RealClimate logo


Climate response estimates from Lewis & Curry

Guest commentary from Richard Millar (U. Oxford)

The recent Lewis and Curry study of climate sensitivity estimated from the transient surface temperature record is being lauded as something of a game-changer – but how much of a game-changer is it really?

The method at the heart of the new study is essentially identical to that used in the much discussed Otto et al. (2013) study. This method uses a simple equation of the energy balance of the climate and observations of global temperature change and estimated ocean heat uptake anomalies along with a time series of historical radiative forcing (code), in order to make inferences about the equilibrium climate sensitivity (ECS – the ultimate equilibrium warming resulting from doubling carbon dioxide concentrations) and its shorter-term counterpart the transient climate response (TCR – the warming at point of doubling after carbon dioxide concentrations are increased at 1% per year). [Ed. An overview of different methods to calculate sensitivity is available here. The L&C results are also discussed here].

Lewis and Curry use an updated radiative forcing estimate over that used in Otto et al along with slightly different assumptions over the periods used to define the observational anomalies. They use the latest IPCC numbers for radiative forcing and global temperature changes, but not the latest IPCC ocean heat content data. Their result is a 5 – 95% confidence interval on ECS of 1.1–4.1K and for TCR is 0.9-2.5K. These confidence intervals are very consistent with other constraints, from paleo or emergent observations and with the range of GCM estimates. For the TCR, arguably the more important measure of the climate response for policy makers as it is a better predictor of cumulative carbon budgets, the 5-95% confidence intervals are in fact almost identical to the AR5 likely range and similar to the CMIP5 general circulation model (GCM) estimated 5–95% range (shown below).


Figure 1: The 5-95% confidence ranges for transient climate response (TCR) taken from various studies as in Fig. TS.TFE6.2 of IPCC AR5 WG1. The green bordered bar at the top of figure is the estimated 5-95% range from the CMIP5 GCMs. blue bordered bar at the top of the figure is the 5-95% range from the Lewis and Curry (2014) study. The grey shading represents the AR5 consensus likely range for TCR.

There is a difference between the Lewis and Curry 17-83% confidence intervals and the IPCC likely ranges for TCR and ECS. However, for all quantities that are not directly observable, the IPCC typically interprets the 5-95% confidence intervals as likely ranges to account for the possibility that the model used to derive the confidence intervals could be missing something important (i.e. non-linearity that would not be captured by the simple models used in Otto et al and Lewis and Curry, which can particularly be a problem for ECS estimates using this method as the climate feedback parameter is assumed to be constant in time) [IPCC AR5 WG1 Ch10.8.2]. In this case, accounting for more complete surface temperature changes (Cowtan and Way, 2013), or the hemispheric imbalance associated with aerosol forcing (Shindell, 2014), or updates in the OHC changes, may all shift the Lewis and Curry distribution. [Ed. This expert judgement related to structural uncertainty was also applied to the attribution statements discussed here before].

The median estimate of the TCR from Lewis and Curry (1.3K) is towards the lower end of the IPCC likely range and lower than the CMIP5 median value of around 1.8K. A simple way to understand the importance of the exact TCR value for mitigation policy is via its impact on the cumulative carbon budget to avoid crossing a 2K threshold of global surface temperature warming. Using the Allen and Stocker relationship between TCR and TCRE (the transient climate response to cumulative emissions) we can scale the remaining carbon budget to reflect different values for the TCR. Taking the IPCC CO2-only carbon budget of 1000 GtC (based on the CMIP5 median TCR of 1.8K) to have a better than 2 in 3 chance of restricting CO2-induced warming to beneath 2K, means that emissions would have to fall on average at 2.4%/year from today onwards. If instead, we take the Lewis and Curry median estimate (1.3K), emissions would have to fall at 1.2%/year. If TCR is at the 5th percentile or 95th percentiles of the Lewis and Curry range, then emissions would need to fall at 0.6%/year and 7.1%/year respectively.

Non-CO2 emissions also contribute to peak warming. The RCP scenarios have a non-CO2 contribution to the 2K peak warming threshold of around 0.5K [IPCC AR5 WG1 – Summary for Policymakers]. Therefore, to limit total warming to 2K, the CO2-induced contribution to peak warming is restricted to around 1.5K. This restricts the remaining carbon budget further, meaning that emissions would have to fall at 4.5%/year assuming a TCR of 1.8K or 1.9%/year taking TCR to be equal to the Lewis & Curry median estimate of 1.3K (assuming no mitigation of non-CO2 emissions).

While of some scientific interest, the impact for real-world mitigation policy of the range of conceivable values for the TCR is small (see also this discussion in Sci. Am.). For targets like the 2 K guide-rail, a TCR on the lower end of the Lewis and Curry and IPCC ranges might just be the difference between a achievable rate of emissions reduction and an impossible one…

References

  1. N. Lewis, and J.A. Curry, "The implications for climate sensitivity of AR5 forcing and heat uptake estimates", Climate Dynamics, vol. 45, pp. 1009-1023, 2014. http://dx.doi.org/10.1007/s00382-014-2342-y
  2. A. Otto, F.E.L. Otto, O. Boucher, J. Church, G. Hegerl, P.M. Forster, N.P. Gillett, J. Gregory, G.C. Johnson, R. Knutti, N. Lewis, U. Lohmann, J. Marotzke, G. Myhre, D. Shindell, B. Stevens, and M.R. Allen, "Energy budget constraints on climate response", Nature Geoscience, vol. 6, pp. 415-416, 2013. http://dx.doi.org/10.1038/ngeo1836
  3. K. Cowtan, and R.G. Way, "Coverage bias in the HadCRUT4 temperature series and its impact on recent temperature trends", Quarterly Journal of the Royal Meteorological Society, vol. 140, pp. 1935-1944, 2014. http://dx.doi.org/10.1002/qj.2297
  4. D.T. Shindell, "Inhomogeneous forcing and transient climate sensitivity", Nature Climate Change, vol. 4, pp. 274-277, 2014. http://dx.doi.org/10.1038/nclimate2136
  5. P.J. Durack, P.J. Gleckler, F.W. Landerer, and K.E. Taylor, "Quantifying underestimates of long-term upper-ocean warming", Nature Climate Change, vol. 4, pp. 999-1005, 2014. http://dx.doi.org/10.1038/nclimate2389
  6. M.R. Allen, and T.F. Stocker, "Impact of delay in reducing carbon dioxide emissions", Nature Climate Change, vol. 4, pp. 23-26, 2013. http://dx.doi.org/10.1038/nclimate2077

236 Responses to “Climate response estimates from Lewis & Curry”

  1. 151
    Hank Roberts says:

    C’mon, Victor.

    Read the people who know what they’re talking about — both in terms of data and in terms of how science approaches these questions.

    http://www.remss.com/blog/recent-slowing-rise-global-temperatures

    You’re able to learn and that’s an opportunity.

  2. 152
    Victor says:

    #135 “Have a look at this graph and tell me what you think Occam’s has to say about it:”

    http://www.globalwarmingart.com/wiki/File:Vostok_Plot_png

    I’ve seen a similar graph. It appears on a very interesting essay I recently read, on a website recommended by Hank Roberts: http://www.aip.org/history/climate/cycles.htm

    I learned a lot from reading that essay, which by the way is really well written, very readable, clear and thorough. I was frankly surprised to see that graph, as the correlation is far clearer than one might expect. Not sure what Occam would say, but I must say I was impressed. There does seem to be a clear large-scale correlation between CO2 emission and temperature, at least in the Antarctic.

    However, as with any correlation, it has to be considered critically, along with other factors, before a causal relationship can be established. For example, there might be some third factor at work, influencing both CO2 emissions and temperature.

    Interestingly, after several paragraphs, I found this passage: “Another important clue came from some especially good Antarctic ice core records that timed precisely the changes in the levels of CO2 and methane. The levels apparently rose or fell a few centuries after a rise or fall in temperature.” As might be expected, the author manages to find a good reason for this unexpected result: “. . . it strongly confirmed that the Milankovitch-cycle orbital changes initiated a powerful feedback loop.”

