Cycles, projections, and other lingo

So I was at work today, and with all the bad weather he had plenty of time to shout at the boss and another co-worker about global warming.  It was a good 2-on-1 handicap match. “Talking” debates are not really my thing since no opportunities exist to check claims, reference sources, show graphs, etc that you could do in online/text correspondence, and so basically anything goes.  Even totally wrong claims like “Volcanoes spit out more pollution than humans do.”

 The boss and the co-worker were very skeptical.  I’m not sure how scientific our exchange was– they spent most of the time trying to convince me I should be very cautious in trusting the general scientific community, and I spent most of the time telling them that they should trust physics, but no one budged.  They’re intelligent group of folk (one trained in biology) but not really familiar with the climate science literature, so I tried to avoid ideas like “radiative forcings,” “water vapor feedback,” “stratospheric cooling,” and other concepts.  So we didn’t really discuss “how CO2 influences climate” or even radiative feedbacks, and it probably was worthwhile as a philosophy of science talk if anything.

Still, I was troubled by a lot of misconceptions they had with terminology, and the basic way in which attribution of warming is (and is not) carried out.  This is something that I’ve run into with other “dinner table” quality discussions.  This post will be nothing interesting to those who have followed the issues, although many of us may lack experience talking to general people like our friends or co-workers who have not engaged in the back and forths of the “debate” or have studied documents by IPCC, National Academies, etc.  Some concepts are:

1) Cycles: This follows the traditional “we’re in a cycle” line of thought.  The justification was essentially that warmer and colder times happened before, and the co-worker reminded me of the ice core bubbles showing ups and downs in the past.  I’m pretty sure she was talking about Milankovitch variations over the last million years.  The term “cycles” in thrown around very loosely in these kind of discussions.  So a few pointers

  • The term “cycle” has a precise statistical meaning.  Just because climate changed before doesn’t mean “it’s a cycle.”  The sun has a very clear cycle of roughly 11 years corresponding to changes in solar output, day-night variations are a cycle, there is a seasonal cycle, but in fact true cycles which affect the climate of the planet are not very common.  Milankovitch are probably quasi-cyclical, but also not relevant for modern global change.  Long-term changes in plate tectonics, mountain uplift, and other geologic controls are not cycles.
  • Cycles are real physical phenomena, and thus if they change the Earth’s climate they did it in some real way, which needs to be defined.  Seasons for instance are caused by the tilt of the Earth and the motion around the sun, while day-night changes are caused by the Earth’s rotation.  Just saying “it’s a cycle” is not very useful: does this cycle happen to deliver the Earth more solar output, what kind of fingerprints should it leave behind, how long is the cycle, etc?
  • Humans are a new part of the equation.  Life can influence the climate.  Plants and other organisms took an entire deoxygenerated atmsophere and put oxygen into it making it suitable for the life we know today (which by the way is not a cycle).  There should be nothing mystical about humans being able to change the climate, particularly as it’s easy to monitor changes in atmospheric chemistry through  emissions.
  • Timescale matters: Milankovitch cycles influence climate on timescales of thousands to hundreds of thousands of years.  Day-night cycles influence people on timescales of many hours, while seasonal variations influence people on timescales of months. 
  • Forcings on climate need to be added, not replaced.  Different things can change the climate.  If multiple things are changing, then you need to add them up, not pick which ones you like.  If the sun is going up and CO2 is going up, you can’t just say “it’s the sun” because you like “natural” stuff or you don’t like humans or you like big yellow balls of fire, or whatever else.  The influence of CO2 is very well defined and can be calculated with high accuracy and thus no physical justification exists for ignoring it in modern or future global change

2) Self-Correcting mechansisms: My boss was convinced that even if it got warmer, the climate would fix itself.  He was not necessarily referring to what some specialists would call “negative feedback” (some people invoke some cloud-albedo mechanism), and actually he bewildered me with some radical plate tectonics idea about warmer temperatures meaning more volcanic eruptions and a return to today’s climate (although that’s not actually what would happen).   He told me an asteroid could hit the Earth, or whatever else that was beyond prediction.  So, some points

  • Asteroid impacts or more volcanic eruptions are not “self-correcting mechanisms.”  They aren’t cycles either.  They are completely random events, and various hypothetical examples could push the climate further or away from the current warming trajectory.  Relying on them for prediction is obviously kind of strange.  The Earth actually doesn’t care what the climate is, and so there is no tendency for it to be the pre-industrial climate.  The concern is us, and current ecological structures.
  • Again, timescale matters: The Earth has gone from climates without ice sheets and alligators roaming around in swamps in the present day arctic circle, and there have been climates where Earth was covered (or nearly covered)  in ice.  Some might call, say, the silicate weathering thermostat hypothesis to be a “self-correcting mechanism” although this is important on hundreds of thousands and millions of year scales.  A key observation is that the climate can clearly change and stay in a new state on timescales which are far longer than we need to be worried about, and extra CO2 can influence climate for thousands of years after it is released.  Because the surface boundary conditions and ice sheets will change, there’s also no reason why such “self-correcting mechanisms” should bring us back to this climate or anything which humans will be adapted nicely to. 
  • The paleoclimatic record, and even observations in the 20th century (like after the Pinatubo eruption) are incompatible with a very low sensitivity to change, and the geologic record provides a treasure chest of different climates.  Thus there is no basis for claims that further heating will “correct itself” or bring us back to a state like today.

3) Projections vs. Predictions: As noted above, relying on asteroid impacts or alien invasions or worldwide viruses to knock out predictions of future global change is not very worthwhile, and it’s also meaningless to discount current projections because those things “could happen.” 

The trajectory of future global change depends on climate sensitivity, but also on how human actions evolve in the future; the second one is purely up to us.  For instance, whether we decide to stop all emissions today, or steady out CO2 slowly, or do nothing for 50 years and then stabilize are all different scenarios that have different repercussions for climate. 

fig-10-4

Therefore projection of future climate carries with it the assumption of various socio-economic scenarios (outlined in detail by SRES), something reasonable probably falls between the yellow line and the red line up there.  This depends on how humans decide to clean up their act, or if we choose to do so at all. This is a different kind of uncertainty than how the climate actually responds to a given change in atmsopheric chemistry, which is why “a doubling of CO2″ is often used as a better metric than “by 2100″ or other date. As described in this paper emissions continue to grow from economic expansion and use.  The world also doesn’t end in 2100, so choosing to do nothing will result in the high end of the above projections without stabilization at the turn of the next century, something a bit misleading with the green and purple line.

4) Attribution:

  • How the past record ties into it: How the climate has changed before provides invaluable insight into how sensitive the system is to change, for testing our understanding of what forcing agents matters and on what timescales, etc.  However, it is not very meaningful for the attribution of 20th century warming or projections of future global change.  Humans are a new dimension in global climate, and thus our influence has to be evaluated accordingly.  Just because forest fires occurred naturally in the past doesn’t mean an arson can’t start one today.  Murderers don’t get off on the claim that “people always die anyway” and so humans shouldn’t get off the suspect list just because of how climate changed before, or because our measurements only go back a limited amount of time.
  • Assessing spatio-temporal patterns of change: Attribution of climate change to a particular cause(s) is not a process-of-elimination approach.  We don’t pick out of a hat, nor do we take a vote.  Formal attribution doesn’t even depend on our ability to simulate the 20th century with models of greenhouse gas + natural forcing, and not natural forcings alone, and can even be accomplished when subtracting global mean trends (although this is interesting to stare at).   Usually formal attribution involves comparing spatio-temporal patterns to a set of forcings (through models or theory) and allowing the amplitudes of various forcings to vary.  Natural variations fail to account for the observed trends even with overinflated responses, something robust to various models, methods, or assumptions about internal variability.  A key point is that no physically plausible way exists to systematically increase carbon dioxide in the air and not expect a warmer world.
  • Assessment of future global change is not based on the increase of temperature over the last century. 

