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Oregon Institute of Science and Malarkey

Filed under: — group @ 10 October 2007

A large number of US scientists (to our direct knowledge: engineers, biologists, computer scientists and geologists) received a package in the mail this week. The package consists of a colour preprint of a ‘new’ article by Robinson, Robinson and Soon and an exhortation to sign a petition demanding that the US not sign the Kyoto Protocol. If you get a feeling of deja vu, it is because this comes from our old friends, the Oregon Institute of Science and Medicine and is an attempt to re-invigorate the highly criticised 1999 “Oregon Petition“.

The article itself is just an update of the original article, minus an author (Baliunas), with a switch of Robinson children (Zachary’s out, Noah is in), but with a large number of similar errors and language. As in previous case, this paper too, is not peer reviewed.

Since this is a rehash of the previous paper plus a few more cherry-picked statistics of dubious relevance, instead of tediously going through the whole thing ourselves, we are going to try something new – an open source debunking.
More »

Non-condensable Cynicism in Santa Fe

Filed under: — mike @ 17 January 2017

Guest Post by Mark Boslough

The Fourth Santa Fe Conference on Global & Regional Climate Change will be held on Feb 5-10, 2017. It is the fourth in a series organized and chaired by Petr Chylek of Los Alamos National Laboratory (LANL) and takes place intervals of 5 years or thereabouts. It is sponsored this year by LANL’s Center for Earth and Space Science and co-sponsored by the American Meteorological Society. I attended the Third in the series, which was held the week of Oct 31, 2011. I reported on it here in my essay “Climate cynicism at the Santa Fe conference”.

In that report, I described my experiences and interactions with other attendees, whose opinions and scientific competence spanned the entire spectrum of possibility. Christopher Monckton represented one extreme end-member, with no scientific credibility, total denial of facts, zero acknowledgment of uncertainty in his position, and complete belief in a global conspiracy to promote a global warming fraud. At the opposite end were respected professional climate scientists at the top of their fields, such as Richard Peltier and Gerald North. Others, such as Fred Singer and Bill Gray, occupied different parts of the multi-dimensional phase space, having credentials but also having embraced denial—each for their own reasons that probably didn’t intersect.

2011 conference participants share a “Christmas in the trenches” moment on the Santa Fe plaza (author on the upper right; Monckton to his immediate left, with Singer just below)

For me, the Third Conference represented an opportunity to talk to people who held contrary opinions and who promoted factually incorrect information for reasons I did not understand. My main motivation for attending was to engage in dialogue with the contrarians and deniers, to try to understand them, and to try to get them to understand me. I came away on good terms with some (Bill Gray and I bonded over our common connection to Colorado State University, where I was an undergraduate physics student in the 1970s) but not so much with others.

I was ambitious and submitted four abstracts. I and my colleagues were pursuing uncertainty quantification for climate change in collaboration with other DOE labs. I had been collaborating on several approaches to it, including betting markets, expert elicitation, and statistical surrogate models, so I submitted an abstract for each of those methods. I had also been working with Lloyd Keigwin, a senior scientist and oceanographer at Woods Hole Oceanographic Institution and another top-of-his-field researcher. We submitted an abstract together about his paleotemperature reconstruction of Sargasso Sea surface temperature, which is probably the most widely reproduced paleoclimate time series other than the Mann et al. “Hockey Stick” graph. I had updated it with modern SST measurements, and in our abstract we pointed out that it had been misused by contrarians who had removed some of the data, replotted it, and mislabeled it to falsely claim that it was a global temperature record showing a cooling trend. The graph continues to make appearances. On March 23, 2000, ExxonMobil took out an advertisement in the New York Times claiming that global warming was “Unsettled Science”. The ad was illustrated with a doctored version of Lloyd’s graph (the inconvenient modern temperature data showing a warming trend had been removed). This drawing was very similar to one that had been generated by climate denier Art Robinson and his son for a Wall Street Journal editorial a couple months earlier. It wasn’t long before other distorted versions started showing up elsewhere, such as the Albuquerque Journal opinion page. The 2000 ExxonMobil version was just entered into the Congressional Record last week by Senator Tim Kaine during the Tillerson confirmation hearings.

