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« Political science | Main | Not his finest hour - Josh 106 »

Reliable sources

Scibloggers are all tweeting furiously about this article on the Skeptoid blog. It's a pretty interesting piece, which argues that sceptics should follow the data and warmists should be nicer. There's much to agree with, but the author Craig Good rather shoots himself in the foot by repeated recommending Skeptical Science as an unbiased source on the subject of global warming.

As I have pointed out in the past, Skeptical Science's reporting of some issues I am familiar with are deeply troubling. It is hard to credit the site's failure to even mention that the Hide the Decline dataset had been truncated or to cover the troubled Cook et al divergence problem paper from 2004, but not the more up to date D'Arrigo et al study.

But hey, perhaps this is a one-off oversight. Maybe things are more balanced elsewhere in the Skeptical Science oeuvre. With this in mind, I went to have a look at the temperature records - thinking to see how the the subject of statistical significance was handled. I didn't find anything on a brief search but got distracted by this bit about urban heat islands - the bit of the observed warming that is due to waste heat from human settlements rather than climatic change.

[NASA/GISS] found in most cases, urban warming was small and fell within uncertainty ranges. Surprisingly, 42% of city trends are cooler relative to their country surroundings as weather stations are often sited in cool islands (a park within the city).

Now again, this is something I am reasonably familiar with. The claim comes from a paper by Peterson et al 2003 - having found that many urban stations warmed less than rural ones, they rationalised this by hypothesising that urban stations were in cool parks:

But do the urban meteorological observing stations tend to be located in parks or gardens? The official National Weather Service guidelines for nonairport stations state that an observing shelter should be ‘‘no closer that four times the height of any obstruction (tree, fence, building, etc.)’’ and ‘‘it should be at least 100 feet from any paved or concrete surface’’ (Observing Systems Branch 1989). If a station meets these guidelines or even if any attempt to come close to these guidelines was made, it is clear that a station would be far more likely to be located in a park cool island than an industrial hot spot.

And that's it. But, as we know, Anthony Watts has surveyed US weather stations and found that they are not even close to being compliant with the guidelines, a finding which makes a mockery of the claims in the Peterson paper, even leaving aside some of the other problems with the paper.

Don't get me wrong here. I doubt very much whether a properly calculated UHI correction would make a significant difference to the warming trend observed in recent decades. My point is not that you can pin a large number of the size of the UHI effect, but that you can pin quite a small one on the reliability of Skeptical Science.

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Reader Comments (86)

When you compared two sets of data to argue that the land data was similar to the satellite data and therefore the land data must be alright, BBD, wasn't there some 'data' that we discussed and argued about?

What is Craig Good doing?

Jun 20, 2011 at 2:20 AM | Unregistered CommenterShub

For what its worth, the consensus at today was that is less than educational.

In my humble opinion, the matter of UHI is yet another example of the Warmista undertaking research designed to support their assumption that there is none. Jones' studies were in a Chinese mountain town and in London. Give me a break. London has no sunlight and no heat, so how can it have UHI? Do a study in a city noted for UHI, such as St. Louis, Missouri. Researchers will find that the temperature difference between the old city and the distant suburbs, not the old suburbs, is about ten degrees Farenheit in July and August and maybe six degrees in January and February.

Jun 20, 2011 at 3:30 AM | Unregistered CommenterTheo Goodwin

John Cook of Skeptical Science was in a former life a full time cartoonist.

This is probably something that we should embrace as most of us are fans of Josh's creations, (not to mention the wonderful Fenbeagle)

Maybe we should scrap the boring old peer review system and hand the joysticks to the children to fight this out in playstation-land?

Jun 20, 2011 at 8:57 AM | Unregistered Commenterandyscrase

I thought urban heat was well established?

"Hot town, summer in the city
Back of my neck gettin' dirt-'n'-gritty
Bend down, isn't it a pity
Doesn't seem to be a shadow in the city
All around people lookin' half dead
Walking on the sidewalk, hotter than a match-head"

(John Sebastian - 1966)

Jun 20, 2011 at 9:05 AM | Unregistered CommenterJames P


John Cook's main site appears to make no mention of SS, despite links to everything else he does. A case of mild embarrassment, perhaps?

His wife seems to be quite talented.