    I won’t go into the details as I’m sure most of you are aware of them. Nevertheless, if you really want to know what Occam would think of THAT wrinkle: he wouldn’t like it. You know what he’d say: “Entities should not be multiplied without necessity.” And yes, this feedback loop IS necessary if one wants to argue that CO2 emissions produce global warming and not the other way round. And of course it “confirms” a theory by one Milankovitch. It also looks very much like a fudge. But what do I know, right?

    A question not considered in the essay, as I recall, is the question of what it is that prompts these cyclic CO2 emissions, assuming they are not caused by the temperature changes. Any thoughts?

  3. 153

    #144 (Danny) “…should be a data, evidence, fact based conversation. But that’s so very hard to find.”

    Indeed, it *should* be fact-based, in principle. But fossil fuel companies and their like are fighting for their profits (indeed, for their very business models.) You can’t expect them to be easily convinced; the tobacco companies before them weren’t, either. Lest I sound a bit, er, conspiratorial, please note that considerable chunks of the anti-science PR effort are in the public record (i.e.., tax donation records). A couple of instances:

    http://doc-snow.hubpages.com/hub/Climate-Cover-Up-A-Review

    http://www.desmogblog.com/2014/10/31/oil-and-gas-industry-s-endless-war-fracking-critics-revealed-rick-berman

    On the other side, there is in my estimation more emphasis on evidence and logic, because fundamentally there is solid scientific reason to be concerned, seriously concerned, about climate change, and thus no obfuscation is required. (If you look, you will be struck by the fact that there is no coherent denialist position as a whole: you will find one proclaiming that ‘everybody agrees that there has been warming; the question is, is it going to be ‘catastrophic?’ Or, ‘did we do it?’ Meanwhile the next guy is telling you that the surface temperature record has been deliberately ‘juiced’ by NASA. Indeed, it’s not infrequent to see incompatible positions taken by the same advocate, as in the case of Lord Monckton, who during the same time that he was asserting a lack of warming, was also asserting that Mars, Jupiter and Uranus were warming at the same rate as Earth, and hey, there’s no SUVs up there!) Lest you think I’m making that up:

    http://scienceandpublicpolicy.org/press/proved_no_climate_crisis.html

    Lord Monckton’s paper reveals that –

    …“Global warming” halted ten years ago, and surface temperature has been falling for seven years;

    …Mars, Jupiter, Neptune’s largest moon, and Pluto warmed at the same time as Earth warmed;

    Note the date on that release: July 2008. So Monckton ‘proved’ that the planet hadn’t warmed since 1998, and that temperatures had been falling since 2001. But other planets are warming, therefore AGW is wrong!

    Monckton (or the SPPI flack who summarized him) putties over the incoherence a little bit with that fudged wording “at the same time.” But the facts don’t support the fudge; contemporaneous comments by the Lord and others at the time are quite clear that the putative warming on Jupiter was occurring when this argument–no, ‘rhetorical device’–was being bandied about. For example, here’s an influential example (it may even have been among Monckton’s sources, and note that it was paid for by the US taxpayer, no less, via the ‘good offices’ of the Senator Inhofe of Oklahoma, who by an amazing coincidence has received close to a half million in campaign donations from the oil and gas industry):

    http://www.epw.senate.gov/public/index.cfm?FuseAction=PressRoom.Blogs&ContentRecord_id=469dd8f9-802a-23ad-4459-cc5c23c24651

    https://www.opensecrets.org/politicians/summary.php?cid=N00005582

    Note the date; the article came out in March, 2007, and the alleged extra-Terrestrial warming is clearly and obviously asserted in the present tense:

    “Mars’s ice caps are melting, and Jupiter is developing a second giant red spot, an enormous hurricane-like storm. The existing Great Red Spot is 300 years old and twice the size of Earth. The new storm — Red Spot Jr. — is thought to be the result of a sudden warming on our solar system’s largest planet. ”

    Moreover, the Jupiter warming idea has an actual, origin point–and it was considerably after the point when, according to Monckton, the Earth had already stopped warming:

    According to Philip S. Marcus, a professor of fluid dynamics at UC Berkeley, analysis of the Hubble and Keck images may support his 2004 conjecture that Jupiter is in the midst of global climate change that will alter temperatures by as much as 10 degrees Celsius, getting warmer near the equator and cooler near the south pole. He predicted that large changes would start in the southern hemisphere around 2006, causing the jet streams to become unstable and spawn new vortices.

    http://www.sciencedaily.com/releases/2008/05/080522121036.htm

    So, the *possible* warming on Jupiter *may* date from 2006–if, that is, it is real at all.

    Not much ‘there’ there, is there?

    I’ll admit that this is one of the most gratuitous excesses committed by faux skeptics. But it is by no means unique, which is why I have documented it at some length.

    But let us return to the realm of “data, evidence [and] fact.” On the ‘alarmist’ side you will find emotion, to be sure. After all, the ‘alarmed’ (as I would describe myself) believe that the evidence shows a serious threat to human health, wealth and well-being, extant now but becoming more and more serious during the lifetimes of our kids and grandkids. It’s a threat that promised to make their lives poorer, more hazardous, drearier and quite possibly shorter than they should be, or need to be. There are good reasons for emotion.

    But you will also find a coherent intellectual framework, supported by 200 years of scientific inquiry. To document that, the Spencer Weart online book already mentioned is an excellent source. Additionally, or alternately, I have a series of articles (chattier and more people- and context-oriented, but still scientifically substantial) on the early scientific history of climate change studies. You could begin that here:

    http://hubpages.com/hub/The-Science-Of-Global-Warming-In-The-Age-Of-Napoleon

    The last in the series is here:

    http://hubpages.com/hub/Global-Warming-Science-And-The-Wars

    Everything in between is accessible by clicking the ‘next’ or ‘previous’ buttons near the bottom of the article.

    One last thought. I appreciate the quote you provided, and I agree that there are some things about which agreement can potentially be reached. (I live in Georgia, where the ‘Green Tea’ coalition reached far, far across the partisan divide to force a reluctant Public Utilities Commission to include solar energy in future planning, albeit in a pretty small way.) But is it the climate movement ‘throwing conservatives under the bus?’ Or is it ‘Fox or.. talk radio’ which is framing the issue and excluding reasonable conservative voices from participation in the debate.

    I’ve spoken in person to my local Congressman, a Republican. He told me, and I believe him, that he pays extra to buy ‘green energy’ and that he likes a revenue-neutral carbon tax on principle. But you had better believe that neither stance is part of his public record. Why is that, do you suppose? It’s a shame–though I disagree with him on a number of points, he is a smart and thoughtful guy. It’s too bad that he apparently doesn’t feel safe to speak his mind. And it is to the detriment of the overall policy conversation.

  4. 154

    “…climate scientists genuinely concerned about the future of the planet can’t just talk among themselves, preaching endlessly to the choir. They need to be able to communicate with non-scientists, since the vast majority of those who make policy all over the world are not climate scientists.”

    Victor, it’s more than a little ironic that you’d put that ‘novel’ idea forth on a blog maintained by the volunteer efforts of climate scientists who have been moderating dozens (and sometimes hundreds) of daily comments for the better part of ten years now, not to mention writing original posts and administering the site in other ways. Most of them are also regular commentators on other blogs and in public media, some have participated in public ‘climate debates’, and also written books on the topic for the general public. To wit, two examples:

    http://hubpages.com/hub/The-Long-Thaw-A-Review
    http://hubpages.com/hub/Michael-Manns-The-Hockey-Stick-And-The-Climate-Wars-A-Summary-Review

    Seems you are also in denial about climate science communication…

  5. 155
    Victor says:

    Hot off the press! My comment in response to today’s IPCC report in The Guardian (slightly edited):

    If you consider all those living in every corner of the world now dependent on: heating generated by gas, oil, coal, charcoal; electricity generated by gas, oil and coal; gasoline produced from oil; affordable food prices made possible by the relatively low costs associated with farming and the transportation of agricultural commodities, thanks to the relatively low cost of petroleum products,

    and

    you take into account the possibility of unintended consequences, such as the disastrous increase in food prices due to the government imposed turn to biofuels — which incentivised farmers to switch from food production to fuel production,

    in addition to the fact that subsidies to low income people won’t be of much use if the resources they depend on are no longer available for them to purchase,

    then you will realize what a complete calamity the world would have on its hands if these totally insane recommendations were adopted. Resistance to such proposals is not limited to the oligarchs controlling the fossil fuel industries, that’s pure rhetoric. Once ordinary people wake up to the sacrifices expected from them by these starry eyed “scientists” they will revolt. And we’ll have a calamity on our hands every bit as disastrous as anything that might be produced by global warming over the next hundred years.