Original Keigwin (1996) graph as it appeared in the journal Science.


Doctored Version of Keigwin (1996) graph that appeared in Robinson et al (1998)



Doctored version of Keigwin (1996) graph used in ExxonMobil advertisement.



In 2011, my abstracts on betting, expert elicitation, and statistical models were all accepted, and I presented them. But the abstract that Lloyd and I submitted was unilaterally rejected by Chylek who said, “This Conference is not a suitable forum for [the] type of presentations described in [the] submitted abstract. We would accept a paper that spoke to the science, the measurements, the interpretation, but not simply an attempted refutation of someone else’s assertions (especially when made in unpublished reports and blog site).” The unpublished report he spoke of was the NIPCC/Heartland Institute report, which Fred Singer was there to discuss. After the conference, I spoke to one of the co-chairs about the reasons for the rejection. He said that he hadn’t seen it and did not agree with the reasons for the rejection. He encouraged Lloyd and me to re-submit it again for the 4th conference. So we did. Lloyd sent the following slightly-revised version on January 4.

Misrepresentations of Sargasso Sea Temperatures by Global Warming Doubters

Lloyd Keigwin (Woods Hole Oceanographic Institution) and Mark Boslough (Sandia National Laboratories)

Keigwin (Science 274:1504–1508, 1996) reconstructed the SST record in the northern Sargasso Sea to document natural climate variability in recent millennia. The annual average SST proxy used δ18O in planktonic foraminifera in a radiocarbon-dated 1990 Bermuda Rise box core. Keigwin’s Fig. 4B (K4B) shows a 50-year-averaged time series along with four decades of SST measurements from Station S near Bermuda, demonstrating that at the time of publication, the Sargasso Sea was at its warmest in more than 400 years, and well above the most recent box-core temperature. Taken together, Station S and paleotemperatures suggest there was an acceleration of warming in the 20th century, though this was not an explicit conclusion of the paper. Keigwin concluded that anthropogenic warming may be superposed on a natural warming trend.

In a paper circulated with the anti-Kyoto “Oregon Petition,” Robinson et al. (“Environmental Effects of Increased Atmospheric Carbon Dioxide,” 1998) reproduced K4B but (1) omitted Station S data, (2) incorrectly stated that the time series ended in 1975, (3) conflated Sargasso Sea data with global temperature, and (4) falsely claimed that Keigwin showed global temperatures “are still a little below the average for the past 3,000 years.” Slight variations of Robinson et al. (1998) have been repeatedly published with different author rotations. Various mislabeled, improperly-drawn, and distorted versions of K4B have appeared in the Wall Street Journal, in weblogs, and even as an editorial cartoon—all supporting baseless claims that current temperatures are lower than the long term mean, and traceable to Robinson’s misrepresentation with Station S data removed. In 2007, Robinson added a fictitious 2006 temperature that is significantly lower than the measured data. This doctored version of K4B with fabricated data was reprinted in a 2008 Heartland Institute advocacy report, “Nature, Not Human Activity, Rules the Climate.”

On Jan. 9, Lloyd and I got a terse rejection from Chylek: “Not accepted. The committee finding was that the abstract did not indicate that the presentation would provide additional science that would be appropriate for the conference.”

I had also submitted an abstract with Stephen Lewandowsky and James Risbey called “Bets reveal people’s opinions on climate change and illustrate the statistics of climate change,” and a companion poster entitled “Forty years of expert opinion on global warming: 1977-2017” in which we proposed to survey the conference attendees:

Forecasts of anthropogenic global warming in the 1970s (e.g. Broecker, 1975, Charney et al., 1979) were taken seriously by policy makers. At that time, climate change was already broadly recognized within the US defense and intelligence establishments as a threat to national and global security, particularly due to climate’s effect on food production. There was uncertainty about the degree of global warming, and media-hyped speculation about global cooling confused the public. Because science-informed policy decisions needed to be made in the face of this uncertainty, the US Department of Defense funded a study in 1977 by National Defense University (NDU) called “Climate Change to the Year 2000” in which a panel of experts was surveyed. Contrary to the recent mythology of a global cooling scare in the 1970s, the NDU report (published in 1978) concluded that, “Collectively, the respondents tended to anticipate a slight global warming rather than a cooling”.

