Christopher Monckton, birther – Part IV

Words fail. Previous entries here, here, and here.

Hurricane Sandy and the Climate Hens

Image courtesy of NASA, used under Creative Commons

Hurricane Sandy is one for the record books in a number of senses, and as New York and the world struggle to grapple with its enormity, some discussion has turned to climate change. A topic that has been damningly absent from discussion in the U.S. Presidential election.

It is inevitable that when anyone anywhere tries to talk about climate change in relation to things in the here and now rather than some murky, distant future, a particular group descends to cluck their tongues and admonish everyone that climate change can’t be tied to any individual event (a proposition that is not true, and grows increasingly less defensible as the field of fractional attribution matures). This group includes many who also fall into the camp of those who style themselves as non-partisans or above the “tribal” nature of climate debates. The parallels with Jay Rosen’s larger media critique of the View from Nowhere have been noted by Michael Tobis among others.

Dave Roberts has a thoughtful piece about this phenomenon. He refers to this group as climate “scolds” in contrast to climate hawks (and yes, I do have my own problems with the latter moniker). And while I do think that “scold” captures a lot of the flavor of the group Roberts is describing, I think the hawk vs. “___” setup favors a different term for the group: climate hens.

Image courtesy of Flickr user “Ann Blair”, used under Creative Commons

Climate hens by and large acknowledge the human perturbation of the climate system. But they are very, very hesitant to highlight (or are even downright resistant to) the idea that humans are shaping the present climate in ways that are affecting the public now. This may be because it doesn’t jibe with what they learned about climate years ago. It may be because they view erring on the side of making climate change seem more serious than it is to be as bad or worse than denying that it’s a problem. It may be because they don’t really understand climate science very well- Eric Berger and Roger Pielke Jr., for instance, are two climate hens that have displayed a remarkable ignorance about basic aspects of climate science pertaining to natural variability in a warming world. (Pielke Jr. is also infamous for playing bait and switch by turning conversations about human contribution to extreme events into discussions about an economic signal in normalized disaster losses.) Whatever the reason, climate hens are just plain uncomfortable with people attempting to tie extreme events to our increasing influence on the planet’s climate.

Roberts points out, correctly and convincingly, that the climate hens are clucking about a problem that doesn’t really exist- at least not the one that they’re ostensibly worried about. When the general public sees something like the record US heat, the summer drought, or a hurricane like Sandy, and they start asking about global warming, they don’t really want a belabored lecture on fractional attribution or paleoclimatic precedents that the climate hens think should determine the answer. What the public is looking for is some way to connect this thing- that scientists are telling them is real and a real problem- to their own experiences of the world. That’s what we humans do. Climate hens are, by mistake or by design, frustrating one of the best avenues of facilitating public recognition of climate change as a problem they need to take seriously. Roberts frames it this way:

That’s the key missing ingredient on climate change: not a technical understanding of stochastic modeling, forensic attribution, and degrees of probability, but a visceral, more-than-intellectual sense of what climate change means. Most people simply lack a social and ethical context for it, so they end up jamming it into other, more familiar contexts (“big government,” “environmental problem,” “liberal special interest group”).

A storm like Sandy provides an opportunity for those who understand climate change to help construct that context. It provides a set of experiences — a set of images, sounds, smells, feelings, experiences — that can inscribe climate change with the cultural resonance it lacks. That’s what persuades and motivates people: not the clinical language of science, but experiences and emotions and associations. Of course communicating scientific facts is important too, but it’s not the primary need, nor the standard by which other communications should be judged. What scolds often do is interpret the language of emotion and association through the filter of science. That’s neither helpful nor admirable.

And this perspective has supporters amongst those studying climate communication. Elke Weber (2010) makes this point:

Behavioral research over the past 30 years strongly suggests that attention-catching and emotionally engaging informational interventions may be required to engender the public concern necessary for individual or collective action in response to climate change… To the extent that time-delayed consequences of our actions do not attract the attention or generate the concern ex-ante that they would seem to warrant ex-post, behavioral research provides some corrective actions. The concretization of future events and moving them closer in time and space seem to hold promise as interventions that will raise visceral concern.