Jun 20, 2011 at 9:19 AM | Unregistered CommenterJames P


Now you are posting as phil listine. At some point, your persistent use of multiple pseudonyms and unpleasant rhetoric will get you banned.

Jun 20, 2011 at 9:19 AM | Unregistered CommenterBBD

not banned yet

- radiative physics

- no other phenomena demonstrably responisble for post-1950 warming

- absence of any credible null hypothesis explaining why increasing conc of atmospheric CO2 will NOT trap more energy in climate system

- Arctic ice loss affecting ice sheets stable for past several ky (see Polyakov et al. 2010)

Jun 20, 2011 at 9:24 AM | Unregistered CommenterBBD


You can carry on believing whatever makes you happy. I think Kloor had it about right.

Jun 20, 2011 at 9:25 AM | Unregistered CommenterBBD


What is Craig Good doing?

Talking SENSE.

What are you doing?

Jun 20, 2011 at 9:26 AM | Unregistered CommenterBBD


let her explain what she thinks of 10:10, Al Gore's inconvenient truths, and of UHI 's skewering of the data.

- 10:10 = appalling

- AG = silly

- UHI = surface boundary layer effect, energetically insignificant, not relevant to discussion of GATA increase. See good agreement between surface trend (GATA) and RSS/UAH TLT. Think about it.

Jun 20, 2011 at 10:34 AM | Unregistered CommenterBBD

The one good thing about skepticalscience is that it does attract the weaker-minded/lazy/conformism-prone/bourgeois/uninformed "skeptics".

Like reading "The Economist", it's a stage in one's life. Some people though, never graduate from that stage.

Jun 20, 2011 at 10:52 AM | Unregistered CommenterMaurizio Morabito

BBD - In know you are a discerning sceptic and always read your comments with interest (but don't necessarily agree with everything you say - e.g. I don't think the post 1950's is historically significant or anything to worry about even if it is, and I don't think there's any reliable evidence for CO2 being responsible) but what do you think of the possibility that there's good agreement between RSS/UAH and surface station GATA because the satellite sensors (or rather the data processing algorithms) were calibrated using UHI contaminated data, or just flawed assumptions? (I am not saying that RSS/UAH data is not accurate or reliable, just that it may not be as bomb proof as many believe. There was a discussion of this concern on WUWT a couple of years ago by two satellite sensor techies, and if I could find the link I would post it).

Jun 20, 2011 at 12:56 PM | Unregistered Commenterlapogus

BBD, You asked me why I thought Craig Good's article was weak, and I gave you reasons. In response, you are saying: "you can believe whatever you want".

I do think that Good's article was like a breath of fresh air, in some respects. I am however, not so much in need of such affirmation.

In other news, I just came across this article in Desmogblog. It begins like this:

The great Australian blog SkepticalScience has launched an Interactive History of Climate ...

Jun 20, 2011 at 1:19 PM | Unregistered CommenterShub


Spencer says somewhere on his blog that the calibration of the sensors on the satellite is done absolutely independently of earth-bound instruments. If he says that, it's good enough for me.

The fact is (and not everyone likes it, but it's still a fact) that the agreement in trend between UAH/RSS TLT and surface GATA is clear and obvious proof that UHI is a non-issue.

Jun 20, 2011 at 7:20 PM | Unregistered CommenterBBD


BBD, You asked me why I thought Craig Good's article was weak, and I gave you reasons.

Not really. Your comments came across as a miasma of delegitimisation with no critical hooks into the text itself.

Jun 20, 2011 at 7:25 PM | Unregistered CommenterBBD


Sorry to be vague earlier. The explanation of how satellite temperature measurements work is here:

Jun 20, 2011 at 8:22 PM | Unregistered CommenterBBD

Mr. King wants us to know that sceptical science is backed up by real peer-reviewed published science by "experts". I prefer science performed in accordance with the scientific method. Using data from instruments sited in accordance with scientific standards. And databases employing a bit of quality control. Relying on models which have met minimum requirements of verification and validation.

Jun 20, 2011 at 8:28 PM | Unregistered Commenterstan

What is the matter, my friend? Look at my posts explaining why I think Good's article is, on the whole, no good. They carry a central line of argument and are substantive (compared to your two-three word pronouncements).