Despite the rapid global warming since 1977, this subject remains politically contentious. We propose to use our poster presentation to survey the attendees of the Fourth Santa Fe Conference on Global and Regional Climate Change and to determine how expert opinion has changed in the last 40 years.

I had attempted a similar project at the 3rd conference with my poster “Comparison of Climate Forecasts: Expert Opinions vs. Prediction Markets” in which my abstract proposed the following: “As an experiment, we will ask participants to go on the record with estimates of probability that the global temperature anomaly for calendar year 2012 will be equal to or greater than x, where x ranges in increments of 0.05 °C from 0.30 to 1.10 °C (relative to the 1951-1980 base period, and published by NASA GISS).” I included a table for participants to fill in, and even printed extra sheets to tack up on the board with my poster so I could compile them and report them later.

This idea was a spinoff of work I had presented at an unclassified session of the 2006 International Conference on Intelligence Analysis on my research in support of the US intelligence community for which a broad spectrum of opinion must be used to generate an actionable consensus with incomplete or conflicting information. That was certainly the case in Santa Fe, where there were individuals (e.g. Don Easterbrook) who were going on record with predictions of global cooling. By the last day of the conference, several individuals had filled in the table with their probabilistic predictions and I decided to leave my poster up until the end of the day, which was how long they could be displayed according to the conference program. I wanted to plug it during my oral presentation on prediction markets so that I could get more participation. Unfortunately when I returned to the display room, my poster had been removed. Hotel employees did not know where it was, and the diverse probability estimates were lost.

This year I would be more careful, as announced in my abstract. But the committee would have no part of it. On Jan 10 I got my rejection letter:

I regret to inform you that we have decided to decline this submission.

Based on our consideration of the abstract and plan, it is our view that designing a survey that accurately elicits expert opinion requires special expertise as the answers can depend on how the questions are asked. No indication of such expertise was presented in the abstract itself or found based on examination of your publication record.

A further concern dealt with the proposed comparison with opinion elicited at a different time from a different community by a different method that might allow one to “determine how expert opinion has changed in the last 40 years.”

Concern was raised also over how one might legitimately transform the results of such a poll into “into probabilistic global warming projections.”

Although we cannot accept this poster, we certainly look forward to your active participation in the Conference.

Of the hundreds of abstracts I’ve submitted, this is the only conference that’s ever rejected one. As a frequent session convener and program committee chair myself, I am accustomed to providing poster space for abstracts that I might question, misunderstand, or disagree with. It has never occurred to me to look at the publication list of a poster presenter, But if I were to do that, I would be more thorough and look other information, including their coauthors’ publication lists and CVs as well. In this case, the committee might have discovered more than a few papers by one of them on the subject, such as Risbey and Kandlikar (2002) “Expert Assessment of Uncertainties in Detection and Attribution of Climate Change” in the Bulletin of the American Meteorological Society, or that Prof. Risbey was a faculty member in Granger Morgan’s Engineering and Public Policy department at CMU for five years, a place awash in expert elicitation of climate (I sent my abstract to Prof. Morgan–who I know from my AGU uncertainty quantification days–for his opinion before submitting it to the conference).

At the very least, I would look at the previous work cited in the abstract. The committee would not have been puzzled by how to transform survey data into probabilistic projections if they had done so. They would have learned that the 1978 NDU study we cited had already established the methodology we were proposing to use. The NDU “Task I” was “To define and estimate the likelihood of changes in climate during the next 25 years…” using ten survey questions described in Chapter One (Methodology). The first survey question was on average global temperature. So the legitimacy of the method we were planning to use was established 40 years ago.

I concluded after the 3rd Santa Fe conference that cynicism was the only attribute that was shared by the minority of attendees who were deniers, contrarians, publicity-seekers, enablers, or provocateurs. I now think that cynicism has something in common with greenhouse gases. Cynicism begets cynicism, to the detriment of society. There are natural-born cynics, and if they turn the rest of us into cynics then we are their amplifiers, just like water vapor is an amplifier of carbon dioxide’s greenhouse effect. We become part of a cynical feedback loop that generates distrust in science and the scientific method. I refuse to let that happen. I might have gotten a little steamed by an unfair or inappropriate rejection, but I’ve cooled off and my induced cynicism has condensed now. I am not going to assume that everyone is a cynic just because of a couple of misguided and misinformed decisions.

