterize with terms like "twisted logic" or "audacity". Similarly, if you do understand it but disagree, do so respectfully. And provide links to peer-reviewed, published material that supports your disagreement. All else is hand-waving.
  43. @gallopingcamel: "Trotting out that tired old graph shows that you don't understand what I explained in #154"

    It's not a tired old graph, and it shows exactly what apiratelooksat50 asked about: a correlation between CO2 and temperature.

    The "red herring" is your artificial requirement that CO2 and temperature must *always* correlate. That's simply not true, as aerosols and other forcings (such as orbital forcings) can also affect temperatures.

    What you and apiratelooksat50 have failed to demonstrate is how the current warming isn't linked to CO2, despite the mountain of evidence suggesting it is. Until you bring that evidence, you have no argument.

    Oh, and I wasn't briging up the funding issue, I simply stated in a colorful way that only a very small minority of climate scientists support your position, and that many of them appear to be scientists-for-hire given their past employers. I do agree that it's off-topic, however, and won't mention it any further in this thread.
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  44. apiratelooksat50

    To put it very simply: looking at the causes of past climate change will not tell you much about the causes of current climate change. To understand current climate change, you have to look at the different factors which we know have an impact on global climate. Scientists have done that, and concluded that CO2 and other greenhouse gases are the most likely cause of current warming, while other factors such as solar variability, the Milankovitch cycles, internal variability and volcanic activity are very unlikely to be the cause of current warming. It's not twisted logic, it's the conclusion reached by thousands of climate scientists based on evidence. Because one factor was responsible for warming in the past doesn't mean that factor is responsible for current warming.

    I have already asked you to tell me which mechanism is responsible for current warming, if not CO2 and other greenhouse gases, and you failed to answer me. So I'm going to ask you again:

    1) Which factor is responsible for current warming, and what data do you base this assertion on? Can warming caused by this factor explain other observations, such as nights warming faster than days and stratospheric cooling? You seem to think that orbital changes are responsible for current warming - can you find me a single scientific paper that shows it?

    2) Why would an increase in CO2, a gaz which absorbs and re-emits infrared radiation, not have an impact on temperatures? Do you have evidence, as published in the scientific literature, that the theory of anthropogenic climate change is fundamentally flawed?
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  45. archiesteel (#193),
    Enough of the straw man approach. It may surprise you when I assert that CO2 "always" correlates with climate as it affects the energy balance through the well understood process of capturing long wavelength radiation.

    Where we diverge is in the magnitude of the effect in relation to other things that influence climate, such as water vapor, clouds, aerosols, cosmic rays etc.. What should be red flags to those of you who are so sure that CO2 is the magic bullet of climate change is the inability of the modelers to explain past climate change and their lack of predictive powers.

    As "apiratelooksat50" and others including myself have pointed out many times, the uncertainties are great. We are trying to measure changes of a few tenths of a degree in measurements that oscillate over very wide ranges from night to day and summer to winter.

    What we know about climate change is vastly exceeded by what we don't know. Those who express certainty that CO2 is driving modern climate come across as zealots rather than scientists.
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  46. Anne-Marie Blackburn (#194), you said:

    "Do you have evidence, as published in the scientific literature, that the theory of anthropogenic climate change is fundamentally flawed?"

    You have it backwards. It is up to the proponents of AGW to make better case for the hypothesis.
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  47. gallopingcamel

    The case has been made. It is accepted by the majority of climate scientists and by scientific bodies around the world, and is supported by a huge body of evidence coming from many disciplines. Up to you now to show where it's gone wrong if you think it has, and substantiate it with data analysis, not hypothetical musings.
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  48. gallopingcamel,

    Those who express certainty that the scientific community hasn't considered [x], [y], or [z] come across as zealots rather than skeptics.
    0 0
  49. gallopingcamel wrote : "What we know about climate change is vastly exceeded by what we don't know. Those who express certainty that CO2 is driving modern climate come across as zealots rather than scientists."


    'What we know about cosmogony is vastly exceeded by what we don't know. Those who express certainty about the origins of the universe come across as zealots rather than scientists.'
    Help - we can't know everything, let's give up or call those smarty scientists zealots for being so clever and all, pretending they know more than the rest of us.

    By the way, previously you went on at length about what you are doing to convince yourself of AGW - if such an end result is possible with you. What similar work have you done to convince yourself of the merits of cosmogony and evolution ?
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  50. GC @197,

    "You have it backwards. It is up to the proponents of AGW to make better case for the hypothesis."

    No, you have it backwards GC. In science one can prove nothing; it is not mathematics. One can, however, refute or disprove something. The scientific case for the theory of AGW has already been made-- it has evolved from the knowledge and understanding integrated over more than 100 years and across multiple disciplines.

    Now if you wish to refute it or disprove the theory of AGW, then the onus is on you to present credible, coherent and reproducible scientific evidence to the contrary.

    They have been trying to do so for over 100 years now (Spencer Weart's book provides an excellent overview) and so far all attempts to do so have failed. Those opposing the theory of evolution have run into the same problem again and again.

    The fact that in the past global SAT lead CO2 is well understood, is entirely consistent with the science and also demonstrates that CO2 is in fact an important regulator of global SAT (as was also recently demonstrated by Lacis et al. 2010). Additionally, that observation does not, however, preclude CO2 from being a major climate driver when we rapidly increase it to its highest levels in potentially 15 million years.

    Even Christy, Lindzen and Spencer agree that doubling CO2 will warm the planet-- that is increasing CO2 will increase global SATs. However, believe (rather wishfully some would argue) that climate sensitivity is low. But that is a subject for another thread.

    In closing GC, if you or a graduate student or scientist can disprove the theory of AGW, then I see a Nobel in your future.
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