  6. 156
    dhogaza says:

    Victor:

    “Regardless of how many of you agree regarding “the science,” if you can’t formulate your arguments in a manner that makes sense to non-climatologists your recommended policies will not be adopted.”

    Learning is a two-way street, not a responsibility of scientists alone. The person who wants to learn has a responsibility to make an honest effort to understand the subject being taught. No matter how good a teacher is, there will be some students who are either unwilling or unable to learn.

    In your case, I suspect “unwilling” is the cause, but I’m slowly changing my mind and the other possibility seems more plausible with each of your posts …

  7. 157
    dhogaza says:

    Victor:

    “And by the way, as far as Mssrs. Dunnnig and Kruger are concerned, a great many scientists, not only ideologues, share views similar to mine and are raising similar questions.”

    Name one scientist who has expertise in the field who claims that a monotonic rise in CO2 must result in a monotonic rise in temperatures regardless of changes in other forces, which is what your arguments about “correlation” boil down to. You argue that essentially increasing CO2 must negate all other forcings in the system. No expert in the field, regardless of their position on the magnitude of feedbacks etc, argues that.

    So. Name one.

    And stop concern trolling. I’m getting embarassed for you.

    Who do you think the science-denying drivel you post on your site and here will convince, anyway? Not anyone with a science or technical background who is interested in learning climate science, that’s a given.

  8. 158
    Steve Fish says:

    Victor, atmospheric CO2 concentration and temperature are closely related. When CO2 concentration increases the temperature follows by increasing and when temperature increases CO2 follows by increasing. Conversely when CO2 decreases temperature follows by decreasing and when temperature decreases CO2 follows by decreasing. This has to do with positive feedback and the relationship has been validated to a near certainty by thousands of studies in the lab and the field. If you don’t understand this relationship do you think that it, therefore, must be wrong? This is a website about science not post-modernist claptrap. Go educate yourself?

    Steve

  9. 159
    MARodger says:

    Victor @150/152.
    You are now become troll-like in your comments. Where are these “great many scientists” you talk of? And are their views truly “similar to” your views? While you consider these questions, be aware that it has been the case up-thread where you have picked up a scientific issue and transformed it into something else of your own making.
    Your view specifically here is that the power of CO2 to warm the climate and produce AGW is not “estabilished fact” but is questionable.
    So where are these “great many scientists”?

    As for the difficulties science has overcome to establish the age of CO2 measurements in ice cores, your citing of Wm. Ockham (whose razor you apparently are singularly incapable of wielding) is sorely inappropriate. Here’s some light reading for you. It is the reference from the website you belittled – Shakun et al (2012). And be aware: none of the 9 authors of that paper will be on your list of the “great many scientists” which you really do need to provide for us if you wish to avoid becoming considered a troll.
    As for the website you belittle, I remember that website back over ten years ago. It’s good to see it being kept up-to-date and referencing recent papers like Shakun et al (2012). Good job!!

    Thinks. Who is it who says of people who deny the power of CO2 as an established agent of climate forcing “they couldn’t do better as promoters of CAGW… even if they required paying”? That’s right. It was the Arch-AGW-denier Richard Lindzen. So he’ll be another one not on your list.

  10. 160
  11. 161
    dhogaza says:

    Victor:

    You might consider giving the Occam bit a rest. You’re just boring people with it. We all know about Occam’s Razor. You greatly overestimate its usefulness in science. It is possible that your faith in Occam is what leads you to oversimplify things and to reject science which, in your mind, provides overly complicated theories to explain evidence. The world is a complex place.

    At your level of expertise and your personal ability to observe the world, application of Occam’s razor to mechanics as you do to climate science would lead you to reject relativity in favor of Newtonian mechanics. You’d be wrong to do so. You are wrong to do with climate science, too.

    Something else to consider – if you’re going to overturn climate science, you must first understand climate science. Thus far you are tilting at windmills and slaying strawmen, because you don’t understand the subject. That’s what makes you so laughable in the eyes of the people who have been patiently attempting to educate you. Your slain strawmen might impress your peers in the world of art and the like, but anyone with an understanding of the science will be left banging their heads against the wall in frustration and your stubborn refusal to learn. Or to even accept that working experts who have devoted their lives to the subject are the teachers here, and that you are the student.

    I know everything I write, like everything everyone else has written, will fall on deaf ears. Inventors of perpetual motion machines are every bit as stubborn as you, just as wrong, and share your belief that they’re proving modern physics wrong. In other words, you, like them, are nothing but a tiresome, physics-ignorant crank.

  12. 162
    Hank Roberts says:

    > Victor … AIP History … I learned a lot from reading that

    Congratulations, you’ve now learned some of the very basic early history of climate science. Did you read the portion of the book (it’s far more than an essay) that tells you the limits of what he’s covered?

    You raise reasonable questions. He discusses how they were worked on up to the beginning of the age of computers, and mentions how they began to be answered, but only after large computers came into use.

    From that point — the mid-1950s or so — you need to look further. The links behind the “Start Here” button (top left of every page at RealClimate) will take you further.

    I’m glad you found Weart’s History useful.
    Next, along with the Start Here links above, I would recommend you seriously consider a little essay by a right-wing, gun-slingin’ flame-breathing ‘ibertarian who doesn’t take his own advice, about this subject, but nevertheless long ago gave this excellent advice; you’d find his recommended approach gets you much better answers: How To Ask Questions The Smart Way.

    Showing you’ve read Weart and understood that much is a good start.

    (I’m basically recommending what worked for me, to the degree it has thus far. YMMV.)

  13. 163
    Hank Roberts says:

    The blog software busted that link, How To Ask Questions The Smart Way is at:
    http://www.catb.org/esr/faqs/smart-questions.html

  14. 164
    Hank Roberts says:

    PS for Victor — the introduction from Weart’s online book points out that climate is complex.

    The scientists who labored to understand the Earth’s climate discovered that many factors influence it. Everything from volcanoes to factories shape our winds and rains. The scientific research itself was shaped by many influences, from popular misconceptions to government funding, all happening at once. A traditional history would try to squeeze the story into a linear text, one event following another like beads on a string. Inevitably some parts are left out. Yet for this sort of subject we need total history, including all the players …. This Web site is an experiment in a new way to tell a historical story. Think of the site as an object like a sculpture or a building. You walk around, looking from this angle and that. In your head you are putting together a rounded representation, even if you don’t take the time to inspect every cranny. That is the way we usually learn about anything complex.

    Revisit Weart’s book; the most recent revision dates are shown there; it’s continuing to be updated, following the subject.

    A couple of thoughts about Ockham:

    To paraphrase Holmes: When you have shaved away all the factors that don’t affect climate, what remains, however surprising, is considerable.

    Or, an observation attributed to Einstein, though I think never cited to a source: “Everything should be made as simple as possible, but not simpler.”

  15. 165
    Victor says:

    #157 dhogaza

    “Name one scientist who has expertise in the field who claims that a monotonic rise in CO2 must result in a monotonic rise in temperatures regardless of changes in other forces, which is what your arguments about “correlation” boil down to. You argue that essentially increasing CO2 must negate all other forcings in the system.”

    Wow, you people are really blowing my mind. This post and others like it reveal a truly alarming inability to comprehend what I wrote about correlation. I can’t tell if it’s stubborn adherence to dogma or just plain thick headedness. How can you call yourself a scientist if you can write such rubbish? I’ve tried to avoid this kind of language, but I’m truly disturbed when those claiming scientific expertise fail so miserably to understand something so basic as correlation.

    Scientists have found a correlation between smoking and incidence of cancer. That correlation exists, and can clearly be graphed, regardless of all the many complicating factors, such as age, heredity, number of packs a day smoked, environment, working conditions, time delay, etc. No one claims there is a single cause of cancer, just as no one claims there is a single cause of global warming. But that doesn’t excuse scientists from the responsibility of demonstrating a clear correlation between a proposed cause and its effect. Why is this so difficult for you people to grasp?