The science of tropical cyclogenesis in a warming world is undoubtedly complex and uncertain- a point I’ve been making for years. But when the public starts asking questions about climate after an event like Hurricane Sandy, they aren’t looking for navel-gazing about ensembles of modeling runs, wind shear, and overwash sediment coring. They are asking for a way to connect something they keep hearing they are supposed to care about to things they already do. The proper response to such questions is not, as the climate hens would have it, to shut them down and turn them away. And it should go without saying that nor is it a reason to overstate the connections between our increasingly heavy influence on the climate and extreme events like Hurricane Sandy. Rather, the appropriate response is to treat the questions for what they are: an invitation to talk about climate change in a way that is meaningful to a curious but decidedly lay public. Climate change means sea levels rising, it means storm surge increases, it means heavier precipitation events (Schaeffer et al., 2012; Sriver et al., 2012; Shepard et al., 2012; Min et al., 2011). If Hurricane Sandy makes these threats more concrete, if it moves them closer in time and space, if- in Roberts’ words- it provides “a set of images, sounds, smells, feelings, experiences”, we should absolutely be talking about it. And perhaps something good will come of this disaster. Clucking from the climate hens be damned.

References

• Min, S.-K., X. Zhang, F. W. Zwiers, and G. C. Hegerl (2011), Human contribution to more-intense precipitation extremes, Nature, 470(7334), 378–381, doi:10.1038/nature09763.
• Schaeffer, M., W. Hare, S. Rahmstorf, and M. Vermeer (2012), Long-term sea-level rise implied by 1.5 °C and 2 °C warming levels, Nature Climate Change, doi:10.1038/nclimate1584.
• Shepard, C., V. Agostini, B. Gilmer, T. Allen, J. Stone, W. Brooks, and M. Beck (2012), Assessing future risk: quantifying the effects of sea level rise on storm surge risk for the southern shores of Long Island, New York, Natural Hazards, 60(2), 727–745, doi:10.1007/s11069-011-0046-8.
• Sriver, R., N. Urban, R. Olson, and K. Keller (2012), Toward a physically plausible upper bound of sea-level rise projections, Climatic Change, 1–10, doi:10.1007/s10584-012-0610-6.
• Weber, E. U. (2010), What shapes perceptions of climate change?, Wiley Interdisciplinary Reviews: Climate Change, 1(3), 332–342, doi:10.1002/wcc.41.

Making an honest hack out of Fred Pearce in five easy steps

Image courtesy of Flickr user “bLOGOS/HA HA”, used under Creative Commons

Attempting to convince those in the grip of denialism is like trying to nail Jell-O to a wall. Take the case of the DDT-holocaust lie. No sooner has one false claim been thrown out (e.g. DDT ban in Malaysia in 1999 resulted in an increase in malaria) and shown to be nonsense than a new claim bearing no particular relation to its predecessor is deployed. Rather than chase down every single mutually contradictory claim made by those perpetuating the lie, I invite them to put themselves on record in a manner that makes their claims easily assessable.

In order to claim, as rubbish journalist Fred Pearce has, that anti-science environmentalism is responsible for “blanket opposition” to DDT use in fighting malaria resulting in a “virtual ban” for “more than three decades” and “millions of deaths”, one only has to satisfy a handful of conditions:

1. Quantify how many, from where, and over what time interval the “millions of deaths” are supposed to have occurred.
2. Demonstrate that there was a ban (actual or “virtual”), restriction, or other meaningful impediment to using DDT for malaria control (vs. for example agricultural spraying) in place for all deaths claimed in the above.
3. Demonstrate that had DDT been implemented, all deaths claimed in the above would have been prevented (taking into consideration obvious confounding factors like the increase in resistance to DDT).
4. Demonstrate that had DDT been implemented, the overall net result including health, economic, and environmental problems would have been positive- in other words, that using DDT would have resulted in more good than harm.
5. Demonstrate that the cause of DDT not being implemented in all of the above cases was specifically attributable to “blanket” anti-science environmentalist opposition, rather than science-, economics-, efficacy-, and logistics-based reasons from professional science and health organizations like the World Health Organization, or implementation problems that had nothing to do with Silent Spring (such as replastering and bedbug concerns raised in places like South Africa).

Pretty simple. If you can’t satisfy the conditions, you don’t get to toss corpses at the feet of supposed anti-science environmentalist opposition arising from Silent Spring. Just how serious a case do people like Fred Pearce and Roy Spencer really believe they have?