As President Obama said in his farewell address, “If you’re tired of arguing with strangers on the Internet, try talking with one of them in real life.” So if you are attending the Santa Fe conference, I would like to meet with you. If you are flying into Albuquerque, where I live, drop me a line. Or meet me for a drink or dinner in Santa Fe. I can show you why Lloyd’s research really does provide additional science that is relevant to the conference. I can try to convince you that prediction markets are indeed superior to expert elicitation in their ability to forecast climate change. Maybe I can even talk you into going on record with your own probabilistic global warming forecast!

How long does it take Antarctica to notice the Northern Hemisphere is warming?

Filed under: — eric @ 29 April 2015

Eric Steig

A series of large and abrupt climate changes occurred during the last ice age, most clearly expressed in ice cores from Greenland and other paleoclimate data from the circum-North-Atlantic region. Since the discovery of these events, we’ve been trying to pin down the timing of abrupt climate changes elsewhere on the globe. Were there corresponding events in the Southern Hemisphere? And did they occur at the same time? A new paper published this week in Nature (April 30th, 2015) provide a significantly updated answer to these questions. Many in the climate research community — both modern climate and paleoclimate — will find the results quite interesting.

The new paper is the culmination of a huge effort to develop the best-dated long ice core record from Antarctica, rivaling the GISP2 and GRIP ice cores obtained from central Greenland in the early 1990s, and the more recent NGRIP and NEEM cores from North Greenland (e.g. NEEM Community Members, 2014). The core was obtained at the West Antarctic Ice Sheet divide (WAIS Divide), led by the Desert Research Institute and the University of Nevada, with the University of New Hampshire. The new paper was written by a consortium of postdocs, faculty, and students at the Oregon State University and University of Washington: Christo Buizert, myself, and Joel Pedro (now at University of Copenhagen), with Brad Markle, Ed Brook, Jeff Severinghaus and Ken Taylor. We have more than 70 other co-authors — faculty colleagues, students, postdocs, logistics coordinators, and ice-drillers — who all made substantial contributions as well. These deep ice cores are a lot of work!

We published records from the WAIS Divide ice core in 2013, covering the last two millennia and the last 30 thousand years (Steig et al., 2013, WAIS Divide Project Members, 2013). Our new work, WAIS Divide Project Members, 2015, extends the record to the bottom of the core (nearly the bottom of the ice sheet at 3400 m depth), and an age of 68 thousand years. Details on the timescale for the core are given in the open-access paper in Climate of the Past (Buizert et al., 2015). The new paper in Nature provides a comparison of the timing of changes in Antarctic temperature with the timing of the abrupt warming and cooling events that characterize the Greenland ice core records. Note that the comparison is actually made between the records of oxygen isotope ratios (δ18O), but we have very strong evidence that these track temperature quite faithfully on the relevant timescales, so I’ll use “temperature” here for simplicity.

The abrupt events in Greenland, characterized by rapid transitions from cold “stadial” to warm “interstadial” conditions and back, and commonly known as Dansgaard-Oeschger (D-O) events, were felt across the Northern Hemisphere almost immediately, as far as we can tell. But the impact of D-O events in Antarctica has been ambiguous. We’ve known for some time that temperatures in Antarctica change more slowly, and with much smaller amplitude, than in the Northern Hemisphere. In general, the Antarctic temperatures begin to decline when Greenland warms abruptly, and to increase when Greenland cools abruptly (Blunier et al., 1998). This relationship is often called the “bipolar seesaw” and is commonly attributed to the redistribution of heat between the Northern and Southern Hemispheres via changes in the Atlantic meridional overturning circulation (AMOC). We’ve also been pretty sure that each of the D-O interstadials has a corresponding warm peak in Antarctica, referred to as the “Antarctic Isotope Maximum” (AIM) events (EPICA Community Members, 2006, and Stefan Rahmstorf’s write-up in an earlier RealClimate post). But the exact phase relationship has been unknown, making it problematic to validate model simulations with confidence (see e.g. Roe and Steig, 2004, Steig, 2006).
WAIS_Divide_record