  16. 166
    Victor says:

    To begin, I want to thank Hank Roberts, the first on this thread to give me credit for asking a reasonable question. Well, Hank, I’ve been asking lots of reasonable questions, the sort of questions any ordinary person would ask — but I have not, for the most part, been given reasonable answers, i.e, answers based on simple logic and common sense. Instead I’ve been informed very rudely that I don’t have the right to ask reasonable questions because I lack the expertise to challenge anything “the experts” have claimed. The argument from authority. Sorry but I’m not impressed.

    #161 Once again Mr. Dhogaza:

    “At your level of expertise and your personal ability to observe the world, application of Occam’s razor to mechanics as you do to climate science would lead you to reject relativity in favor of Newtonian mechanics.”

    Here you demonstrate a complete misunderstanding of Occam’s razor — which doesn’t at all surprise me. It’s not just the simplest explanation which satisfies Occam, it’s the simplest explanation consistent with the evidence. Einstein revealed hidden assumptions in Newtonian mechanics that made it inconsistent with the evidence. Relativity, which does take into account the evidence Newton missed, is in fact not only a simple, but remarkably elegant theory, a perfect example of Occam’s razor in practice. By comparison, Newtonian mechanics is far more complex.

  17. 167
    SecularAnimist says:

    Victor wrote: “They won’t challenge you, as I have.”

    The only thing your comments here have “challenged” is the patience of other commenters.

    Indeed, I greatly admire the patience, politeness and respect with which other commenters have attempted to educate you about some of the basics of climate science, in response to your tiresome litany of long-since, many-times-over debunked denialist talking points, your smokescreen of hand-waving at “the philosophy of science”, and your trollish rhetorical fallacies.

    Personally, I think they have been wasting their time, since you are obviously not here to learn anything.

    Victor wrote: “a great many scientists, not only ideologues, share views similar to mine and are raising similar questions”

    That is simply false.

  18. 168
    ezra abrams says:

    as a liberal, I’m supportive of climate science, and the idea that we are doing bad things to our planet

    however, this posts raises doubts: after what, 20 years of intense study, one new study is a “game changer” ?
    That implies that all that was said before is not reliable

    I also have a problem with all the statistics; maybe it is unavoidable, but it looks like pathological science (n rays, polywater): sort of constant statistics chasing small signals that vary

    maybe i”m overstating, but then again maybe you should read up on psychology of argumentation,

  19. 169

    “A question not considered in the essay, as I recall, is the question of what it is that prompts these cyclic CO2 emissions, assuming they are not caused by the temperature changes. Any thoughts?”

    They ARE caused by temperature changes. The initial temperature ‘push’ comes from the orbital forcing, and as oceans warm, CO2 is outgassed. This creates further warming via well-understood mechanisms, which leads to yet more warming. That is what ‘feedback’ means.

    In the present instance, by contrast, CO2 is a direct forcing, rather than a feedback.

    http://www.realclimate.org/index.php/archives/2014/10/climate-response-estimates-from-lewis-curry/comment-page-4/#comments

  20. 170

    “However, as with any correlation, it has to be considered critically, along with other factors, before a causal relationship can be established. For example, there might be some third factor at work, influencing both CO2 emissions and temperature.”

    See more at: http://www.realclimate.org/index.php/archives/2014/10/climate-response-estimates-from-lewis-curry/comment-page-4/#comment-616861

    Well, sure, it might. But Occam’s Razor would enjoin us from considering that possibility, according to someone I was reading recently…

  21. 171

    “Once ordinary people wake up to the sacrifices expected from them by these starry eyed “scientists” they will revolt.”

    – See more at: http://www.realclimate.org/index.php/archives/2014/10/climate-response-estimates-from-lewis-curry/comment-page-4/#comments

    Again, what sacrifices do you think will be required? Why do you think that? Who has put these ideas forth?

    So far, we have no idea to the answers to any of these questions. I’ve already once linked to work from serious economists which explicitly contradict your contentions. And I’d go further and say that there are some analyses which find net economic *benefits.*

    Since the Summary Report is just out, let’s quote from it: Given reasonable assumptions, avoiding 2 C is like to cost global economic consumption “1 % to 4 % (median: 1.7 %) in 2030, 2 % to 6 % (median: 3.4 %) in 2050, and 3 % to 11 % (median: 4.8 %) in 2100 relative to consumption in baseline scenarios that grows anywhere from 300 % to more than 900 % over the century” before accounting for co-benefits and costs.

    http://report.mitigation2014.org/spm/ipcc_wg3_ar5_summary-for-policymakers_approved.pdf

    And “…the consideration of economic costs and benefits of mitigation should include the reduction
    of climate damages relative to the case of unabated climate change.” Projected climate damages could well reach 2% by mid-century if baseline scenarios continue.” As for benefits, those might number job growth, public health, and others, in addition the the reduction of climate damages. One recent report making that case (albeit in diffusely written fashion) is this:

    http://newclimateeconomy.report

    “As the impacts of climate change grow larger, the potential harm to economies will increase. What this report shows, however, is that low-carbon policies can also generate strong growth in the medium term (5–15 years)…”

    That’s scratching the surface–but it’s worlds beyond anything you’ve supplied, Victor. Care to ‘put up’ the bases for your ‘mitigation alarmism?’

  22. 172

    #166, Ezra–As I read it, the whole point of this post is that the paper is NOT a game-changer at all, as claimed by–well, whoever it was that said so.

  23. 173
    MartinJB says:

    Victor, I hate to tell ya’, but it’s YOU who does not understand correlation and the use of correlation to support hypotheses. At this point, after numerous, reasonable responses to your occasionally naive and oftentimes insulting questions and statements, I don’t think there’s any point in trying to convince you otherwise. You exhibit a stunning level of arrogance that appears to brook no self-doubt.

    But please, answer me one thing. What statistical training or practice in your background makes you SO very convinced that you understand correlation and the scientific method better than a lot of folks who have significant statistical and scientific training and experience under their belts?

  24. 174
    Hank Roberts says:

    Victor, let me go on pretending I’m a nice, patient guy, as I find that invariably worth doing — I always need more practice; you’re helping me with that.

    When you use debate tactics, you’ll always catch someone with them.
    Always. Either a regular here who’s tired of the same old same old, or another new reader who’s itching for the same kind of public attention.

    But you won’t catch the scientists, who won’t bother answering you. Instead you get responses from the usual regular readers, almost all students.

    So — think about how you come in here.

    You start off asking elementary questions, and raising issues dealt with — as Dr. Weart’s history teaches — through at least the last 50 years of study. Yes, you can still find them being asked at Morano’s blog, and you sound like he’s captured your imagination.

    If so it’s in a very small box. Please, try to get outside that.

    You’re posing those same old, same old questions as though you’re the first person you know to think of them.

    If you are that isolated — how can you be an academic?

    Guessing: You may be retired, or be teaching somewhere with, um, a less than competent science department, or you’re pulling our leg. That happens often enough that most people here say something approximating “pull the other one, it’s got bells on” — remember, on the Internet nobody knows you’re not a dog, unless you give a real name and show your work.

    Ask smarter questions that show you did the “Start Here” reading — ask new questions.
    That will get you attention from people who appreciate questions.

    The climate scientists here show their work. You can look their work up. You know how to do that.

    Many of the ordinary folks who’ve made the effort, also show their work. Look at the right sidebar, look at the top “Start Here” bar, look at the links behind folks — Kevin McKinney, for a strong example of someone who’s done the heavy work of learning this stuff.

    Me, I try to emulate what a decent librarian would offer.

    You said you wanted a debate. In a library? In a study hall? No worky.

    Science does its debating in the journals, not on blogs. That’s not just my opinion, you can look it up. The tools of debate don’t get answers in the sciences.

    Do you have political position that makes it hard to believe what’s published? Then you should read one of the best science essays written on the web, a few years ago: Because As We All Know, The Green Party Runs the World.

  25. 175
    Hank Roberts says:

    Oh, by the way, for Victor:
    You expected “… answers based on simple logic and common sense.”

    Spencer Weart does address that problem explicitly, in some detail.

    Simple logic and common sense were used, and the answers they gave tested.
    Turns out they were wrong.