The global mean temperature change is nearly 1 C over the last century.

nhshgl

 

This is not why we expect temperature to continue to rise…it has more to do with the fact that  we expect greenhouse gases to continue to rise, and we know that the climate still has to “catch up to us” so heating in the pipeline will be realized.  Even transient forcings like solar output going down or volcanic eruptions will eventually be outdone by the much longer-lived greenhouse gas influence.  

5) Sources

  • Science is done by scientists, so reading what scientists have to say about the subject is probably a good idea, at least before opining on the topic.  Many people just don’t care all that much about the science (just as I know nothing about black holes or organic chemistry) and for such people the media or quick wikipedia searches will suffice, but then those people have to at least realize that they are not in a place to make judgment about the quality of research, just as I am in no posittion to disagree with an astrophysicist about black holes.  It makes no sense.  If you think  the scientists are bending the truth after a good amount of research is conducted, it’s your perogative (although much of the underlying data and physics can be validated for people really interested), but for those really interested there’s very good reports from the IPCC, from the recent Copenhagen climate conference as well as various pieces by the National Academies of Science, USCCP, as well as the hundreds of peer-reviewed documents available in journals, “.edu” resources, etc.  The studies and data coming out analyzing climate change are done by research groups at universities, organizations like NASA, NOAA, etc.  There is thus no need to rely on Al Gore (or Rush Limbaugh!!) for information, and such spokespeople do not directly contribute to the research in the field.  Some blogs, random “.com” websites, etc may be good, although you probably won’t be able to tell the difference if you don’t familiarize yourself with the original research first.
  • I think many people are unaware of the breadth and depth of the scientific literature on climate change, and the overwhelming amount of research conducted by the scientific community.   The first estimates of the influence of CO2 change was done in 1896, and the field has evolved tremendouly over the last century, with many of the key aspects known well before any of the researchers today were born.   This is not one of those things which is open to public preference or opinion, and it involves a great deal of complexities which cannot be understood through quick google searches. 

Update– July 8: I’ve messed around with the wording of things for clarity.

About these ads

46 responses to “Cycles, projections, and other lingo

  1. Hi Chris,

    As a skeptic, I share your frustration equally, and as a genuine skeptic, and someone who does care about the environment, I am ready any day of the week to have my opinion sway back to believing in / trusting the consensus / IPCC position. Further, I know exactly what would sway me: dialogue, and constructive debate with the skeptics, in particular those skeptics of the ilk of Lindzen, Christy, and, although he refuses the label “skeptic”, Pielke Sr. The present debate between RealClimate & Pielke is interesting, but the ad hominems coming from the RealClimate side greatly increase skepticism, and bolster Pielke’s standing in the eyes of lay people. It’s true that Pielke has been a little shrill, but that doesn’t affect his argument. It also seems to me that Pielke’s basic point, that RC has overstated things, has not been refuted honestly, and only further bolsters Pielke’s standing. These are the pieces of the puzzle that the lay public can always understand: We can always see an ad hominem attack for what it is (I refer to the attacks by commenters at RealClimate, which were not removed by the editors). In most cases, straw men arguments can also be seen for what they are. And then an argument, “we don’t have to answer that ’cause it wasn’t peer-reviewed” always also increases the lay public’s skepticism. No one takes that response seriously, and again, skepticism can only increase. Finally, dialogue with McIntyre & Mann would greatly help move this debate forward, and these refusals to talk to McIntyre because he’s a former mineral consultant, or because he’s allegedly not a nice person on his blog, or because he keeps asking people for their data & people resent giving it to him, further increasing skepticism.

    I too want to see this debate resolved, but I see everything as being polarised, and a depolarisation/resolution cannot occur until there is simple, honest, civil dialogue.

    Best regards,
    Alex

    Response– I’ve only reviewed the RC-Pielke exhange briefly, which is just another instance of cherry-picking of a couple years of data. I don’t understand what serious rebuttal is supposed to be presented here, nor did I see the ad homs to which you refer (at least by the RC authors, hostile user comments occur on any blog, including my own…do you read WUWT?), and it is Pielke who made accusations against RC in this case. In fact gavin specifically disagreed with a commenter calling Pielke a “liar.” Further, RC only summarized the findings of the Copenhagen synthesis report; Pielke misunderstands the conclusions about certain *trends* occurring faster than projections.

    I don’t believe that repeating the same things over and over (i.e., look at trends, not a couple of data points) is healthy anymore to the “debate” or “dialogue” or whatever you feel is going to help the science. Much of it is stuff you pick up in 100-level work. Continuing to debate the quality of a paper that is well over a decade old is also probably not going to forward the science either. I’m not sure if you’re looking for people to have a productive dialogue or to score points in debate. As dismissive as it may sound to the general public, if scientists want new work to be taken serious, they need to publish it and have it stand up to expert scrutiny. If I want to put an original argument on my blog, I might hope some expert comes by and reads it and considers it, but I should not require nor expect this to happen. That is standard protocol in any field of study, so if the public doesn’t like climate science in that particular respect, it is only because it gets more public attention. If refereed results are worth paying attention to then it will leak into the blogosphere and capture public attention very easy.– chris

    • Alex,

      The snarky comments directed at those who post in unfriendly forums do seem to happen everywhere, and on both sides. Cherry picking data also happens on both sides. A perfect example off the top of my head is Santer et al 2008 where they chose 1999 as the end point of their data run. Despite nearly a decade going by, they chose the 1998-99 El Nino superspike as their end point.

      The real difference I see in the research is the openness. The “Consensus” seems to jealously guard their methods, making it really tough to duplicate their findings. Rahmstorf et al 2007 used a smoothing method that was kept so secret that Rahmstorf himself flat out lied about using padding to throw people off the trail.

      If the goal is to educate people, then educate people. Let them see what you are working on. Let anyone who wants to duplicate the results so they can see for themselves. That is what I’d like to see change. As for the cessation of people aping Gore or Limbaugh, or all forum posters being cordial and open, or wishing all could take the time to educate themselves before offering up an opinion, I think that is a bridge too far.

      -Bryan

      • Gavin's Pussycat

        > Rahmstorf et al 2007 used a smoothing method that was kept so secret that
        > Rahmstorf himself flat out lied about using padding to throw people off the trail.

        Bryan, remember that libel is only actionable if you publish your full name… the “Rahmstorf smoothing method” is documented in one of Rahmstorf’s references to the article, and the Matlab code available from its author Aslak Grinsted for the price of one email.

        You would know that if you had any curiosity or interest in the truth. Yuck, you denialist fraudtors [compulsive hand washing]

  2. Your second bullet on cycles and attribution tie together. You tend to say, not explained by anything other than man-made warming, when the argument is that there is some other unknown forces at work. The forces are unknown, and the belief is that there is something other than man-made CO2 at work. That the believer doesn’t know this force doesn’t mean it doesn’t exist.

  3. Ian Forrester

    Bryan, have you even read Santer et al (2008)? If you had you would see that your comment “cherry picking data also happens on both sides. A perfect example off the top of my head is Santer et al 2008 where they chose 1999 as the end point of their data run” Please read the paper and tell us why it is not an example of cherry picking.