The first paper to really start to pin down the phase relationship was that of Pedro et al., 2011, who showed that the most recent of the major abrupt events in Greenland cores (the Bølling warming about 14,700 years ago and the Younger Dryas cooling about 12,880 years ago), the direction of Antarctic temperatures changed at almost exactly the same time. (Note that the Antarctic temperatures don’t change abruptly — their slow trends simply reverse sign, as shown in the figure). But the uncertainties estimated by Pedro et al. were about 200 years on either side of zero. That’s impressively good precision for something that happened more than 10,000 years ago, but not quite good enough. Our new work firms up these numbers a lot, and shows that Antarctic temperatures did not really change at the same time as the abrupt events in Greenland. Instead, when an abrupt D-O warming occurs in Greenland, it takes about 200 years until the concomitant cooling begins in Antarctica. Similarly, when an abrupt cooling occurs in Greenland, it takes about 200 years until Antarctic starts warming up. Our uncertainties are much smaller, +/-95 years*, and it is very unlikely that our numbers overlap with zero. Antarctica, in other words, almost certainly takes a century or two to notice what is happening in the Greenland.

WAIS_Divide_timing
The 200-year timescale is fascinating, because it is longer than suggested by a number of modeling studies, such as the simple “bipolar seesaw” model of Stocker and Johnson, 2003, as well as the fully-coupled transient run of a general circulation model by He et al., 2013: both show an essentially instantaneous response between the Northern Hemisphere and the Antarctic. Yet it’s also shorter than implied by many discussions of the relationship; for example, we (Steig and Alley, 2002) made the case for a 400-year lag between Greenland Antarctica, which Schmittner et al., 2003 reproduced in a climate model in which the AMOC is perturbed.

So what does the intermediate timescale of ~200 years tell us? It’s important to recognize that there are reasons why one might expect either a “fast” propagation or a “slow” propagation of the Greenland climate signal to the Antarctic. The very large sea ice changes in the North Atlantic associated with D-O events would have an impact on the atmosphere, and this should propagate global signals almost instantaneously. Indeed, this must have occurred, or we wouldn’t have the evidence that we do for abrupt changes in places as far flung as China, India, or the tropical Pacific that are in phase with Greenland temperature change. Methane variations, which are probably of tropical origin, are in phase with Greenland temperature within about 20 years (e.g., Rosen et al., 2014).

The ocean itself can propagate signals very fast, via adjustment of the upper ocean by fast Kelvin waves propagating along the ocean boundaries (e.g. Johnson and Marshall, 2002). For example, Schmittner et al. (2003), and Rind et al. (2001) both found that the North Atlantic signal in their models propagates to the South Atlantic region very quickly, appearing in subsurface waters with a time lag of only about a few decades. However, they also find a century or multi-century delay in the further southward propagation from the South Atlantic to the Antarctic across the Antarctic Circumpolar Current (ACC). Furthermore, the propagation time varies with the strength of the ACC as imposed in the model.

There are, in short, multiple parts of the ocean and atmosphere system involved, and these have different timescales. It appears that our results are right about where the physics suggests they should be. A key factor in capturing this physics properly in models seems to be how (or how well) the ACC is simulated. That’s interesting, and highly relevant to modern climate studies. How the ACC is changing now, or may change in the future, is a topic of significant interest (Fyfe and Saeko, 2005; Böning et al., 2008). And the question of how long it will take the Antarctic to catch up with the rest of the globe is of critical importance to long term projections of the response of the ice sheet to climate change — and hence the response of sea level. The D-O events and the current anthropogenic global warming are of course very different beasts, but the long timescales indicated by our results are certainly in keeping with climate model projections of the future, showing that most of Antarctic should lag the rest of the planet (recent rapid warming on the Antarctic Peninsula and West Antarctica not withstanding).