    Seriously, you’re asking questions that recapitulate the evolution of this science — showing that you’re unfamiliar with all the work that’s been done. You might re-read this, if you did read it:
    http://www.aip.org/history/climate/summary.htm

    Re-asking the questions answered there isn’t asking questions the smart way.
    That’s what the footnotes are for.

    It attracts debate, which, as you said, you came here looking for.
    There’s a Monty Python routine you may be familiar with that ensues.

    I’m done, I think. Can’t imagine I can contribute more to your questions until you’ve generated better questions — and at that point, more knowledgeable people will find you interesting, with luck, and join in.

  26. 176
    Hank Roberts says:

    Hm, blog software consistently mangling the last link, which should be:

    Because As We All Know, The Green Party Runs the World.
    http://www.rifters.com/crawl/?p=886

  27. 177
    Steve Fish says:

    Re- Comment by Victor — 2 Nov 2014 @ 9:28 AM, ~#155

    Regarding your comments that are – “Hot off the press!” And “in response to today’s IPCC report,” I can only say wow. Other than being factually incorrect and poorly written, it’s great!

    Steve

  28. 178
    Danny Thomas says:

    Kevin, Re: #153

    Thank you for your response. I want to preface my comments with letting you know I’ve spent a few days on Watts and taken a firm beating (would be happy to provide a link or two if that would add to my credibility). I kinda expect the same to happen here because folks tend to let emotions take over.

    So I’ll ask that you and others here bear with me as I’m just beginning my journey towards an understanding of Climate Change and I have to start with a basic question that I can’t get a concrete answer for. Why is CO2 such a “bad guy”? My seriously AGW buddy (and I can provide his website, he’s given permission) said (para mine) I don’t know, go to the National Academy of Science. I’ve gone there and there is some evidence, but no definitive conclusion. I’ve gone to IPCC and get the same. Google, same. Watt (of course it’s NOT AT ALL a bad guy there–as if breathing on Venus would be easy for us humans LOL.). JC, eh, maybe, maybe not. I can’t for the life of me understand how if that is unsettled IPCC can say we have to cut it to the extent proposed. I can see it’s can be seen as pollutive at some level, but I don’t see it at today’s level. I’ve been to the NOAA Mauna Loa site to run the numbers for myself. Yes, it’s increasing, and that increase has increased in the past decade. But if it’s such a known “bad guy” why is it still debated?

    So many out there have already made determinations, on both sides. It’s thick with politics. But seemingly there is so much riding on such a basic question that I’m frankly confused.

    I don’t wanna stir things up, I’m no troll. There is no place for those of us beginning this quest. There is AGW, and “absolutely not” sides. There are some in what I perceive as “the middle” (accepting Global warming is occurring based on evidence, but unclear if cause is natural or man caused or maybe even a bit of both). I’m in that middle.

    My buddy has provided some stuff but he can’t seem to see that his politics muddies the picture. But to his credit, he’s got me researching.

    I see there is psychology of Global Warming communication and that bothers me as I’m not aware of something like that for say, chemistry or physics. I come from a sales background and selling an intangible requires some psychology. This should be tangible and it bothers me that it’s not.

    And I’m not understanding why There’s a Watts side, and Judith Curry side and a Real Science side. But since there is, why aren’t folks here over there and folks there over here?

    In other words, as you say it seems there is no “company line” on the “skeptical side” (I can’t use denier because my perception is very few deny global warming but do deny causes). But there are reasonable discussions (as well as unreasonable attacks) of some of the evidence for AGW.

    Short comment is the science seems far from settled. Am I missing something (I’m sure I’m missing A LOT)?

    Reminder, I’m just beginning developing my understanding. It’s a tough ask, but can you or others approach this with me from that perspective. I’m cringing by hitting the submit button.

    Oh, and if it’s inappropriately posted please let me know.

    Thanks in advance.

  29. 179
    Hank Roberts says:

    Victor, here’s a snippet from well known climate scientist and climate blogger James Annan’s comment about the paper that’s the subject of this thread:

    Friday, October 03, 2014
    Much ado about sensitivity
    http://julesandjames.blogspot.com/2014/10/much-ado-about-sensitivity.html

    There’s a new paper in Climate Dynamics, by Lewis and Curry, with a central sensitivity estimate of 1.6C with a 90% range of 1-4C, based on energy budget analyses over the instrumental period, updated to the present day, also taking account of the newer AR5 forcing estimates. I don’t find it particularly exciting, the authors cite several recent papers with similar results including Aldrin and Otto et al. I wrote about those papers some time ago, and I think these posts (1, 2, 3) still stand. I’ve commented before on my objections to Lewis’ method, and especially the sleight-of-words with which it is described, but (as I’ve also emphasised) I don’t think this substantially affects the results in this application.

    Clearly, the longer the relatively slow warming continues, the lower the estimates will go. And despite what some people might like to think, the slow warming has certainly been a surprise, as anyone who was paying attention at the time of the AR4 writing can attest. I remain deeply unimpressed by the way in which this embarrassment has been handled by the climate science insiders, and IPCC authors in particular. Their seemingly desperate attempts to denigrate anything that undermines their storyline (even though a few years ago the same people were using markedly inferior analyses of this very type to bolster it!) do them no credit.

    One weakness of these energy-budget type of analyses, that I believe Lewis and others could easily address, is to demonstrate ….

    ————
    (at the original page, “Aldrin and Otto et al.” and “posts (1, 2, 3)” are hyperlinks — go there for that).

    The difference is — he’s published what he’s thinking, and people can read it. That’s informed skepticism, or what Peter Watts was talking about at that other page I hope you’ve read.

    This isn’t “Victor” against the climate monolith.

    This is Victor wandering onto the sidelines of a game played by pros.

    You ought to have a look at stephenschneider.stanford.edu/Books/SAACS/saacs_book.htm — Science as a Contact Sport

    Well informed people can play rough. We bystanders can get educated.
    Wander onto the field proclaiming ignorance? Not a good move.

  30. 180
    spilgard says:

    Shorter #155, stripped to the breathless, alarmist core. I’m off to my swooning-couch:

    every corner of the world! dependent! affordable food prices! low costs! low cost! unintended consequences! disastrous increase! prices! government imposed! low income people! no longer available! complete calamity! totally insane! Resistance! rhetoric! ordinary people! sacrifices! starry eyed “scientists”! revolt! calamity! disastrous!

  31. 181
    dhogaza says:

    Victor:

    “Relativity, which does take into account the evidence Newton missed, is in fact not only a simple, but remarkably elegant theory, a perfect example of Occam’s razor in practice. By comparison, Newtonian mechanics is far more complex.”

    Wow. I won’t say more. The humor factor here is so large that commentary isn’t really necessary …

  32. 182
    Victor says:

    In response to all the above:

    First of all: yes I am arrogant. Guilty as charged. It’s in my nature. I’m not proud of it, but it often emerges, even when I try to suppress it.

    Second: no, I’m not cowed by all the putdowns. I may not be a climate scientist, but I pride myself on my critical thinking skills. Trying to snow me with your superior knowledge won’t work, especially when you reveal your inability to grasp simple, straightforward questions and process reasonable objections. I’ve been involved in several controversies at various times, involving topics on which I was very well informed, and never have I attempted to pull rank on anyone based on my superior knowledge or bolster my position by invoking some consensus view. As I see it, if you can’t explain yourself, you’re better off remaining silent.

    As for the rest, I’ll let one of our most distinguished living scientists speak for me:

    “My impression is that the experts are deluded because they have been studying the details of climate models for 30 years and they come to believe the models are real. After 30 years they lose the ability to think outside the models. And it is normal for experts in a narrow area to think alike and develop a settled dogma. . .

    Of course I am not expecting you to agree with me. The most I expect is that you might listen to what I am saying. I am saying that all predictions concerning climate are highly uncertain. On the other hand, the remedies proposed by the experts are enormously costly and damaging, especially to China and other developing countries. On a smaller scale, we have seen great harm done to poor people around the world by the conversion of maize from a food crop to an energy crop. This harm resulted directly from the political alliance between American farmers and global-warming politicians. Unfortunately the global warming hysteria, as I see it, is driven by politics more than by science. If it happens that I am wrong and the climate experts are right, it is still true that the remedies are far worse than the disease that they claim to cure.”