    Here is a hint… quote from the paper “These so-called twentieth-century (20CEN) simulations are the most appropriate runs for direct comparison
    with satellite and radiosonde data…..Since most of the 20CEN experiments end in 1999, our trend comparisons primarily cover the 252-month period from January 1979 to December 1999″ Please explain why this is “cherry picking.”

    No wonder scientists refuse to call you people “skeptics” you cut and past from denier sites without even bothering to read the paper you are trying to shred.

    • Ian,

      RSS data does not end in 1999. UAH data does not end in 1999. Radiosonde data does not end in 1999. Douglass et al 2007, the primary reason for this paper, does not end in 1999. Santer et al 2008 doesn’t even try to hide it. They come straight out and state in the paper they’ve got data through December of 2007, yet they refuse to include it. Instead they chose to end their evaluation at the 1998-99 El Nino.

      The bit about “twentieth-century simulations” may be the weakest excuse for cherry picking that I’ve ever read. Do you really believe that not one of the 17 authors could think of any climate models whose predictions extended beyond 1999? I don’t. I think their feeble attempt to justify the date is hilarious. Cherry picking doesn’t get much more blatant than Santer et al 2008.

      -Bryan

      Response– It wasn’t cherry-picking. For one thing, they were assessing the work of Douglass et al. Why not complain about their selected time period? Even the Douglass paper notes many model studies end with that year (1999), and strangely enough, Douglass et al. compare two slightly different time periods with models and observations (which isn’t a huge deal, but probably not appropriate). Santer et al. specifically note that the time of maximum overlap between obs and models here is up until 1999, so that’s what they did. Many emission datasets have not yet been extended to the last several years. Just ranting isn’t going to change reality.– chris

      • If Santer et al had picked 2004 as an end point, just as Douglass et al did, you’d have a point. Additionally, Per Gavin, the model runs Santer et al used were from IPCC AR4, which had a cut-off date of 2004, not 1999.

        Santer and company are not stupid people. They knew what they were doing.

        “Estimates of the linear trend are sensitive to points at the
        start or end of the data set. … For example, if we considered tropospheric data over 1979 through 1998, because of the unusual warmth in 1998 … the calculated trend may be an overestimate of the true underlying trend.”

        p.132 in Appendix A of the CCSP-SAP-1.1 report, authored by T.M.L. Wigley, J.R. Lanzante, and B.D. Santer.

  4. Ian Forrester

    Bryan, calm down and read the paper. You deniers are so incapable of understanding even simple explanations in scientific papers. You are always looking for ulterior motives for simple decisions. Get a life.

    • Ian,

      Perhaps you can shed some light on the ‘simple explanation’ for Santer et al omitting the GISS data. Chris and I agree that Santer et al 2008 was an evaluation of Douglass et al 2007. Douglass used the GISS data. The IPCC also uses the GISS data. Coauthor Gavin works for GISS.

      Being that I believe Santer et al 2008 is a worthless piece of propaganda that was worked backwards to see if they could cherry pick the data to support a preconceived conclusion, omitting GISS makes perfect sense. Even with the ridiculous 1999 end point, using GISS data in the comparisons cause almost everything to fail. They had to throw it out.

      http://www.climateaudit.org/?p=6106

      Given that I am open minded, and recognize your seeming admiration for the integrity of this group, and this paper, please explain how this is not as bad as it looks.

      -Bryan

      • Ian Forrester

        Bryan said: “Given that I am open minded”. What a lught, you then quote an article from climatefraudit, that just shows how “open minded” you are.

        The reason that Santer stopped at 1999 is that is that the majority of models that Douglass compared the observed data to were only run as far as 1999.

        Please read papers before cutting and pasting dishonest statements from denier sites.

        Please read up on the 20CEN simulations then apologize for your stupidity and arrogance. You will find that most stopped in 1999.

  5. Santer et al, has much larger problems than endpoint. They aren’t even providing the data they used.

  6. Just a couple of quick questions to you Bryan and MikeN: Do you have any scientific education? Have you ever conducted research in any field of natural sciences?

  7. Yes and yes, if you include statistical analyses of natural science data.

  8. Ian Forrester

    MikeN, you could have fooled me.

  9. Ian,

    Please read again what I wrote. The question I asked you, with the open minded comment, and the climate audit link, was why did Santer et al omit the GISS data.

    -Bryan

  10. Guys, this discussion was originally meant to highlight general population misconceptions about the logic and language used in climate change discussions, something probably worth additional insight. Although I did contribute a bit, this is not the thread to discuss Santer et al. or other off-topic issues. I think these things have been covered satisfactorily elsewhere, but if not, feel free to find a more relevant thread.

  11. chris:”they spent most of the time trying to convince me I should be very cautious in trusting the general scientific community, and I spent most of the time telling them that they should trust physics, but no one budged.”

    The point I would make here is that people who support the IPCC-centric view of catastrophic climate change don’t just support physics – they also support “modellics”. You can’t get to a catastrophic rate of temperature increase from physics alone, you need to push it through a hyper-complex computer program. There is little debate that CO2 will have a slight warming effect, but a lot of debate over what the feedback from that slight warming will be.

    Ultimately, there really isn’t a good *scientific* reason for accepting models as physics, and a good deal of skepticism of model results is warranted.

    Cheers, :)

    Responses– Well magic fairies don’t cause feedbacks, that involves physics as well. Declining ice reducing surface reflectivity, the Clausius-Clapeyron relation between temperature and saturation vapor pressure, etc is all real, physical phenomena, and it all emerges in realistic models from principles of radiative transfer, fluid dynamics, and other physical laws. Just because CO2 isn’t the only thing going on doesn’t make all the other stuff “fake.” The best constraints on sensitivity also come from the paleoclimate record, which does not support a climate change as small as you’d get from just neutral or negative feedbacks.– chris

    • shawnhet: Ironically, the only reason for the ‘hypercomplex’ models, is people who deny the elementary physics.

      The original work on how much warming (4 C) could be expected from doubled CO2 was done by hand (Arrhenius, 1896). For all the vast increase in computational capability, and complexity of models, that answer still stands as a fair number.

      It stands because the basic processes are simple. Take the law of conservation of energy. Put more of a greenhouse gas into your atmosphere. The temperature goes up. Period. Barring magic that even Lindzen doesn’t believe exists, the temperature goes up. The only way to avoid that is to start violating the law of conservation of energy.

      ‘hypercomplex’ models aren’t about trying to establish the basic business about the temperature change. They’re driven by having to establish ‘no there isn’t a magic fairy over here _either_. Or to try to approach the more difficult issues about how small areas (like the US — 2% of the globe) are going to feel climate change.

      • Robert,

        I have to disagree strongly here. First of all, models are theory. Models are NOT evidence. I agree that CO2 does cause a warming of the atmosphere. That part is rock solid. It is the feedback multiplier(s) that are very shaky, and are not bearing out with current observations.

        The effect of direct CO2 forcing isn’t enough to get anyone’s knickers in a bunch, so ALL of the models are including various feedback multipliers. The models are being used to blur the lines between what is known, and what somebody thinks could be true. Then the theoretical models are paraded out as evidence.

        There may be no magic fairy, but these models are half fairy tale, and should be regarded as such.

        -Bryan

  12. I’ll have to beg Chris’s indulgence as I go on for a while.

    As a skeptic, I share your frustration equally, and as a genuine skeptic, and someone who does care about the environment, I am ready any day of the week to have my opinion sway back to believing in / trusting the consensus / IPCC position. Further, I know exactly what would sway me: dialogue, and constructive debate with the skeptics, in particular those skeptics of the ilk of Lindzen, Christy, and, although he refuses the label “skeptic”, Pielke Sr. The present debate between RealClimate & Pielke is interesting, but the ad hominems coming from the RealClimate side greatly increase skepticism, and bolster Pielke’s standing in the eyes of lay people.