My guess? Most won’t even  get past the first question or two.

Tom Fuller and Malaria – A Case Study of Denialism and the Backfire Effect

[I'm going to assume that most people who visit this blog are familiar with denialism and its hallmarks. If not, check out a good rundown from Denialism blog.]

Longtime readers are already familiar with Tom Fuller’s denialism on climate, e.g. here and here. Lately, Fuller has decided to throw his lot in with the DDT-holocaust lie.

The meme that anti-science environmentalist hysteria resulted in a ban on DDT use, resulting in millions of deaths from malaria, is fairly prevalent among the fringe American right wing but few places elsewhere. It’s championed by anti-regulatory front groups (e.g. CEI), climate denialists (e.g. Roy Spencer), and more recently rubbish journalist Fred Pearce.

It is of course demonstrably false. Make no mistake, there was indeed a resurgence of malaria after some decades of relative success in suppressing it. This resurgence had nothing to do with anti-science environmentalist hysteria. The reasons for it are not shrouded in mystery, but are rather mundane and (unfortunately for those looking to smear environmentalists) pretty much what a sane person would expect: financial problems, complacency, political instability, growing resistance, cost-benefit tradeoffs with alternatives due to scientific, economic, and practical concerns, and the like (Nájera et al., 2011; Cohen et al., 2012).

This was pointed out to Fuller. But Fuller tends to think with his gut, so he was not about to let pesky little things like reality stand in the way of a good blood libel. So he attempts to marshal some “evidence” in support of Pearce’s use of the lie. His first attempt is to blame the 1972 domestic ban on DDT use in the US- that had explicit exemptions for public health needs such as disease vector control- for a decline in DDT use in Sri Lanka that began in 1964. This is, to put it mildly, rank idiocy. Its nonsensical nature is pointed out.

Unsteadied, Fuller spends the next few comments telling people like myself that we “suck”, we’re on acid, and that environmentalists are like skinheads.

You might think this invective is the dawning of a realization of defeat. But the human psyche is a funny thing. When someone is shown that their position is stupidly, laughably wrong, if the position is tied to their ideological beliefs, it will have some interesting effects. Rather than accept their wrongness, they will actually discount the the refuting evidence and reaffirm their position even more strongly (Nyhan and Reifler, 2010). So after the brief period of insults free of any actual arguments, Fuller goes casting about for something else that will justify the DDT-holocaust lie. And look what happens along the way:

Fuller starts out just trying to justify Pearce’s use of the word “arguably”, and says that, well ”[t]here are a substantial number of people who sincerely believe” in the DDT-holocaust lie, so Pearce is okay [October 23rd, 2012 at 12:16 pm]. His attempts to defend Pearce are shown to be wrong and he goes looking for other ones. As he does, he becomes more and more invested in the idea not just that Pearce was okay to spread the lie because he said it was “arguably” true, but that it is in fact absolutely true [October 24th, 2012 at 4:45 pm; October 24th, 2012 at 4:52 pm], and then goes still further and claims Pearce was really understating (!) the case [October 24th, 2012 at 9:28 pm]:

If Pearce is guilty of anything, it appears to be understatement.

This is the backfire effect on full, magnificent display.

And of course, denialism is nothing if not predictable, so Fuller’s evidence included the following: citing a four year hiatus of DDT use in South Africa that actually had nothing to do with anti-science environmentalist hysteria related to Silent Spring and was, it should go without saying, not responsible for “millions of deaths” (Mnzava, 2001; Cliff et al., 2010). Claiming that a 1999 ban on DDT caused an increase in malaria infections in Malaysia- this is what the trend in malaria infection actually is:

Citing the science, economic, and logistics-based decisions of the World Health Organization as anti-science environmentalist hysteria. Copypasta’ing walls of text from Senate testimony-fudger and all-around innumerate DDT evangelist Donald Roberts. And claiming that DDT was “stopped several decades [before the year 2000 in Mozambique], because 80% of the country’s health budget came from donor funds, and donors refused to allow the use of DDT” , despite DDT being the main method of malarial control until 1993. Claiming this, I should add, hours after it was pointed out as a falsehood in response to another commenter.