    Freeman Dyson

  33. 183
    Victor says:

    Someone sent me a link to the following paper, which I have now read: “Global warming preceded by increasing carbon dioxide concentrations during the last deglaciation.”
    http://sciences.blogs.liberation.fr/files/shakun-et-al.pdf

    Some comments:

    The title is misleading, because the temporal relationship revealed by the raw data is reversed: as they themselves note, the warming preceded the CO2 emissions.

    To account for the discrepancy, they propose a model based on delayed reaction, feedback mechanisms and a “seesawing of heat between the hemispheres.” “These findings, supported by transient simulations with a coupled ocean–atmosphere general circulation model, can explain the lag of CO2 behind Antarctic temperature in the ice-core record and are consistent with an important role for CO2 in driving global climate change over glacial cycles.”

    I’m not going to attempt an analysis or critique of their model per se because I’m clearly not qualified to do that. For all I know it could be correct.

    What concerns me is the thinking behind their approach in general, not the solution they propose. To clarify, let’s suppose the raw data revealed that the CO2 actually did come first, followed by the warming. If that were indeed the case, it would tend to confirm what they already assumed, that CO2 emissions produce large-scale increases in surface temperature. And, given that they saw exactly the sort of results they were expecting, I’m wondering whether they’d have felt any need to explain it. What would there have been to explain, right? Would they have any incentive at all to develop a model explaining data they were already expecting to see? And what sort of model could that have been, given their conviction that CO2 is what produces the warming, not the other way round.

    So. Back to reality. We have a situation that requires an explanation because it’s contrary to the investigator’s expectations, and in fact contrary to everything they’ve been arguing for over many years, no doubt. That definitely needs explaining. But if the timing were reversed and they were getting what they expected then obviously there would be no need (i.e., desire) to produce an explanation, would there?

    I know most of you think highly of this research and are convinced it’s right — but what this looks like to me is, very simply: confirmation bias. When your data don’t confirm your expectations, then you need to construct a model “explaining” the discrepancy. But if the results had met your expectations, then obviously there would be no need to construct such a model. I also see a violation of Occam’s razor, because the only “necessity” for the model they’ve produced in response to data that on its face appears to falsify their theory, is to “explain” the discrepancy so it fits their theory after all.

    Judging from the responses I’ve been receiving on this blog, I seriously wonder whether any of you are going to see the problem, or at least admit you see it. To me, this sort of thing goes to the heart of the objections I’ve been raising regarding correlation, Occam’s razor, etc. There are very fundamental scientific principles at work here that many climate scientists either can’t recognize or refuse to consider.

  34. 184
    MARodger says:

    Victor@150/152/155/165/166.
    You have now emphatically placed yourself across the line. Due to your longevity here prior to that placement, you are probably due an explanation (which will likely be utterly ignored by you).
    You have always provided comments here that showed you being capable of happily plonking your standard firmly down in denialist pastures. That is why you have been challenged so strongly. But the mitigating aspects of your earlier comments are now gone and replaced with the language of a simple-minded gobby git (that is you display gross ignorance and do so with no leeway for any doubt in your mind). By doing this you leave any scientific discussion entirely behind. I would recommend our hosts send further comments of yours to the borehole.

    Victor the troll @155.
    You present “slightly edited” versions of your own comments about an unlinked Guardian press report (presumably this one) on the recent IPCC report. In my humble opinion, this is obviously borehole material that slipped past over-streched moderators. If you want to abuse the hospitality of RealClimate properly, why not put a link to your grubby little website while you are about it? Then the unedited version of your wise comment will be available to us along with what it actually was you were commenting on.
    For the record, the Guardain quote that was being rebutted by Victor the Troll@155 was:-

    “Currently fossil fuels provide more than 80% of all energy but the urgent need to cut planet-warming carbon emissions means this must fall to as little as a third of present levels in coming decades, according to a leaked draft of the Intergovernmental Panel on Climate Change (IPCC) report seen by the Guardian.”

    Victor the troll@165.
    Your vaccuous comment@134 makes plain that it is you spouting the “rubbish” not your accuser. Did you not comment thus @134?:-

    “In order to establish a causal relation between f.f.e. and g.w., you have to at the very least establish a clear correlation between those two. NOT between and among all the different factors, but JUST THOSE TWO. And if there are anomalies, you need to do more than simply point to certain factors that might explain the discrepancy. Because there is a difference between explaining something and explaining it away.”

    And as an exemplar of such “clear correlation” did you not explain thus?:-

    “From a certain point (roughly 1850), we see a steady rise in f.f.e., but when we look at warming we see several ups and downs, including at least one very dramatic downswing, from ca. 1940 to 1950 and of course the hiatus from ca. 1998 to present.”

    QED, here lies the rubbish and your persistence with it is inexcusable outside the borehole.

    Victor the troll@166.
    Questions and answers are two sides of the same coin. The comment @162 was pointing you again to a source of reasoned answers for reasonable questions. You say you’ve “been asking lots of reasonable questions” but this is not the case. The comment @162 congratulated you on sone “very basic” learning. I’m of the opinion that that “very basic” learning was not taken fully on board. Note what the “nice, patient guy” Hank Roberts tells you @174 “Ask smarter questions that show you did the “Start Here” reading.” That is ‘stop acting the troll.

    Regarding Newton/Einstein, you demonstrate very well a profound failure in grasping the concept engendered in Ockham’s razor, and indeed failure of your “understanding of fundamental scientific principles” which you have attempted to brandish more than once down this comment thread .
    Newton was not wrong. This is because “the evidence Newton missed” post-dated his death. Newton was correct in a world where Maxwell and Michaelson & Morley had yet to be born and where the human ability to accurately plot the orbit of Mercury did not exist. And envoking Ockham’s razor to rule between Newton & Einstein is purile. Ockham’s razor will be always blunted when it confronts the bedrock of scientific evidence.

  35. 185

    #177–Well, I kind of like the words “unintended consequences”, in that portions of the WG3 report do quite a bit of work to try to unravel how to avoid and/or manage unintended consequences.

  36. 186
    Hank Roberts says:

    > Hot off the press

    the political position that makes it hard to believe what’s published.

  37. 187
    Radge Havers says:

    Victor @~ 182:

    “First of all: yes I am arrogant.”
    “…I pride myself on my critical thinking skills.”

    See that’s the problem with arrogance: lacking suffient self-awareness to evaluate when you’re wrong and lacking sufficient social skills to pick up on potentially corrective cues. It’s like living in a parochial, self-aggrandizing bubble.

    If you had any critical thinking skills at all, you would understand that throwing a technique at something you don’t understand and hoping something sticks is pointless and just part of a futile exercise in confirmation bias, if not outright nihilism. You’re only fooling yourself.

    =====

    “An arrogant person considers himself perfect. This is the chief harm of arrogance. It interferes with a person’s main task in life—becoming a better person.”
    ―Leo Tolstoy

    How to destroy somebody:

    “Pretend inferiority and encourage his arrogance.”
    –Sun Tzu

  38. 188
    Victor says:

    #184 plus several other posts along similar lines.

    I’m surprised that the sort of vicious personal attacks perpetrated by MARoger and others are permitted on a scientific forum. What does that tell us about the objectivity of these self-appointed “climate scientists”? Does behaving like a child make you more convincing?

    All I’ll say in response to Mr. Rodger is this:

    As I’ve already explained, a correlation is NOT a summary of all possible causes in all possible cases. It’s a demonstration that a coherent relationship exists — a prerequisite to any claim of causality. If you can’t understand that, then you have no right to call yourself a scientist.

    Oh and one more thing: Mind Your Manners!

  39. 189

    Danny, you ask:

    “I have to start with a basic question that I can’t get a concrete answer for. Why is CO2 such a “bad guy”?”