You came with the reverse psychology analysis of my posts. You dont have to do that. If I want to smear Good in association with Dunning, I will do that directly. My post about Dunning might have appeared below yours, but I was not responding to you.

The argument, you inferred, was at the heart of the article was this sentence:

Are you willing to follow the data? Good, because if nothing can convince you to change your mind, your mind is closed.

Unfortunately, as we know, the argument is not as simple as this cliche. "Data" alone does not lead to scientific conclusions - there are assumptions, a level of prior understanding, and a hypothesis framed to answer certain questions, and only then does the 'data' start making any sense.

Good does not go into any of these. Instead, he only displays a basic scholarly ability to be led by the nose as swallowed frames wholesale and became 'convinced'. Is he worth following?

The short answer is: no. Craig Good does not know what he is talking about. This is the same point put across by omnologos, and Jake Haye above. This is the same point I made when I talking about precis'ing his article. All these nice and goody-goody stuff about advice he gives to his lefty friends evaporates. And the remonstrations to his right-wing friends do too.

"Follow the data" - to his rightie friends? So in Good's view, right-wing people don't follow the data? and left-wing people do? Good also says "That amount of politicization brings corrupting quantities of money". This is upside-down. The corrupting quantities of money brings politicization. Good has cause- and effect reversed here.

So, someone who is 'convinced' by, gets bowled over by Peter Gleick, and spouts political cliches does not deserve all this analysis in the first place. He doesn't deserve 'delegitimization'.

On the other hand when I laid out my reasons, it was your responses, that contained miasmatous utterings about Keith Kloor (?).

Jun 20, 2011 at 10:03 PM | Unregistered CommenterShub


"Data" alone does not lead to scientific conclusions - there are assumptions, a level of prior understanding, and a hypothesis framed to answer certain questions, and only then does the 'data' start making any sense.

Absolutely. So when Polyakov shows the unusual (on a millennial scale) ice loss in the Arctic, and the Iceman Emergeth... well, I look for reasons.

None of the above means that MBH98 and MBH99 weren't calculated attempts to misrepresent paleoclimate. I think most equal opportunities sceptics would agree on that.

Remember that when the iceman died, the aftermath of the Holocene Thermal Maximum was still running the show.

Polyak et al. 2010, History of sea ice in the Arctic, Quaternary Science Reviews 29 (2010) 1757–1778

Grosjean, M., Suter, P. J., Trachsel, M. and Wanner, H. 2007. Ice-borne prehistoric finds in the Swiss Alps reflect Holocene glacier fluctuations. J. Quaternary Sci.,
Vol. 22 pp. 203–207. ISSN 0267-8179.

Jun 20, 2011 at 10:23 PM | Unregistered CommenterBBD

Oh dear. 'Polyak'.

Jun 20, 2011 at 10:25 PM | Unregistered CommenterBBD


I read that paper and I have to say that it left me singularly unimpressed. For instance, they explain how they arrived at their conclusions using a combination of various sediment and ice core analysis. They then go on to explain how basically unsuitable each of those very same proxies are for the kind of study they are attempting, but then go on to state that by combining all these different proxies (in some special, magic way, no doubt) they can still arrive at their confident conclusions anyway. Yeah. Right. Nonetheless, I ploughed on through it and came out the other end feeling a bit confused and more than a little unconvinced. My own simple-minded, uneducated and illiterate conclusion was that they were over-reaching at best. It was only then, after reading it, that I looked at the author list and things became clearer.

I am too tired right now to go searching for the references (it's been a long, busy day at work), but there are plenty of eye-witness accounts going back 150 years or more that suggest the summer ice melts we are seeing right now are nothing particularly unusual. It should also be remembered that one of the triggers for the coming ice-age scare of the 70s was the alarm some scientists felt over how the Arctic ice pack was growing, thereby suggesting that when satellite measurement started, there was actually more ice than usual anyway.

Jun 21, 2011 at 1:11 AM | Unregistered CommenterLC

Sorry, I should have made it clear, it's the Polyakov paper I'm refering to. Said I was tired....

Jun 21, 2011 at 1:16 AM | Unregistered CommenterLC

Good grief, now I'm doing it. POLYAK. Go to bed man....