Note that our results should not be taken as demonstrating anything very specific in terms of the cause of Dansgaard-O events. To be sure, the results demonstrate a clear north-to-south direction in the propagation of the climate signal associated with abrupt D-O warming and cooling events. But that doesn’t tell us what the driving “trigger” is. To use an analogy suggested by co-author Severinghaus, suppose we didn’t know anything about the physics relating lightning to thunder. Careful measurements of their relative timing would reveal that thunder always occurs very soon (or immediately) after lightning. But hearing thunder gives you only a general prediction of when the next lightning will be observed. One would correctly deduce that lightning causes thunder. That’s progress. But it would not tell you the cause of the lightning in the first place.

For my part, I’ve long been a skeptic about the old idea that the D-O variations are ultimately driven by meltwater and/or iceberg fluxes into the North Atlantic (the Day after Tomorrow scenario, if you will). There are only 6 clearly-identified Heinrich events (that is, layers of terrestrial sediment in ocean sediment cores from the North Atlantic, evidence for massive iceberg discharges from the Laurentide ice sheet) but there are at least 23 D-O events. It more likely that there is intrinsic variability in the coupled ocean-atmosphere system, as found for example in a long simulation with the climate model CCSM4 by Peltier and Vettoretti (2014 and 2015) (though there is debate about the validity of the very low values for ocean vertical mixing used in those simulations). Iceberg discharges are then just the consequence, not the cause, of changes in ocean circulation, as argued recently by Alvarez Solaz et al. (2013) and also suggested by Barker et al. (2015) who found that on average, evidence for icebergs in the North Atlantic follow, rather than precede, the abrupt coolings at the end of some D-O events. That doesn’t mean that the huge ice and meltwater fluxes associated with Heinrich events don’t have an impact; most modeling work suggests that they would. But it may be important in this context that our results show no dependence of the ~200-year lag on whether or not a Heinrich event has occurred: that is, there is no evidence that “Heinrich stadials” (the cold periods during which Heinrich events occur) are unusual with respect to ocean “seesaw” dynamics. The role of these events in millennial scale variability therefore remains an important, and open, research question (see e.g., Margari et al., 2010).

In the meantime our precise observations of the phasing of D-O and AIM events provide an important new constraint against which to validate model simulations designed to capture the dynamics of these interesting features of the climate system.

UPDATE: The News & Views article about our article, by Tas van Ommen is worth a read. Available here (subscription based only, I’m afraid).



Notes. *The ability to obtain such small uncertainties is owing to four main things. First, we have very high resolution measurements of methane in both the WAIS Divide and the Greenland cores; methane is globally well mixed, and so abrupt changes in methane must happen at the same time (within a year) in cores from both regions. This means that we can synchronize the age of the gas trapped in the bubbles within the cores very precisely. Second, we have very high resolution measurements of the nitrogen isotope ratio (15N/14N in atmospheric N2), also trapped in the bubbles in the cores. This isotope ratio provides information on the age difference between the gas and the ice, because gravitational settling increases the 15N/14N ratio; this depends on the thickness of the firn (the permeable ice between the surface and the impermeable ice at depth where bubbles are trapped). The deeper the firn, the longer it takes to trap gases, and the larger the age difference. It’s the age of the ice that we’re actually interested in, because this, not the gas trapped within the ice, is what the δ18O measurements are made on. Fourth, this age difference is much smaller at WAIS Divide than in any other long Antarctic record; it is at most ~500 years, compared with e.g., ~4000 years at Vostok. Finally, we also have unprecedentedly high resolution measurements of δ18O, and very high quality borehole temperature measurements, which together provide a very robust measure of the temperature variations through time.

Data: The data from the paper are all available in the Supplement to the paper. The timescale and the oxygen isotope data from our lab — what most people will be interested in — are available at the National Snow and Ice Data Center, at doi:10.7265/N5GT5K41.