    I don’t know particularly about Pielke Sr., nor about blog wrangles. Over at my blog, I try to keep things focused on where the science is. That also means I have far fewer commentators. (More are certainly welcome, including or especially folks who disagree with me. But if as, say, some fans of a different blog do, you judge blogs by the number of comments, you won’t like mine much. Judged by content of the comments, I think mine does much better.)

    I’ve disagreed with Pielke Sr., for instance, but in the scientific norm. Tenderhearted readers, unaccustomed to the scientific norm, might have thought I was awfully hard on Roger. (One did say so.) But his own comment was that he appreciated my constructive discussion. This is a cultural issue that I think the general population does not understand. Normal exchanges, for science, about what’s going on, what’s good, or not, are fairly rough and tumble. It may not be the best thing that science is conducted this way, but it is what it is.

    The scientific norm issue is a different matter. The scientific norm is the professional literature, not blog commentary. If you look in to Lindzen and the response in the scientific literature, you’ll find that he’s been met properly (by the standards of science, that is). Namely, he suggested his ‘adaptive iris’ idea. This was based on there being a certain relationship (it had to have a particular sign, and large magnitude) between surface temperatures in the tropics and cloudiness (and, for that matter, particular types of cloud). One paper in the scientific literature doesn’t buy you much. It is the start of the conversation to publish in the literature, not blessing as holy writ. He published, and then got the best possible response — other people used other (better) data sets and observing methods to see if they could get the same answer as he had gotten in his first cut. Unfortunately for his hypothesis, the better data sets erased his effect. Indeed, not only was the magnitude much smaller than he thought, the sign was the opposite of what he thought.

    As far as scientific norms go, he got extremely good treatment. a) he did publish his idea (no ‘conspiracy to suppress’) and b) other people took a serious look at it. It is significant work to take a look at somebody else’s new idea. As a scientist, if you can get others to look at your idea, you have done extremely well. As happens in science, perfectly normally, the initial proposition got rejected by more detailed analysis. Since what was at hand was deriving a relationship between observational quantities, and Lindzen is a theoretician, it’s no great surprise or shame that he didn’t get all the niceties on his data sets right. As usual, devils lay in the details, and the responses were from groups familiar with all the devils laying in those details.

    Where things went problematic was that contrary to proper scientific practice, Lindzen didn’t drop his disproven idea. A bit of ‘is so’ publishing (sorry, it was painful to read his response article and this is all I can say of it) in response to the objections was it. And then much complaining outside the scientific literature about conspiracy, scam, censorship, … To be honest, even his original Iris publication was an example of lenient reviewing. There were problems in his data management in the original paper that even I saw (correctly) would be a problem for his idea — and I’m not a tropical person (polar regions mostly), nor, then, sea surface temperature, nor then or now satellite sensing of clouds. The later publications — in the scientific literature — about his errors confirmed my suspicions, and, unsurprisingly, added a number of problems to what I suspected. But that’s not what you see out on the blog universe.

    You can make some headway over at scholar.google.com. A fair amount of the non-scientific world shows up there, but a fair amount of the scientific world is present.


    always see an ad hominem attack for what it is (I refer to the attacks by commenters at RealClimate, which were not removed by the editors). In most cases, straw men arguments can also be seen for what they are. And then an argument, “we don’t have to answer that ’cause it wasn’t peer-reviewed” always also increases the lay public’s skepticism. No one takes that response seriously, and again, skepticism can only increase.

    I agree that outside the scientific community nobody takes seriously that something didn’t appear in the scientific literature.

    That is a problem with outside the scientific community.

    Doing science is difficult. Over the past 400 years, the modern scientific method has accumulated a lot of knowledge and understanding. Doing science means changing that body of knowledge and understanding. Sometimes that means saying that even though we used to think that something was the case, it really isn’t. Making that argument successfully is hard work. ‘Even’ the easier argument of making an addition is hard work. It’s hard work because other people have to be able to rely very strongly on everything you say in your paper. Everything. A paper of mine (don’t worry about the acronyms) studied HSSW’s contribution to AABW. It’s also possible (or was considered so back then) for ISW to contribute to AABW. Even though my focus was HSSW, I had, for scientific honesty and completeness, to discuss ISW. That paper has been cited as often for its ISW discussion as for the HSSW; and it is only the latter that I was making my original contribution for.

    There are two parts to the scientific publication process important for your comment here. One is, to publish in the professional literature about your idea, you have to examine and explain your idea thoroughly. ‘thoroughly’ turns out to be a lot of work. Second is, you have to research all the relevant aspects of your problem and honestly discuss them. The up side of this is, once you’ve finished a proper scientific paper, it can stand for some time. You might turn out to be wrong about something — because there were different data than you used, or a better technique than you used, or … several things. Being shown wrong by later and much more labor-intensive examinations is fine. But being shown wrong because you failed to do your homework is disaster.

    In contrast is blog posts and comments. The standard there is what I’ll call ‘chatting over a beer’. If you and I sit down and start talking, both of us with something we like to drink, having a relaxed conversation, that’s wildly different than scientific literature. Both of us will say what we think, but there’s no concern about tomorrow you trying to write a paper on which our professional reputations will hang based on what I say. We’re just chatting. I’ll give you my best answer at the time, but if I’ve forgotten something, or the answer is 25.0 instead of 2.50, eh. Just chatting over a beer. Just a blog comment. If someone started writing a scientific paper based on comments in blogs … all kinds of wild things could show up. The earth is flat, hollow, expanding, 6000 years old, and so on. Somebody, somewhere, in the blogosphere has said all such things.

    To do science, we need something much more reliable than ‘anything anybody ever says anywhere’. We even need something better than “well, he’s normally pretty good so even tough he’s never worked on this kind of problem before and doesn’t know how the satellites detect what he’s working with, he _must_ be right anyhow.” That something more is the professional scientific literature.

    Within the world of science (all 20 or so of us), it is an extremely telling, and negative, thing that much of what the general public thinks is the case about science is actually based on things which are said _only_ outside the scientific literature. If the speaker had confidence in his statement, he’d try to publish it in the literature. And, if they were right about the ‘conspiracy’, they should at least have a rejection letter and comments from the editor and reviewers to show. Instead, they talk about the conspiracy, but have no rejection letters (_I’ve_ got rejection letters — they’re normal to trying to do science.)

    But the public perception is quite different. Still, I have to think if someone won’t go in front of his professional peers and stand for what he thinks is scientifically correct, he doesn’t really believe it himself. If his only or major audience is people who don’t know the science thoroughly, I have to figure he thinks that’s the only audience who’ll let him get away with whatever it is he’s saying now. Fine for you and me over a beer. No fine for doing science.

    • Excellent commentary, Robert. I think you’ve hit the nail on the head – Science is a battle and our arena is the peer-reviewed literature. That literature has been carefully constructed and instituted to serve as a venue within which we may progress our respective fields. Blogs and mainstream literature simply don’t offer the institutions we need to vet and verify scientific ideas.