Jun 21, 2011 at 1:19 AM | Unregistered CommenterLC

BBD - thanks for the link to Spencer's summary. Irrc the the techies' key concern was with the post-processing algorithms (i.e. how could they be so sure that the detected infra-red signal was from the target level in the troposphere but Roy appears to have everything well nailed down and Christie has been cross-checking the results with radiosonde data so agree that it all looks reliable. They even seem confident that the potential error of 1C can be adjusted for accurately, each time the data is sourced from a different satellite. That said I also agree with Roy's dispassionate summary of the situation wrt CO2's climate sensitivity, and the chaotic influences the PDO is having over cloud cover and the amount of solar radiation that reaches the oceans and land. I note he also leaves the door ajar for Svensmark.

Jun 21, 2011 at 8:17 AM | Unregistered Commenterlapogus

BBD - I have not had time to look up the Polyakov paper but from reading LC's take on it does sound like they were clutching at straws. I certainly agree with LC wrt to the many accounts of open waters in the high arctic - there was a book published on the web last year which detailed accounts from the early whaling ships (17th and 18th C), some of which got much further north than Nansen's late 19th century expedition in the Fram. (iirc a few claimed to have got 85 degrees north and one 88). Again, sadly I don't think I saved the link, or if I did I am not sure which laptop. I'll try to find it.

Jun 21, 2011 at 8:35 AM | Unregistered Commenterlapogus

LC and Lapogus

Sorry about the ‘Polyakov’ meme. It’s definitely catching.

I do not agree with LC’s critique of the Polyak study. It sounds more to me like a combination of not liking what it says and a knee-jerk reaction to the fact that Serreze is one of the co-authors. But so was Alley. Prof.GISP himself. And Polyak is highly respected. You want pedigree, you have it.

Issues over proxies and the historical extent of summer sea ice melt aside, you do not address the key finding, namely the break-up of the ice sheets off Ellesmere island. Now that needs a better explanation than ‘natural variability’ since nature clearly hasn’t varied enough to melt them since the cooling following the Holocene Thermal Maximum (HTM).

So what’s going on now?

The composite historical record of Arctic ice margins shows a general retreat of seasonal ice since about 1900, and accelerated retreat of both seasonal and annual ice during the last five decades (Fig. 2a). The most reliable observations are from 1979 onwards, corresponding to the modern satellite era. Patterns of ice-margin retreat may differ between different periods and regions of the Arctic, but the overall retreat trend is clearly larger than decadal-scale variability, consistent with observations and modeling of the 20th-century ice concentrations and water temperatures. The severity of present ice loss can be highlighted by the breakup of ice shelves at the northern coast of Ellesmere Island, which have been stable until recently for at least several thousand years based on geological data. On the basis of satellite records, negative trends in sea-ice extent encompass all months, with the strongest trend in September. As assessed by the U.S. National Snow and Ice Data Center, the September trend over the period 1979–2009 is 11% per decade. Conditions in 2007 serve as an exclamation point on this ice loss. The average September ice extent in 2007 of 4.28 million km2 was the lowest in the satellite record and 23% lower than the previous September 2005 record low of 5.56 million km2. On the basis of an extended sea-ice record, it appears that the September 2007 ice extent is only half of that estimated for the period 1950–1970 based on the Hadley Center sea ice and sea-surface temperature data set (HadlSST)). While the ice extent rebounded slightly in September 2008 and 2009, these months rank second and third lowest in the satellite record, respectively.

[Emphasis added.]

Then we have this, from the World Glacier Monitoring Service 5th Report:

Mass balance measurements on entire glaciers have been available for the past six decades. Glacier mass change is a direct, undelayed reaction to atmospheric conditions. The specific mass balance can be compared directly between different glaciers. This makes it easier to establish a link to climate data, as compared to length changes. However, the limited number of long term observations – only 30 ‘reference’ glaciers have continuous data series since 1976 – renders global analysis much more complicated.

As a consequence there are three main approaches to calculating global average mass balances which are independent of climate, hydrology or climate indicator data. These are by (i) using the (arithmetic) mean value of the few continuous measurement series, (ii) averaging the moving sample of all available data series, and (iii) using regionally weighted samples (cf. Kaser et al. 2006). However, when cumulated over the past six decades, the results of these approaches are consistent.