There is no admission of being wrong about any of things Fuller tossed out that were demonstrably false. There is no attempt made to maintain coherence of evidence or narrative (science and logistics are conflated with anti-science hysteria; the World Bank and WHO are conflated with hippies; the “millions of deaths” are supposed to have taken place in Africa in the 60s, then the 90s, then in the Americas; etc.). Causality is, several times, thrown completely out the window. And the sillier and more contradictory the claims grow, the more convinced Fuller becomes that the DDT-holocast lie is true.

All of this behavior will seem irrational and bizarre to many onlookers. And it is bizarre, if we were really talking about a person who was legitimately interested in looking at the reality of the situation. But of course, that’s not at all what’s taking place. What’s taking place is very classic behavior associated with motivated reasoning. It’s certainly not rational, but it is all too familiar. Though the topic is different, the dynamics are the same with respect to the denial of the reality and seriousness of anthropogenic climate change. Some people are just not going to be reachable by reality-based arguments. Taking a fact-based approach will actually cause some of them to be even more committed to their incorrect beliefs. Fortunately, though, the same social science that has illuminated this irrational behavior offers us some ways to bypass it. Hopefully I will have more to say on that later.

Note: In comments, Fuller says he was not defending Pearce’s use of “arguably”.

References

• Cliff, J., S. Lewin, G. Woelk, B. Fernandes, A. Mariano, E. Sevene, K. Daniels, S. Matinhure, A. Oxman, and J. Lavis (2010), Policy development in malaria vector management in Mozambique, South Africa and Zimbabwe, Health Policy Plan, 25(5), 372–383, doi:10.1093/heapol/czq008.
• Cohen, J., D. Smith, C. Cotter, A. Ward, G. Yamey, O. Sabot, and B. Moonen (2012), Malaria resurgence: a systematic review and assessment of its causes, Malaria Journal, 11(1), 122, doi:10.1186/1475-2875-11-122.
• Mnzava, A. E., B. L. Sharp, D. J. Mthembu, D. le Sueur, S. S. Dlamini, J. K. Gumede, and I. Kleinschmidt (2001), Malaria control–two years’ use of insecticide-treated bednets compared with insecticide house spraying in KwaZulu-Natal, S. Afr. Med. J., 91(11), 978–983.
• Nájera, J. A., M. González-Silva, and P. L. Alonso (2011), Some Lessons for the Future from the Global Malaria Eradication Programme (1955–1969), PLoS Med, 8(1), e1000412, doi:10.1371/journal.pmed.1000412.
• Nyhan, B., and J. Reifler (2010), When Corrections Fail: The Persistence of Political Misperceptions, Political Behavior, 32(2), 303–330, doi:10.1007/s11109-010-9112-2.

Fred Pearce continues to be rubbish

Image courtesy of Flickr user “Editor B”, used under Creative Commons.

Not content with lying about positions scientists don’t actually hold, passing off his opinions as reporting, engaging in the kind of “he said, she said” false equivalency that has been so toxic in media coverage of climate, and just generally getting things wrong, here’s Pearce perpetuating the free market/anti-regulation think tank lie about DDT bans causing millions of deaths:

When Rachel Carson’s sound case against the mass application of DDT as an agricultural pesticide morphed into blanket opposition to much smaller indoor applications to fight malaria, it arguably resulted in millions of deaths as the diseases resurged.

[Although there was a big push to do away with agricultural DDT spraying, its use to fight malaria was not banned. DDT use continued apace in some countries and declined in others for top down reasons rather than environmentalist-driven anti-science hysteria, including resistance in mosquitoes, political instability, preferences for pyrethroids (which also killed cockroaches) or netting (which didn't involve coating one's walls with a sticky unpleasant substance), and genuine-science-based health concerns of governments.]

But hey, it’s totally fine to say something that egregiously, hideously untrue as long as you mumble “arguably” into your sleeve, at least according to Pearce’s cheerleaders.

Pearce’s lie comes in the context of the latest hippie punching fad, which is to equate environmentalist fears about GMOs, nuclear power, and fracking with evolution denial, climate denialism, and other hallmarks of the anti-science right. This is approaching something of a cottage industry among people who seem to be garnering fewer eyeballs on topics like climate change than they once did.