  13. From experience people like to actually see the changes. I can’t understand how people can think all this CO2 doesn’t do anything to the atmosphere and the earth. I guess for some people, when they see emissions going out into the air it just goes away because they can’t see it anymore. After all the endless research scientists do, convincing people and changing things has got to be the most frustrating. In order to convince people with little or no knowledge of the expertice of the scientific data, it may have to be shown in laymans terms. Ex: On the weather channel it will say ozone particulates good or bad, etc. For some that may not be too far fetched! Not that it should be that simplified, but if someone doesn’t follow all the charts and data as a scientist would, or is a non-believer, they may want to actually see a weekly or daily comparison chart (with a starting date such as the industrial revolution) as to what our CO2 levels,etc. are. Some channels show how the earth was when it was very hot, and when we had ice ages. When I see certain instances that happened to create things like temperature change, it makes you have more understanding of the earth. These shows are extremely interesting, to me anyways. Everyone has easy access to their weather, why not show people, (on a regular basis) what the CO2 levels are everyday in their city or country. Maybe— people may understand that they actually do have a contribution in the matter!

    • Carol,

      You’ve got it backwards. The CO2 levels did not “create” things like temperature change. Temperature change created changes in the CO2 level.

      Old research on ice cores was done with equipment that could not date the CO2 levels and temperature changes with enough precision to tell which came first. The best anyone could say was there seemed to be a correlation between the two. It is this research that has been cited by non-scientists, like Al Gore in his movie, as proof of their view.

      The testing equipment has advanced, and can now resolve such things with more precision. Testing on the Vostok Ice Cores has proved that upswings in temperature happened before upswings in CO2. Downturns in temperature also preceded downturns in CO2 levels.

      Shows like the one you mention give people a false understanding of the earth.

      -Bryan

      Response– This has to be a joke. Just stop.– chris

      • Chris,

        You objected to that?!?! I’ll admit to getting out on the edge sometimes, but not with that post.

        [1] Fischer et al (1999) – “Atmospheric CO2 concentrations show a similar increase for all three terminations, connected to a climate-driven net transfer of carbon from the ocean to the atmosphere. The time lag of the rise in CO2 concentrations with respect to temperature change is on the order of 400 to 1000 years during all three glacial-interglacial transitions.”

        [2] Monnin et al (2001) examined the Dome C record, and found CO2 lagging by, on average, 400 years. The initiation of the rise in CO2 lagged the initiation of the rise in temperature by around 800 years.

        [3] Caillon et al (2003) used Argon isotopes to measure temperatures instead of water ice as the two above papers used, and again found CO2 lagging temperature by around 800 years.

        [1] http://www.sciencemag.org/cgi/content/full/283/5408/1712
        [2] http://www.sciencemag.org/cgi/content/full/291/5501/112
        [3] http://www.sciencemag.org/cgi/content/full/299/5613/1728

        Honestly, I expected a response having to do with feedback. I guess I don’t know you as well as I thought I did.

        -Bryan

        Responses– I don’t object to the fact that changes in climate can impact atmospheric chemistry. A warmer world changing ocean upwelling and solubility, biological systems, etc should change atmospheric greenhouse gas levels, and actually that’s something which should probably be self-evident. I do have issues with the intentional misrepresentation of this basic science, just as all the sources above have been misrepresented by so-called “skeptics” to confuse people. For instance, read the conclusion of Caillon et al.

        //”Finally, the situation at Termination III differs from the recent anthropogenic CO2 increase. As recently noted by Kump (38), we
        should distinguish between internal influences (such as the deglacial CO2 increase) and external influences (such as the anthropogenic CO2 increase) on the climate system. Although the recent CO2 increase has clearly been imposed first, as a result of anthropogenic activities, it naturally takes, at Termination III, some time for CO2 to outgas from the ocean once it starts to react to a climate change that is first felt in the atmosphere. The sequence of events during this Termination is fully consistent with CO2 participating
        in the latter 4200 years of the warming. The radiative forcing due to CO2 may serve as an amplifier of initial orbital forcing, which is
        then further amplified by fast atmospheric feedbacks (39) that are also at work for the presentday and future climate.”//

        This was incidentally the paper cited in the Swindle video by Tim Ball and others to prove AGW had been falsified. These lines of manipulation are used by creationists to trick people as well, so yes I am serious, I don’t want it on my site because it is not productive skepticism nor does it address anything Carol said– chris

  14. chris

    :Responses– Well magic fairies don’t cause feedbacks, that involves physics as well. Declining ice reducing surface reflectivity, the Clausius-Clapeyron relation between temperature and saturation vapor pressure, etc is all real, physical phenomena, and it all emerges in realistic models from principles of radiative transfer, fluid dynamics, and other physical laws. Just because CO2 isn’t the only thing going on doesn’t make all the other stuff “fake.” The best constraints on sensitivity also come from the paleoclimate record, which does not support a climate change as small as you’d get from just neutral or negative feedbacks.– chris

    Sure all the stuff you mention is physics, but you can’t just take those physical relationships and put in some initial conditions and come up with some reasonable predictions of the real world. You need models to do this,models that make more or less untested assumptions of how the real world operates. I don’t think the other stuff is fake, there is just a whole lot of ways you can put it together.

    The fact that paleoclimate reconstructions that put the best constraints on sensitivity IYO are all contingent on our having more or less perfect understanding of the forcings. If we don’t understand the forcings in the paleoclimate, then we can’t by definition, diagnose the feedback either. The fact that we have a very difficult time measuring present day feedback, should make us a little

    Further, there is no reason why feedback must stay constant either. For example, if North America is 75% covered in ice, then a 1deg C rise in ave. temperature will have a much greater albedo feedback effect than if NA is 10% covered in ice.

    Robert:

    shawnhet: “Ironically, the only reason for the ‘hypercomplex’ models, is people who deny the elementary physics.

    The original work on how much warming (4 C) could be expected from doubled CO2 was done by hand (Arrhenius, 1896). For all the vast increase in computational capability, and complexity of models, that answer still stands as a fair number.

    It stands because the basic processes are simple. Take the law of conservation of energy. Put more of a greenhouse gas into your atmosphere. The temperature goes up. Period. Barring magic that even Lindzen doesn’t believe exists, the temperature goes up. The only way to avoid that is to start violating the law of conservation of energy.

    ‘hypercomplex’ models aren’t about trying to establish the basic business about the temperature change. They’re driven by having to establish ‘no there isn’t a magic fairy over here _either_. Or to try to approach the more difficult issues about how small areas (like the US — 2% of the globe) are going to feel climate change.

    If one takes the GCMs as gospel, then Arrhenius only arrived at a close number by luck. There are a whole lot of processes operating that he never considered (like feedback).

    If the basic business about is that an increase in CO2 increases temperature, then there is no need for a model and no substantial disagreement either IMO. The issue is, how much warming? One does not have to believe in magic to doubt that the warming for the next 100 years will be substantially more than the last 100 years.

    Cheers, :)

  15. Chris, you wrote, “Guys, this discussion was originally meant to highlight general population misconceptions about the logic and language used in climate change discussions, something probably worth additional insight.”

    And look how quickly it turned into a vent for angry people.

    “Please read up on the 20CEN simulations then apologize for your stupidity and arrogance.”

    This is exactly the stuff that Alex Harvey was discussing. I am a student who got fed up with the bias several years ago and began studying the topic. I have to say that one of the biggest factors that initially pushed me to the skeptical side was the way each side conducted themselves. The ad hom attacks, arrogance, and anger that I find on these blogs makes dialogue impossible. If you are correct, why must you be so hostile about it? Your confidence is apparent in the way you conduct yourself.