    My answer would be that CO2 isn’t a ‘bad guy.’ However, it is definitely possible to have too much of a Good Thing. Since you are a guy, think of the example of testosterone: too little in your system and you will likely see loss of libido, energy and even muscle wasting, among other adverse consequences. But too much and you are at risk for, well, risky behavior. According to WebMD, “Taking all the factors together, researchers found that the healthiest men overall had testosterone levels between 400 to 600 nano grams.” Similarly, CO2 in the atmosphere has a ‘mama bear’ level that is ‘not too much, not too little, but just right.’ Just what that might be, exactly, is not easy to say, partly because of uncertainties in the science, and partly because not all parties have the same interests: Swedes might prefer a different ‘answer’ than Indians. But it’s quite likely lower than the roughly 400 ppm we have now; you may be aware of 350.org, which advocates for a return to that level of CO2 concentration.

    The framing that ‘alarmists’ think CO2 is a ‘bad guy’ is, in my view, nothing but a denialist rhetorical device–see as example, Lord Monckton’s ‘comic’ spelling of it as ‘Sciotoo’ (or something like that.) But the reality is that climate science tells us that CO2 is responsible for keeping us out of ‘snowball Earth’ conditions, and allowing life to thrive. Increasing CO2 levels are responsible for pulling us out of the recurrent Ice Ages that have characterized the last few millions of years of geological history. Indeed, one of the seminal figures in developing the theory of CO2 in climate change, Svante Arrhenius, was quite clear back in 1896 that he saw CO2-driven warming as a good thing, leading to a more ‘equable’ climate. (Of course, he *was* a Swede and not an Indian.)

    http://hubpages.com/hub/Global-Warming-Science-And-The-Dawn-Of-Flight
    http://hubpages.com/hub/Global-warming-science-press-and-storms

    In modern times, it has become abundantly clear that humans are indeed raising atmospheric concentrations of CO2 by, primarily but not exclusively, burning fossil fuels. The first person to show this was Guy Callander, a remarkable scientific amateur. (Though a technologist by credentials and career path, he *was* also the son of, and lab assistant to, one of the most eminent physicists of the day.) His paper on this came out back in 1938:

    http://hubpages.com/hub/Global-Warming-Science-And-The-Wars

    However, his conclusions were not generally accepted until the late 1950s, when computers were able do the massive computations needed to trace radiative exchanges throughout the depth of the atmosphere–work associated with the names of Gilbert Plass and Lewis Kaplan–and careful oceanographic work was able to show that the seas were not such an efficient sink of CO2 that they would ‘clamp’ CO2 levels despite human emissions. It was around that time that it began to dawn on people that warming might not be all good. Official concerns about the possible bad consequences began to be voiced at an official level in the 1970s, but there was little real knowledge about what we now term climate ‘impacts.’

    As I wrote in another article:

    But during the 70s concern deepened; a 1970 MIT study warned of “widespread droughts” and “changes of the ocean level,” a 1974 CIA report foresaw the world’s food supply at risk, and in 1977 the National Academy of Sciences envisioned a whole suite of consequences as “adverse, perhaps even catastrophic.” Concern spread globally, and international conferences assessed human health impacts (1979) and called on all governments to develop climate change policies (1985).

    http://hubpages.com/hub/Global-Warming-Science-A-Thumbnail-History

    The upshot was the Earth Summit, the Framework Convention, and the establishment of what is arguably the most significant ad hoc agency every, the International Panel on Climate Change, tasked with summarizing what published scientific literature had to say about climate change.

    There is now a large body of literature summarizing what warming we may expect, depending on the collective choices we make over the coming decade or two. If we continue with business as usual, we may come close to the worst scenario considered in AR5, which is RCP 8.5. For that CO2 concentration trajectory, we would, even if climate sensitivity is on the low side of the estimated band, likely exceed the ‘sort of safe’ level of warming, which by somewhat arbitrary consensus, is 2 C. The consequences of that are summarized here:

    http://doc-snow.hubpages.com/hub/The-Two-Degree-World

    But if we are less fortunate, sensitivity will be higher, and in that case we could see nearly 5 C of warming, landing us in the ‘5 degree world’:

    http://doc-snow.hubpages.com/hub/The-Five-Degree-World

    For more discussion of the possible outcomes vis a vis our choices, see here:

    http://doc-snow.hubpages.com/hub/Six-Degrees-Choosing-Our-Future

    All of this is drawn from Mark Lynas’s 2008 book summarizing the then-state of the art research. It’s considered at length here:

    http://doc-snow.hubpages.com/hub/Mark-Lynass-Six-Degrees-A-Summary-Review

    It’s dated a bit, now, but the big picture isn’t radically different; the just-released synthesis report notes threats to food security, coastal populations and infrastructure, public health, and economic damage. Naturally, forecasting something that depends on climate, weather, *and* future human actions is fiendishly difficult. But everything that we do know points to the conclusion that a prudent humanity would choose Not To Go There.

  40. 190
    SecularAnimist says:

    Victor wrote: “There are very fundamental scientific principles at work here that many climate scientists either can’t recognize or refuse to consider.”

    That is absolute nonsense.

    Why Victor’s torrent of vapid denialist trollery has not been consigned to the Bore Hole is beyond me.

  41. 191

    Victor, are you really oblivious to the fact that you *read into* the research a confirmation bias, and then imputed it to the researchers as if it were established fact? And then further concluded that readership here ‘wouldn’t see the problem?’

    I think we do. It appears to be interior to your cranium–or more plainly put, you are imagining things.

  42. 192
    MARodger says:

    So according to Victor the Troll @183, if science establishes a set of data after having first established a scientific view (let us call this dataA for After and scientific viewB for Before) any research (researchA) that attempts to explain inconsistencies within dataA w.r.t. viewB should be dismissed if researchA is found to give support for the viewB.
    I think that in Victor’s version of science if the dataA had been discovered prior to viewB, then the esablished scientific view would be viewA not viewB and presumably no inconsistencies would have been found at that point in time. That is until dataB (the stuff on which viewB was based) comes to light. Now I assume Victor the Troll and his “understanding of fundamental scientific principles” is saying that at this point science would carry out researchB which would, oh no, explain the inconsistencies within dataB w.r.t. viewA and give continuing support to viewA. So in this alternate version viewB is never established.
    This is, of course, an exact reversal of the original situation swapping A for B and B for A. Perhaps according to Victor the Troll@183, this means all science, or maybe only the science he disagrees with, is entirely subject to “confirmation bias.”

    This lack of faith in science and scientists may be why Victor the Troll is wary of naming those “great many scientists” he keeps telling us hold views similar to his own. Certainly Freeman Dyson isn’t one of them although Victor does cite Dyson @182. I think Victor should leave Dyson alone. The man is in his 90s now, not the age for doing useful original science. Besides, you will note in the e-mail exchange Victor the Troll quotes from @182 that Dyson says “Most of us are sceptical and do not pretend to be experts” and Dyson does also countenance the possibility of being wrong on AGW, although Dyson remains a little hazy concerning the full consiquences of such error. Dyson therefore doesn’t sound like anybody’s star witness to me.
    (Perhaps a double posting – captcha acting up.)

  43. 193
    Radge Havers says:

    Danny @~ 178

    CO2

    Too much CO2 is bad because bad things happen when the planet gets too hot. I don’t get what you’re not getting here.

    “debated”
    Most credible scientists aren’t debating. The debating is a denialist thing. It puts an emphasis on rhetorical devices. The discussions that matter most in science take place in a properly peer reviewed environment. This is what you should be concerned with. A consensus has emerged among top scientists about the broad issues.

    There’s a new emphasis on communicating science because the subject is difficult and people are being confounded by propaganda; which as has been pointed out to you already, is happening because the stakes are high. That we’re even having this discussion shows that obfuscation works. IMO that’s because our education system doesn’t provide sufficient training in science meta-literacy, let alone in science and critical thinking.

    Now I can understand how people get messed up on this subject, but I’ve also seen this type of question come up in comment threads numerous times where it just goes round and round in endless circles– which leaves me wondering: What the hell?

    At some point you just have to do some of your own homework. Go to the Start Here link at the top of this page where you’ll get the real science from real scientists, not the windbag wannabes. Go to Skeptical Science which is beautifully accessible and geared toward answering specific questions. Go forth and read. Read, read, read your ass off while thinking things through.

  44. 194

    “…the remedies proposed by the experts are enormously costly and damaging, especially to China and other developing countries.”