There are three facts of relevance here, in my opinion:

1. There are unquestionably environmentalists who have and promote fears about certain technologies that are unsupported or in contradiction to the balance of scientific evidence.
2. This anti-science vein is in no way equivalent to, in terms of political legitimacy at the levers of governmental power, that right wing anti-science beliefs enjoy.
3. The actual, problematic anti-science beliefs of environmentalists are often conflated with issues that have nothing to do with science in order to make the problem seem larger than it is. This is counterproductive.

I think point number 1 is hugely important. The work of Dan Kahan and others (e.g. Kahan et al., 2011) has shown pretty convincingly that egalitarian-communitarians interpret scientific evidence in a way that conforms to their preexisting worldviews just as hierarchal-individualists do. I would like to see anti-science fears about GMOs and nuclear power either marginalized or preferably reversed by effective messaging and education. I vehemently believe that GMOs and nuclear power are going to be necessary tools in dealing with our energy and agricultural needs in the future, and that climate change probably increases their importance.

Point 2 is something that I trust is not in any way controversial or requires further discussion.

For those of us who believe point 1 is a legitimate problem, point 3 effectively knee caps efforts to ameliorate it. When people conflate issues that enjoy no clear scientific consensus, such as the environmental impacts of fracking, with denial of evolution or the reality of anthropogenic climate change, they are injecting a false equivalency that muddies the waters of discourse and prevents positive movement on the issue. The same goes for conflating dislike of business practices of certain agricultural companies and economic/national security concerns over nuclear power with denial of evolution or climate change.

If Pearce or the others who have taken up this latest meme stuck to what actually was equivalent, their complaints would look a great deal less serious. So they have to over-egg the pudding. This not only gives the appearance of more substance, it also generates more acrimony and page views. Whether the latter is intentional or not, it’s certainly not productive in actually addressing the problem, which requires understanding the actual scope and potential strategies for overcoming what environmental anti-science exists. And make no mistake, there are people doing just that.

But Fred Pearce is not one of them.

UPDATE: Some folks over at Collide-a-scape are trying to pin the decline in DDT use in some countries in the 60s against malaria on a 1971 US domestic ban. Yes, something in the 60s is being attributed to something that happened in the 70s.

Setting aside the timeline idiocy, as I stated previously, actual examination of the causes of malaria resurgence simply does not bear this out. Nor does it support in any way Pearce’s ghoulish lie that environmentalists are somehow to blame for it or millions of deaths. In the course of providing others with some references, I came across some additional reasons for malarial resurgence. It turns out that weakening of programs due to financial shortfalls, premature complacency, and intentional expiration of short term programs- in addition to aforementioned factors like resistance and political instability- are responsible not just for a decline in DDT use, but a decline in malarial-eradication programs generally (Cohen et al., 2011;  Nájera et al., 2011). Both papers should be accessible without a subscription.

References

• Cohen, J., D. Smith, C. Cotter, A. Ward, G. Yamey, O. Sabot, and B. Moonen (2012), Malaria resurgence: a systematic review and assessment of its causes, Malaria Journal, 11(1), 122, doi:10.1186/1475-2875-11-122.
• Kahan, D. M., H. Jenkins‐Smith, and D. Braman (2011), Cultural cognition of scientific consensus, Journal of Risk Research, 14(2), 147–174, doi:10.1080/13669877.2010.511246.
• Nájera, J. A., M. González-Silva, and P. L. Alonso (2011), Some Lessons for the Future from the Global Malaria Eradication Programme (1955–1969), PLoS Med, 8(1), e1000412, doi:10.1371/journal.pmed.1000412.

A new LGM reconstruction, with implications for climate sensitivity

LGM Ice Sheet Extent from Clark et al., 2009

First off, it’s important to note that the paper has only appeared in CPD, it still has to pass review. However, I’m going to comment on the results for two reasons. Mundanely, I have a sliver of free time now, and I don’t know that the same will be true after the paper’s (presumed) eventual publication. More importantly, however, I think it’s safe to say that its results will be misinterpreted to the same or even a greater extent than Schmittner et al., 2011 (hereafter S11) was. The mainstream press largely ignored some potential reasons to be skeptical of that paper’s results (discussed by RealClimate and Skeptical Science among others, as well as by one of the paper’s authors in an interview with me at Planet 3.0). And of course the denialist echo chamber distorted the results ludicrously, going so far as to erase an entire portion demonstrating them to be consistent with the larger body of evidence on climate sensitivity (e.g. Knutti and Hegerl, 2008) and inconvenient to dismissals of the danger posed by unchecked GHG emissions.