    Response– I didn’t say that, another commenter did, and I can’t really control other people’s hostility or patience levels. If you’re a serious student looking to learn the issues and avoid angry bloggers, I would strongly recommend the peer-reviewed literature, academic resources, etc. No matter what blog you go to and what position people take, people get hostile on the internet…it’s life and I don’t control it. People who speak of evolutionary theory get angry at creationists who keep repeating that “evolution violates thermodynamics” but it doesn’t mean they are wrong or not confident. Some people will be more than willing to engage in long discussion (see the good posts by Robert Grumbine), even after the points being raised have been exhausted elsewhere. Then, some other people agree with Thomas Huxley,

    “Life is too short to occupy oneself with the slaying of the slain more than once.”

    – chris

  16. Like where is the global warming? This spring was cool and wet in an area slated for climate induced hot and dry. Its like the AWG crowd set themselves up for failure by crawling so damn far out on a unsupported limb.

    How many people now worldwide have these same thoughts after reading the catastrophic scenarios or watching Al Gore’s frightening movie?

    Todays global temperture is .001 degree of what it was in 1979. http://www.drroyspencer.com/2009/07/june-2009-global-temperature-anomaly-update-000-deg-c/

    Its a beautiful summer day…like yesterday and likely tomorrow.

  17. Chris, “No matter what blog you go to and what position people take, people get hostile on the internet…it’s life and I don’t control it.”

    The difference in professionalism and civility between blogs like RealClimate and ClimateAudit is obvious. And it’s not just the commenters.

    Response– Spare me. RC does its share of knocking people who make nonsensical arguments, and CA does its share of blatant personal attacks on “The Team” with titles like “Is Gavin Schmidt honest?” and digs at Dr. Mann whenever possible. Don’t act like the internet civility is one-sided, because it’s not.

    Now please, let’s get the comments back on track to the discussion as I suggested before, because I really don’t want to delete posts which are far off-topic.– chris

  18. Robert Grumbine said July 7, 2009 @ 7:15 pm:

    part I (peer review):

    I agree that outside the scientific community nobody takes seriously that something didn’t appear in the scientific literature. That is a problem with outside the scientific community.

    Just hold on a minute here, we are talking about scientists who have themselves decided to put aside these hundreds-of-years-old conventions of scientific process in order to advocate for themselves on the internet. If Michael Mann, or Gavin Schmidt, or Stefan Rahmstorf, or Eric Steig wish to bypass the peer-review process to publish whatever they want on the internet, then I have no problem with that, but it looks awfully hypocritical, and not to mention strange, when the same scientists who choose to blog themselves refuse to respond to (and in many cases to even name) rival bloggers (like Stephen McIntyre or Anthony Watts) by arguing that these latter have bypassed the peer-review process. That is the big difference here.

    part II (Lindzen):

    As far as scientific norms go, [Lindzen] got extremely good treatment. a) he did publish his idea (no ‘conspiracy to suppress’) and b) other people took a serious look at it. It is significant work to take a look at somebody else’s new idea. As a scientist, if you can get others to look at your idea, you have done extremely well. As happens in science, perfectly normally, the initial proposition got rejected by more detailed analysis. … Where things went problematic was that contrary to proper scientific practice, Lindzen didn’t drop his disproven idea. A bit of ‘is so’ publishing (sorry, it was painful to read his response article and this is all I can say of it) in response to the objections was it. And then much complaining outside the scientific literature about conspiracy, scam, censorship… To be honest, even his original Iris publication was an example of lenient reviewing. There were problems in his data management in the original paper that even I saw (correctly) would be a problem for his idea — and I’m not a tropical person (polar regions mostly), nor, then, sea surface temperature, nor then or now satellite sensing of clouds. The later publications — in the scientific literature — about his errors confirmed my suspicions, and, unsurprisingly, added a number of problems to what I suspected. But that’s not what you see out on the blog universe.

    I wonder how closely you’ve really looked at this. Have you read the recent Rondanelli & Lindzen 2008, JGR, on the Iris hypothesis? Or the the 11 author review paper of Su et al. 2008 where the whole radiative effect of high altitude clouds seems to be a very open question, even if the Iris hypothesis is deemed to be unlikely. (Rondanelli & Lindzen seem to have a response to Su et al. 2008 in review at JGR.) Or are you aware of the Korean team that is collaborating with Lindzen’s MIT team on the same issue? And what of the role of Professor Chou, the Chou (1994) which actually suggested the original Iris hypothesis? Do you see there the input of a Professor Ho? All of this detail gets lost in the general demonisation of Richard Lindzen by the left. The fact is there is no genuine consensus, I am sure of that, and there never has been, such that Lindzen has retained to this day a number of very senior, but quiet, defenders of the theory (and I haven’t of course even mentioned the Spencer/Braswell 2007 GRL paper that supports Iris). Frankly, I think you’ll find that truth be told, these recently very casual, dismissive responses from Lindzen come less from disregard of scientific process and more from his unwillingness to ‘steal the thunder’ of his younger colleagues. So I fail to understand at all how you can say it is ‘proper scientific practice’ just to sort of roll over and die once your idea is said by the IPCC to be ‘disproven’… That’s not how science works at all. One gives up when one no longer believes one’s position, or when one has run out of energy to fight it any longer. Clearly, Lindzen is quite right to continue.

    So much for Iris, which is beside the point anyway — because Lindzen’s recent presentations at WUWT and Heartland have nothing to do with the Iris hypothesis, as he stated very clearly. In fact, he specifically referred the reader back to Chou & Lindzen (2005), which was of course peer-reviewed, and he noted that it was argued in that paper that a negative feedback was implied in the data whether Iris was true or otherwise. So this whole discussion, really, has gone nowhere, and arrived at a stalemate, i.e. Lindzen may well yet be right.

  19. Ian Forrester

    shawnhet said: “Arrhenius only arrived at a close number by luck. There are a whole lot of processes operating that he never considered (like feedback)”.

    What a ridiculous comment. Have you read the paper by Arrhenius? I suspect not since if you had read it (and understood it) you would see that he did consider feedbacks, in particular the positive feedback of increasing water vapour content.

    His original paper can be found here:

    http://www.globalwarmingart.com/images/1/18/Arrhenius.pdf

    A word of advice to all you deniers, if you are going to quote a paper or comment on some body’s work, at least spend the time reading the paper.

    Response– It’s not as bad as you think. I happen to agree that Arrhenius’ sensitivity estimate had a lot of luck involved, although let’s keep Dr. Grumbine’s comment in perspective that the fact CO2 causes temperature to rise is simple, and unavoidable. It’s also true that Arrhenius had known (if not took it to be self-evident) that water vapor feedback was positive and would substantially amplify the warming perturbation of CO2.– chris

  20. Ian,

    I’m sorry, I did make a mistake about Arrhenius and feedback. My bad. It has been a while since I looked at that paper, and I confess I only skimmed it then ;) .

    I do stand by my comment that Arrhenius’ only arrived at the correct future sensitivity by luck, though(assuming the models are close to accurate). He also predicted that halving the CO2 would cool the Earth by 4-5C, whereas the temperature at the lowest point of the last ice age was about 8C cooler than now even though it fell to only about 2/3 of the preindustrial base level(falling to about 180ppm from about 270).

    Cheers, :)

  21. That 4200 year impact of CO2 doesn’t seem like a rigorous result, but instead a model based result that is just a ‘maybe.’ They don’t know how much of the CO2 rise and temperature rise was natural,’in the pipeline’, so the amount of sensitivity caused by the CO2 increase is not well known either.

  22. Good post.

    1) On cycles, usually when I hear a skeptic type say “we’re in a natural cycle”, they usually can’t answer clearly what that cycle is, so this post should be helpful to them.