    …is purely assertion without evidentiary support–though there *is* evidence that, had we not delayed really meaningful globally-coordinated action by the better part of two decades, the assertion would have been unequivocally false. The more we delay, the more dislocation and expense increase–as reaffirmed in the just-released synthesis report.

    http://www.ipcc.ch/report/ar5/

  45. 195
    Steve Fish says:

    Re- Comment by Victor — 3 Nov 2014 @ 1:55 AM, ~#183

    Thank you for the humor. I guess you either didn’t actually read the Shakun et al. (2012) paper or couldn’t understand it. I know, this science stuff is just so very hard.

    Steve

  46. 196
    Victor says:

    #192 MARodger

    “So according to Victor the Troll @183, if science establishes a set of data after having first established a scientific view (let us call this dataA for After and scientific viewB for Before) any research (researchA) that attempts to explain inconsistencies within dataA w.r.t. viewB should be dismissed if researchA is found to give support for the viewB.”

    That’s the first insightful comment I’ve seen from you yet, Mr. R, so congratulations. (How’s that for a backhanded compliment?) I think your participation in this discussion is doing you some good.

    Yes, that does seem unreasonable. If one has established a particular view and one then encounters evidence that one’s view could be wrong, it’s perfectly natural to make an effort to explain the discrepancy, and also perfectly reasonable. However, at this point there is a great danger of confirmation bias, so the discrepancy must be handled with great care. C.B. is, by the way, a very subtle problem that many excellent scientists succumb to despite the best intentions.

    The difficulty I have with the paper in question is not so much that they all too conveniently introduce complexities (Occam again) in an effort to account for the discrepancy, but they neglect to mention that it’s a problem at all, and in fact present it as though it somehow supports their position. This is reflected in their very misleading title, which actually reverses the picture presented by the data itself, before it’s been “massaged.”

    If they had said something like:

    “this result, very frankly surprised us, as it appears, on its face, to contradict one of the basic assumptions of modern climate science. Nevertheless, as we explored the larger context we discovered some very interesting mechanisms that might reconcile the raw data with the long established view.”

    such language would convince a skeptical reader like myself that they were aware of the problem and looking for a reasonable explanation. That would NOT be confirmation bias, because they were being honest and open about the problem at hand. Instead, they simply ignore the problematic nature of the evidence and proceed with a very complicated and in fact convoluted set of mechanisms that might or might not explain the discrepancy though they never really consider that second possibility.

    It’s confirmation bias because they are looking only for a model that confirms viewB and seem oblivious to the possibility that the data might not support it. The possibility that this data might suggest a very different model is not something they even consider. The larger problem, of course, has to do with the principle of falsification. To be truly scientific a theory must be falsifiable. If, however, one refuses to recognize that possibility, regardless of what sort of evidence one encounters, then one is undermining the validity of that theory.

    It’s all too easy to fall into these sort of traps. I’m not accusing the authors of anything unethical. I’m just pointing to some weaknesses in their approach (and the all too easy acceptance of their “solution”) that need to be addressed.

  47. 197
    MARodger says:

    Danny Thomas @178.

    It may be that you should be asking your questions on the Open Thread rather than here. Your questions are off-topic here. Note, the nonsense you see from a certain commenter here is also off-topic but the behaviour of that commenter is frankly unwelcome on any thread.

    But as you are here…

    I don’t think I would describe the bad in CO2 as others have here.

    Is CO2 “bad”? It is totemic of AGW, yes. And AGW is “bad.” It is totemic because it is the biggest driver of AGW. However it provides only about half the total positive AGW forcing (53% as of 2011), although a proportion that will continue to rise with time.
    But as well as being big, CO2 is also stubborn and has a very long history. That is what makes CO2 “bad.”

    Regarding CO2’s long history, the sun was a lot less hot at the beginning of the solar system, about 75% the strength. Yet we had oceans on Earth. The one mechanism that has kept Earth at a remarkably constant temperature over the last 4 billion years is believed to be CO2. The idea is well known (so I’m not sure why it is being described as a “new theory” here, possibly some new aspect of the process being described. But the link will save me an explanation.)
    As well as that, when things happen to the the Earth’s temperature, CO2 is always in on it, famously during the recent ice ages, but also in events further back, climate has reacted to changes in CO2, now no-longer acting as a control knob on temperature but forcing change (as per the PETM) and amplifying changes that do occur. Building up the paleo-record of CO2 is an on-going effort but so often you will see that CO2 record does wobble when the climate does. (Eg the Antarctic ice cap 14 million, 34 million years ago & the CO2 record.)
    That is the long history.

    CO2 is stubborn but it is not the only stubborn greenhouse gas. CO2, CFCs, HCFCs and HFCs all stick around for millenia. Methane only sticks around a decade and Nitrous Oxide a century. If we hadn’t controlled CFC, HCFC & HFC, they would be posing the same threat as CO2. But we have controlled them.
    About half the CO2 we emit ends up quickly absorbed into the ocean & biosphere. After 1,000 years another ~25% will be likewise absorbed. The rest remains up there, in the words of one of our hosts here at RealClimate “effectively for ever” or as the concluding line of Archer et al (2009) puts it, The “generally accepted modern understanding of the global carbon cycle indicates that climate effects of CO2 releases to the atmosphere will persist for tens, if not hundreds, of thousands of years into the future.”

    All this means I think, not that CO2 is bad, but that it is large changes in atmospheric CO2 that are “bad.”

    .

    I also note you ask why folk over here don’t visit over there, although you point out there are many ‘over there’s. My own view is that the various ‘over theres’ are peopled by posters and commenters who live on a different planet. That is why they apparently hold such egregious views – the planetary climate they discuss is not that of Earth.

    Denialists would have us believe that the consensus is a bunch of scientists toeing the official line which refuses to admit that the consensus is/could-be built on flawed evidence. If this were so, you would expect a ‘them and us’ situation – the consensus brown-nosing the establishment line (or whatever) and the true sceptics working tirelessly to knock the evidence into shape.

    But we don’t see that. And what we do see perhaps provides outsiders with strong evidence that it is actually the so-called climate sceptics who are denying the evidence before us. To paraphrase the opening of a famous novel “All climate consensualists are alike; each climate denier is unhappy in his/her own way.” Denialists do not agree with the consensus and they fractiously disagree amongst themselves as to why.

    Of course within the consensus there is a boiling pot of views on the danger mankind is stoking up for itself. There are many alarmed by what the IPCC may be underestimating. At its extreem but still within the science – Will we suffer a Shakhova event next year, or any time this century, or ever? What of Hansen’s 5m sea level rise predictions for 2100? But the consensus (and even the existence of a consensus is disputed by some deniers) does sign up to the IPCC findings that AGW requires preventing/mitigating, that the world does not want to go to the place where unmitigated AGW is very likely to send us. And because that place is not fully undestood, there remain possibilities for it being a very very bad place to be.

  48. 198
    marcus says:

    #196 Victor, it has been explained to you thoroughly, that your conclusion that the onset of sea level rise predates the industrial warming (based on that wikipedia graph) is in error, and also why it is.
    Why do you have this still on your blog post?

    All the best

  49. 199
    SecularAnimist says:

    Victor quoted Dyson: “the remedies proposed by the experts are enormously costly and damaging, especially to China and other developing countries.”

    That’s absolutely false — just as false as your claims about climate science.

    In reality, expert analysis has shown that the “remedies” necessary to mitigate global warming by reducing CO2 emissions will cost a tiny fraction (less than one tenth of one percent!) of the world’s economic growth over the next century. Whereas failing to do so will impose massive costs on the entire world’s economy, which will hit the developing countries hardest.

    Moreover, the development of renewable energy sources — principally solar and wind — is already a driver of economic growth in the developing world, not only in China and India which are aggressively building large-scale solar and wind generating capacity but in less-developed countries and regions, e.g. rural Africa and India, where many people who have never had access to electricity (and never will have access to large power grids) now have plentiful electricity from village-scale distributed solar power.

  50. 200
    Aaron D says:

    #196 Victor

    As many on this thread have been repeating in relation to what you write–wow. I’m not a scientist nor do I play one on science blog threads, but even I can tell that your reading of Shakun et al. (2012) is embarrassing. Why? They explicitly address the thing you say they don’t address in the very first paragraph. Then they show why that doesn’t explain what can be measured and observed. With much less cause in experience and training, I nevertheless join the other posters: just stop.