With the throat clearing out of the way, here’s how things stand. Fyke and Eby (2012) offered some criticisms of S11. They objected to some of the proxy data used, and more importantly, pointed out that the model used (a version of the UVic model, which is more akin to simplified EMICs than GCMs) simply couldn’t produce realistic behaviors of key atmospheric processes which caused it to underestimate ECS:

[T]o explore the potentially large dependence of Schmittner et al.’s results on the choice of climate model, we carried out a new model simulation with the most recent version of the UVic ESCM in which the atmospheric latitudinal profile of heat diffusion varies in response to the global average atmospheric temperature anomaly (the “Mod” simulation in Fig. 2). This functionality gives a new model with much improved fit to both Antarctic and Arctic LGM temperatures as recorded by ice cores, yet still retains an excellent fit to low-latitude temperatures. Notably, and most importantly, we found that this model ranks very well with respect to the relative RMSE test, but with a much higher ECS (3.6°C) than similarly ranked models in (1). As suggested in (1), the lack of dust forcing in our LGM model may lower the equivalent ECS by ~0.3°C, but this is still well above the median ECS estimate of 2.3°C in (1).

Fyke and Eby’s revised LGM-derived ECS was quite similar to other LGM-based studies, such as Holden, et al. (2010). Criticism that the UVic model used had an atmospheric component that was perhaps insufficient to fully capture the climate state at the LGM was echoed in the RealClimate discussion as well as by coauthor Nate Urban in our interview.

Schmittner, et al. (2012) responded to Fyke and Eby by largely disagreeing with their discarding of some proxy records, but conceding that their model choice may well have led to underestimating ECS and uncertainty in their reconstruction:

This tentatively supports the conclusion in (1) that structural model uncertainties (in particular, formulations of atmospheric heat transport) may have led to systematic underestimation of ECS2xC in (2). Further study with new ensemble model experiments, including the modified heat flux formulation and LGM dust forcing, are necessary to quantify the effect of heat flux uncertainties on the best ECS2xC estimate.

Schmittner, et al. go on to suggest that further modeling be done to try to better test the effects of using more realistic models with their approach.

Several groups are doing that, or something very similar. One is Tamsin Edwards, who has teased her experiment but not revealed its results (yet). Another is Jules Hargreaves and James Annan, who discussed S11 and also teased their experiment some months back but likewise did not discuss their results.

Which brings us to today (or, technically, Wednesday). Annan and Hargreaves, 2012 (hereafter AH12) has been submitted to Climate of the Past – Discussion, and their results are now available. They used almost exactly the same proxy data as S11, but used a different model (in fact, an ensemble of the GCMs used in the PMIP2 project) and methodology to constrain the difference in climate between the present and the LGM. Their results share some similarities to S11 but also contain some differences.

AH12 use pseudo-proxy data to validate their reconstruction. Their fit to the proxy data is improved relative to S11 (correlation of 0.73 vs S11′s 0.53).

Figure 5: a) Validation with GCM-Generated Pseudo-Proxy Data and b) Fit to Proxy Data

One of the criticisms of S11 was that it found an LGM globally-averaged surface temperature that seemed awfully warm (areas where proxy data were available averaged a mere~2°C colder than more modern temperatures) relative to other estimates, which show an LGM nearly three times that cold (e.g. von Deimling et al., 2006). This warmer LGM was necessarily responsible for much of the difference in their ECS value vs. the “canonical” estimate of 3°C. The authors attributed much of this difference to the use of warmer MARGO SST data vs. older (and cooler) data, but that explanation might appear somewhat insufficient, as the PMIP2 models that best fit the MARGO data themselves had ECS estimates closer to 3°C (Otto-Bliesner et al., 2009). Another odd result of S11 was the large discrepancy between their land only and ocean only results.

AH12 find an overall cooling at the LGM of ~4°C. Their land only and ocean only data are somewhat different, but are much closer than S11′s and are consistent within their uncertainties:

Figure 1: LGM Surface Air Temperature Reconstruction

Figure 2: LGM SST Reconstruction

In some ways, this represents a validation of S11: it’s certainly warmer than previous estimates, and the warm SSTs do arise from the MARGO data rather than some problem with S11. In other ways, however, it’s a contradiction of S11 and a validation of consensus estimates: the IPCC AR4′s estimate for LGM cooling was 4-7°C, consistent with AH12 but not S11.