    2) I’ve heard a lot of strange skeptic arguments, but seriously considering an asteroid impact as something that seems likely to save us from global warming is a new one.

    5) This is a very important point. Many can’t discern the difference in quality between a blog and a credible reference published in a peer-reviewed scientific journal, or peer-reviewed synthesis reports based off hundreds or thousands of objective scientific studies. There is a communication gap, however. While some summary sections of quality synthesis reports are aimed at policymakers, most peer-reviewed research has a target audience of other experts, not the vast majority of the public. How many people have the patience and expertise to read and understand the peer-reviewed scientific literature? Most contrarian material, in contrast, seems aimed directly at the general public or non-experts, and can be communicated easily through blogs and websites of dubious quality.

    Lastly, many in the general public seem to think Al Gore invented global warming (Spencer Weart’s book is a good starting point for them). This is a failure of the media and indicative of the communication gap between the scientific community and general public.

    Chris writes:

    “CA does its share of blatant personal attacks on “The Team” with titles like “Is Gavin Schmidt honest?” and digs at Dr. Mann whenever possible. Don’t act like the internet civility is one-sided, because it’s not.”

    Wow. You’re right:

    http://www.climateaudit.org/?p=419

    WattsUp tends to be a bit worse on average but that’s quite a title by CA. I haven’t a clue how any true skeptic can feign ignorance to the common childishness and mud-slinging so easily apparent on these types of blogs – from both the bloggers and readers, unless they hold the climate science community to a much higher standard than they hold for the individuals who’s opinions they agree with, which seems counter-intuitive if they care about the quality of discussion. These blogs seem more interested in provoking climate scientists and gaining a following than provoking a thoughtful discussion on science.

    For example, with the following comment:

    “Media and policymakers who blindly accept these claims are either naive or are deliberately slanting the science to promote their particular advocacy position.”

    For the record, I think Pielke is much better than this and such a comment isn’t indicative of the work he’s done over the years, but here he’s saying that anyone who doesn’t agree with him (in what turned out to be a series of very poor arguments) is ignorant or dishonest. RC’s response appropriately focused on his arguments.

    “If you’re a serious student looking to learn the issues and avoid angry bloggers, I would strongly recommend the peer-reviewed literature, academic resources, etc.”

    Very well said. The level of discourse is often much higher in this environment than in much of the blogosphere. But what of the passive non-students who nonetheless want an honest and accurate view of climate science given in layperson terms?

  23. >If you’re a serious student looking to learn the issues and avoid angry bloggers, I would strongly recommend the peer-reviewed literature, academic resources, etc.

    Some of these angry bloggers have done good work finding errors in the peer-reviewed literature. Perhaps if the peer-reviewed articles would make themselves available for replication, people would have more faith in them.

  24. MarkB,

    [edit-- Off-topic discussion about the hockey stick. I've warned you guys twice about staying on thread]

    Which cycles? I can answer that, it’s the PDO/AMO/NAO and those similar poorly understood multidecadal ocean cycles that state of the art AOGCMs still can’t quite get right. They’re the ones people worry about, i.e. was the 1976-1998 just a normal up phase of the PDO superimposed on a much smaller CO2 signal?

    Response– No. These cycles do not contribute to the longer term trend, either because of how they physically operate or by definition. There is still a lot to say about multi-decadal variability (the recent RC post on the paper by Swanson and Tsonis, the Keenlyside issues, etc) but amongst blogs they have been very much misused as “substitutes” for anthropogenic causes when this is not how it works. This is just another example of the type of misinformation one can pick up on random internet sites– chris

  25. Hi Chris,

    I find it very odd indeed that you’ve chosen at this point to snip this comment on the basis of not following thread topic. I couldn’t actually work out what your thread was really about, on this occasion, because the first half is just a vent about your frustration in communicating with skeptics. And the point I was responding to was brought up firstly by yourself in a comment. Taken as a thread about communication, which it starts as, my post was quite on-topic, and it seems embarrassing to your friends at RealClimate, I would suggest being the real reason you have snipped it. I’ll re-post it at another blog, then, shortly.

    Otherwise, keep up the great work; I enjoy reading your blog.

  26. Chris wrote July 14, 2009 @ 3:17 am:

    These cycles do not contribute to the longer term trend, either because of how they physically operate or by definition.

    I was alerted to the Tsonis et al. 2007 theory in a paper by Lindzen (2007, “Taking Greenhouse Warming Seriously”) where he interpreted the theory as such: “A very recent paper (Tsonis et al., 2007) suggests, in fact, that the surface temperature record can be accounted for by essentially superpositions of known oceanic fluctuations such as the Pacific Decadal Oscillations and the Atlantic Multidecadal Oscillations.

    I then read the Tsonis et al. 2007 paper and found that Lindzen’s interpretation of it was quite reasonable. That is, very little could be found there to reassure the IPCC that their Summary for Policymakers explanation of the so-called “unprecedented” global warming period 1976-1998 was caused entirely by increasing GHGs with 90% certainty (in fact, that it probably offset what would otherwise have been a period of cooling, IPCC2007, SPM, p. 5).

    So Swanson’s appearance the other day at RealClimate came as a huge surprise to me. I was surprised that RealClimate would touch anything like this, other than to show that it was thoroughly discredited after enough big-name skeptics had started citing it (and I don’t think many have), and I was even more surprised to then hear Swanson’s view of the paper that there was no inconsistency with the IPCC version at all.

    So I fixed upon the following issue, which appeared to be the slight-of-hand that allowed him to assert this apparently self-contradictory position: I saw that in that RealClimate post he just draws a straight line through the trend of 1976-1998, the so-called unprecedented bit, and then extends it all the way back to 1850, shows how it fits all the data in a vaguely convincing way, and then asserts that this is the underlying GHG signal. He also asserted that it wasn’t cherry-picking, and that I’d get the same line on any endpoints I could choose other than 1998-2008(??).

    Here’s the problem: I am not a statistician, but in what sense can the rise of 1976-1998 be called “unprecedented” if it is the same trend that fits all the data all the way back to 1850? It wouldn’t unprecedented anymore, would it. It’d be quite normal.

    I think this is a big problem, and I’m looking forward to your response.

    All sorts of similar questions arise to this bizarre Swanson disavowal, and I am afraid, I just cannot believe he really believes himself what he’s just written. I guess that’s my earlier point about how you can say anything on a blog, even if you’re a published scientist, and get past the peer-review, i.e. it really cuts both ways.

    Response– I don’t really buy into the Swanson/Tsonis paper, and actually I think most of it is pretty dicey. But I also agree with Swanson that it doesn’t represent an inconsistency with the much longer-term warming trend by greenhouse gases and I wouldn’t be surprised to see Lindzen misinterpreting it.– chris

  27. Alex, it is interesting to note that the Lindzen paper you quote was published in Energy and Environment. I think that says all that needs to be said about the contents.

  28. Alex Harvey writes:

    “That is, very little could be found there to reassure the IPCC that their Summary for Policymakers explanation of the so-called “unprecedented” global warming period 1976-1998 was caused entirely by increasing GHGs with 90% certainty (in fact, that it probably offset what would otherwise have been a period of cooling, IPCC2007, SPM, p. 5).”

    I’m assuming you’re referring to the Synthesis report summary:

    http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr_spm.pdf

    Perhaps you could find a quote in this report that supports what appears to be a strawman. The only quote that seems remotely related:

    “Most of the observed increase in global average temperatures
    since the mid-20th century is very likely due to the
    observed increase in anthropogenic GHG concentrations.”