References:

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Climate cynicism at the Santa Fe conference

Filed under: — group @ 19 December 2011

Guest commentary by Mark Boslough*

The Third Santa Fe Conference on Global and Regional Climate Change was held during Halloween week. It was most notable for the breadth of opinion — and the span of credibility — of its speakers. I have long complained about the lack of willingness of most contrarians to attend and present their arguments at mainstream scientific conferences. After three years of convening climate-related sessions at AGU, I have yet to receive an abstract that argues against anthropogenic global warming. Such presentations can usually only be seen at conferences held by the Heartland Institute. There isn’t much chance of a mainstream scientist attending a meeting organized by a political think tank known for its anti-science activism, so opportunities for interaction between the groups are rare.
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Not the IPCC (“NIPCC”) Report

Filed under: — mike @ 28 November 2008 - (Italian)

Michael Mann and Gavin Schmidt

Much in the spirit of the Fraser Institute’s damp squib we reported on last year, S. Fred Singer and his merry band of contrarian luminaries (financed by the notorious “Heartland Institute” we’ve commented on previously) served up a similarly dishonest ‘assessment’ of the science of climate change earlier this year in the form of what they call the “NIPCC” report (the “N” presumably standing for ‘not the’ or ‘nonsense’). This seems to be making the rounds again as Singer and Heartland are gearing up for a reprise of last year’s critically…er…appraised “Conference on Climate Change” this March. Recently some have asked us for our opinion of the report and so we’ve decided we ought to finally go ahead and opine. Here goes.

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Les Chevaliers de l’Ordre de la Terre Plate, Part II: Courtillot’s Geomagnetic Excursion

Filed under: — raypierre @ 18 December 2007 - (Français)

This article continues the critique of writings on climate change by Allègre and Courtillot, started in Part I . If you would like to read either post in French, please click on the flag icon beside the post title above.

Prelude: It’s the physics, stupid

…which of course is a paraphrase of Bill Clinton’s famous quote regarding the economy. We put the last word in small letters since we’ve learned that it is not a good debating technique to imply (even inadvertently) that those who are having trouble seeing the force of our arguments might be stupid. What we wish to emphasize by this paraphrase is the simple fact that the expectation of a causal link between increasing long-lived greenhouse gases (like CO2) and increasing temperature does not rest on some vague, unexplained correlation between 20th century temperature and 20th century greenhouse gas concentration.

The anticipated increase in temperature was predicted long before it was detectable in the atmosphere, indeed long before it was known that atmospheric CO2 really was increasing; it was first predicted by Arrhenius in 1896 using extremely simple radiation balance ideas, and was reproduced using modern radiation physics by Manabe and co-workers in the 1960’s. Neither of these predictions rests on general circulation models, which came in during subsequent decades and made more detailed forecasts possible.

Still, the basic prediction of warming is founded on very fundamental physical principles relating to infrared absorption by greenhouse gases, theory of blackbody radiation, and atmospheric moist thermodynamics. All these individual elements have been verified to high accuracy in laboratory experiments and field observations. For a time, there was some remaining uncertainty about whether water vapor feedback would amplify warming in the way hypothesized in the early energy balance models, but a decade or two of additional observational and theoretical work has shown that there is no real reason to doubt the way in which general circulation models calculate the feedback. When modified by inclusion of the cooling effect of anthropogenic aerosols, the theory gives a satisfactory account of the pattern of 20th and 21st century temperature change.

No other theory based on quantified physical principles has been able to do the same. If somebody comes along and has the bright idea that, say, global warming is caused by phlogiston raining down from the Moon, that does not make everything we know about thermodynamics, infrared absorption, energy balance, and temperature suddenly go away. Rather, it is the job of the phlogiston advocate to quantify the effects of phlogiston on energy balance, and incorporate them in a consistent way beside the existing climate forcings. Virtually all of the attempts to poke holes in the anthropogenic greenhouse theory lose sight of this simple and unassailable principle.

In a paper entitled "Are there connections between the Earth’s magnetic field and climate?" published recently in Earth and Planetary Science Letters, Courtillot and co-authors attempt to cast doubt on carbon dioxide as a primary driver of recent (and presumably future) climate change; he argues instead that fluctuations in the Earth’s magnetic field (partly driven by solar variability) have an important and neglected role. Like most work of this genre, it is carried out in an intellectual void — as if everything we know currently about physics of climate had to be set aside in order to make way for one new (or in fact not-so-new) idea. But the problems don’t end there. With the help of a Comment published by Bard and Delaygue (available here at EPSL or here as pdf) , we’ll expose a pattern of suspicious errors and omissions that pervades Courtillot’s paper. Sloppiness and ignorance is by far the most charitable interpretation that can be placed on this pattern.

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