AH12′s LGM-derived ECS is where I anticipate the greatest amount of well-meaning misunderstanding as well as outright misrepresentation. Why? Because it’s low: 1.7°C (1.2-2.4°C).

But!

One of the criticisms of S11 I raised with Nate Urban in our interview was the problem of the asymmetry of climate sensitivity during different climatic states- i.e. climate sensitivity itself may be smaller at colder times than it is during warmer times. So hypothetically a perfect estimate of equilibrium sensitivity derived from data from the LGM might be significantly lower than a perfect estimate of ECS in a doubled-CO2 future due to the non-linearity of certain feedacks. While this asymmetry is by no means an unquestionably real phenomenon, there are some very good reasons to suspect it to be true (e.g. Crucifix, 2006; Hargreaves et al., 2007; Yoshimori et al., 2011). In fact, the authors of the MARGO SST data used by S11 themselves go out of their way to warn against mistaking an LGM-derived ECS as being comparable to 2xCO2 ECS for precisely this reason (Waelbroeck et al., 2009).

AH12 note this explicitly:

However, such a simplistic estimate is far from robust, as it ignores any asymmetry or nonlinearity which is thought to exist in the response to different forcings… The ratio between temperature anomalies obtained under LGM and doubled CO2 conditions found in previous modelling studies varies from 1.3… to over 2…

Therefore, a more apples-to-apples comparison (taking into consideration the asymmetry issue) of their findings to a doubling of CO2 might look more like 2.8°C, with a range of 1.56-4.8°C.

[All I've done is apply the average of asymmetry values (1.3-2) cited by AH12 to their central value of 1.7°C, while applying the low and high end asymmetry values to their lower and upper 95% CI values respectively. This is obviously meant to be illustrative of the difference taking asymmetry into account makes for 2xCO2 vs. LGM values rather than a rigorous quantitative exploration.]

This puts the 2xCO2 ECS inline with consensus estimates such as the IPCC AR4 GCM-only estimate of 3±1.5°C. Interestingly, some of the S11 authors, using the same UVic model but with instrumental rather than LGM paleo data, found broadly similar results for ECS (Olson et al., 2012).

I’m not claiming to show what AH12 “really” says about ECS, but rather making a general point that often gets overlooked in discussions of ECS estimates derived from colder climates. And it’s certainly possible that my not-even-back-of-the-envelope extrapolation of their LGM ECS into a 2xCO2 ECS is horribly misguided for some reason that I am as of yet unaware- but I’ve inquired, and will dutifully revise this post if there is.

More than anything, this is a place-marker in the event that the typical denialist spin cranks up as it has over papers in the past.

References:

• Annan, J. D., and J. C. Hargreaves (2012), A new global reconstruction of temperature changes at the Last Glacial Maximum, Climate of the Past Discussions, 8(5), 5029–5051, doi:10.5194/cpd-8-5029-2012.
• Clark, P. U., A. S. Dyke, J. D. Shakun, A. E. Carlson, J. Clark, B. Wohlfarth, J. X. Mitrovica, S. W. Hostetler, and A. M. McCabe (2009), The Last Glacial Maximum, Science, 325(5941), 710–714, doi:10.1126/science.1172873.
• Crucifix, M. (2006), Does the Last Glacial Maximum constrain climate sensitivity?, Geophys. Res. Lett., 33(18), L18701, doi:10.1029/2006GL027137.
• Fyke, J., and M. Eby (2012), Comment on “Climate Sensitivity Estimated from Temperature Reconstructions of the Last Glacial Maximum,” Science, 337(6100), 1294–1294, doi:10.1126/science.1221371.
• Hargreaves, J. C., A. Abe-Ouchi, and J. D. Annan (2007), Linking glacial and future climates through an ensemble of GCM simulations, Clim. Past, 3(1), 77–87, doi:10.5194/cp-3-77-2007.
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Fox “News” is Beyond Parody

On the heels of what I was saying about conservative conspiracy mongering about polling data…

News Corp/Fox are beyond parody. Their own polls show the same leads they’re conspiracy theorizing about:

Via Talking Points Memo.