    First, this doesn’t apply specifically to the more narrow 1976-1998 period you’re referring to. It’s from mid-century (we can assume 1950) through 2005 I believe.

    Second, the statement says “most”, not “all”, which allows for a significant contribution from some natural factor during this period, which renders the statement fairly conservative, considering impacts such as volcanic and solar are likely to be that of slight cooling.

    So if one is under the misimpression that PDO explains most everything, we have to note that the 1950 start point is during a PDO negative phase and 2005 (or 2008 if you’d like to extend it) is arguably in a PDO negative phase. It’s a near complete oscillation, yet compare 5-year means between these time periods. Attribution (or science in general) isn’t about coming to conclusions based on convenient correlations, though. We also have to study volcanic forcing, sulfate aerosols, and of course greenhouse gases (among other things) – things we can’t wish away.

    The 1976-1998 period is an interesting study, since the warming during this period overshot most model predictions. For the sake of convenience, we can look at an early generation model from Hansen, using a higher climate sensitivity of more than 4 C. See Figure 2:

    http://pubs.giss.nasa.gov/docs/2006/2006_Hansen_etal_1.pdf

    Real-world emissions scenarios approximated Scenario B. Note the trend in the Scenario B model and compare it to the real-world temperature trend from 1976-1998. The real-world warming appears to be several times larger than the modelled warming. It would be wrong to conclude with confidence, however, that response to CO2 had been vastly underestimated in the model. By selecting 1976 and 1998 start and endpoints, we are severely cherry-picking. It wouldn’t be a surprise if subsequently real-world trends settled down closer to the modelled prediction over the following decade, especially considering how large an anomaly 1998 was.

    Lastly, while I think it’s a serious effort done in good faith, I’m not convinced by the Swanson study. I think something like PDO (not as predictable to begin with as some might think), which is associated with somewhat more el Ninos during positive phase and la Ninas during negative phase, would have an affect on the trend during shorter transitionary periods, such as enhancing late 70′s warming or dulling the trend during recent years – not all that different from the 11-year solar cycle oscillation, which is currently in a long valley. I think it’s also another study in a long line of them that have been severely distorted for political purposes by contrarian types. I think many of them simply read what they want to read based on their own preconceptions. The RealClimate guest commentary by Swanson in that sense was long overdue. I thought Swanson’s comment is appropriate here:

    “What do our results have to do with Global Warming, i.e., the century-scale response to greenhouse gas emissions? VERY LITTLE, contrary to claims that others have made on our behalf. “

  29. Chris July 15, 2009 @ 12:16 am:

    Well, did Lindzen misinterpret it, or didn’t he? (Remember, we are talking about the earlier Tsonis et al. 2007 paper; Swanson & Tsonis 2009 seems to have been embelished a little with more apology to the IPCC that isn’t in the original paper). I say he didn’t misinterpret it, and I’ve actually read it.

    (NB. That’s why it’s really not interesting at all, Ian Forrester, that Lindzen’s paper was published in Energy & Environment; I can think through this argument myself, because it’s actually not that hard, but thanks anyway.)

    Here is the conclusion of Tsonis et al. 2007:

    The above observational and modeling results suggest the following intrinsic mechanism of the climate system leading to major climate shifts. First, the major climate modes tend to synchronize at some coupling strength. When this synchronous state is followed by an increase in the coupling strength, the network’s synchronous state is destroyed and after that climate emerges in a new state. The whole event marks a significant shift in climate. It is interesting to speculate on the climate shift after the 1970s event. The standard explanation for the post 1970s warming is that the radiative effect of greenhouse gases overcame shortwave reflection effects due to aerosols [Mann and Emanuel, 2006]. However, comparison of the
    2035 event in the 21st century simulation and the 1910s event in the observations with this event, suggests an alternative hypothesis, namely that the climate shifted after the 1970s event to a different state of a warmer climate, which may be superimposed on an anthropogenic warming trend. (Emphasis added.)

    This paper directly, and unambiguously, challenges the “aerosol cooling” piece of the standard IPCC puzzle. Without “aerosol cooling”, it follows trivially that climate sensitivity is lower than what the IPCC have been advocating. In fact, it would presumably bring sensitivity much closer to Douglass et al. 2007 value, i.e. closer to data-at-face-value, and further from the model projections.

    Tsonis, A. A., K. Swanson, and S. Kravtsov (2007), A new dynamical mechanism for major climate shifts, Geophys.Res. Lett., 34, L13705, doi:10.1029/2007GL030288.

    http://www.uwm.edu/~aatsonis/2007GL030288.pdf

    Again, the decision to draw the trend line through the 1976-1998 period, i.e. that period with the steepest gradient, is a really strange thing to do indeed. Wouldn’t you agree?

    Response– The thing is that neither of these papers are formal attribution studies, nor do they have much to say about anthropogenic influences from a variety of forcings, or even to quantify varieties of internal variability. The object of both is their hypothesis of synchronized oscillation behavior, and I personally find very little of any of it convincing, but regardless neither are suitable references for claims that anthropogenic influences are not dominant warming mechanisms in the 20th century or will/won’t be in the 21st. I’ll also place criticism on the authors for wording which doesn’t really have much to do with their paper

    As for the trendline, I don’t really have an opinion on it, you should ask someone in the statistical end of things (Tamino posted about this). By the way, I won’t be around for the next 3 days or so so I can’t moderate till then– chris

  30. MarkB,

    Here is the quote (IPCC2007, SPM, p. 5):

    There is very high confidence that the net effect of human activities since 1750 has been one of warming.6 {2.2}

    Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic GHG concentrations.7 It is likely that there has been significant anthropogenic warming over the past 50 years averaged over each continent (except Antarctica) (Figure SPM.4). {2.4}

    During the past 50 years, the sum of solar and volcanic forcings would likely have produced cooling.

    Here is the surface temperature record, according to GISS:

    http://data.giss.nasa.gov/gistemp/graphs/

    As you can see, the warming of the past 50 years didn’t actually begin until ~1976. Thus, the unprecedented warming of the past 50 years was isolated to the rise between 1976 and 1998. I don’t understand; what is the straw man argument here?

    Finally, you wrote:

    By selecting 1976 and 1998 start and endpoints, we are severely cherry-picking.

    So… that’s what I said, too. Swanson really is, severely, cherry-picking, by drawing his trend-line through 1976-1998. So we agree? It is a mistake, and a strange mistake. Why did he do this?

  31. Mark B, despite Hansen’s 2006 paper, the real world emissions did not approximate scenario B as described in Hansen’s 1988 paper, they were closer to scenario A. The whole paper is available, and you can read it for yourself. It is a little confusing where Hansen says things like the growth rate is growing.

  32. Hmm, Steve McIntyre has concluded closer to scenario B. While the CO2 emissions were equal to scenario A, the other trace gases effect in A is more than the effect of CO2.

  33. I haven’t read the blog in a while, and I have some free time today to do so, but all the Climate blogs have began to turn me off simply because of some of the nonsense arguements made by “skeptics” (as they are called). “Alarmists” are labeled the minute that they rebute any sort of science that is not valid, such as in the case of the member here Bryan Incorrectly, correcting Carol that Temperature influences Co2 and not the other way around. These individuals completely ignore scientific methods and means and then argue their point and are quick to accuse scientists (people using science to back their claims). Sometimes you can laugh at these things (like Bryans comment) and sometimes it makes you laugh, sometimes it makes your eye twitch.

  34. Pingback: The value of ‘open debate’ « My view on climate change

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s