The global averages (i, ii, iii) reveal strong ice losses in the first decade after the start of the measurements in 1946, slowing down in the second decade (1956–65), followed by a moderate mass loss between 1966 and 1985, and a subsequent acceleration of ice loss until present (Fig. 5.8 a—f). The mean of the 30 continuous ‘reference’ series yields an annual mass loss of 0.58 m water equivalent (m w.e.) for the decade 1996–2005, which is more than twice the loss rate of the previous decade (1986–95: 0.25 m w.e.), and over four times the rate for the period 1976–85 (0.14 m w.e.).

Overall, the cumulative average ice loss over the past six decades exceeds 20 m w.e. (Fig. 5.9), which is a dramatic ice wasting when compared to the global average ice thickness, which is estimated (by dividing estimated volume by area) to be between 100 m (IPCC 2007) and about 180 m (Ohmura, personal comm.).

The average ice loss over that period of about 0.35 m w.e. per year exceeds the loss rates reconstructed from worldwide cumulative length changes for the time since the LIA (see Hoelzle et al. 2003) and is of the same order of magnitude as characteristic longterm mass changes during the past 2 000 years in the Alps (Haeberli and Holzhauser 2003).

From the same report, here’s a picture worth a thousand words showing the change in glacier length ca 1885 – 2005. Here are the same length change observations compared to mass balance change.

Which brings us back to the Iceman. Nobody has commented on the Grosjean paper I referenced earlier, which is surprising as it illustrates the above with particular clarity.

Why did ice that has protected leather, wood, fabric and human remains for five thousand years recently melt? That ice formed after the HTM but when the NH climate was still unusually warm (on a millennial scale). The unavoidable implication is that Schnidejoch ice melt is (gasp) unprecedented in 5ky.

I ask again: what’s going on?

From the abstract (emphasis added):

During the hot summer of 2003, reduction of an ice field in the Swiss Alps (Schnidejoch) uncovered spectacular archaeological hunting gear, fur, leather and woollen clothing and tools from four distinct windows of time: Neolithic Age (4900 to 4450 cal. yr BP), early Bronze Age (4100–3650 cal. yr BP), Roman Age (1st–3rd century AD), and Medieval times (8–9th century AD and 14–15th century AD). Transalpine routes connecting northern Italy with the northern Alps during these slots is consistent with late Holocene maximum glacier retreat. The age cohorts of the artefacts are separated which is indicative of glacier advances when the route was difficult and not used for transit. The preservation of Neolithic leather indicates permanent ice cover at that site from ca. 4900 cal. yr BP until AD 2003, implying that the ice cover was smaller in 2003 than at any time during the last 5000 years. Current glacier retreat is unprecedented since at least that time. This is highly significant regarding the interpretation of the recent warming and the rapid loss of ice in the Alps.

Jun 21, 2011 at 12:26 PM | Unregistered CommenterBBD

Well, BBD, you do seem to take your mindreader duties quite seriously. Also apart from that, it is difficult to understand why you've launched into a discussion of Polyak

I just stumbled upon another thing more relevant to our original discussion - the word: irenic. Apparently, 'irenic' is the opposite of 'polemic', defined as "favoring, conducive to, or operating toward peace, moderation or conciliation". As Brian Cox casually smuggled through his description of The Great Global Warming Swindle as 'polemical cack' in his BBC programme, it is more appropriate to describe Craig Good's piece as irenical cack.

Incidentally I realized that Keith Kloor and Judith Curry both started off as irenics. Peaceful, serene, smiling, working sincerely towards reconciliation, and in the case of Kloor with a bit of disdain and pity toward skeptics like Watts (easy to feel pity for deinstitutionalized orphans). I'm sure they've both got a bit of the 'bloodied nose' by now, though I'm again leaning to think that Kloor probably still thinks himself above the fray.

To the Goods and the Kloor: the only way to be in a fight is to get in yourself. If you come close to the tumbling roiling mob, all pious and arms raised in peace saying: "now, now, come on guys", it is sooner than later that someone's going to clock you.

Jun 21, 2011 at 6:52 PM | Unregistered CommenterShub


Trying to delegitimise me again with the quip about 'mindreader duties' I see.

You were the one pontificating about how we understand data etc. I simply provided a set of examples which take data and raise interesting questions. Which you ignored.

Jun 21, 2011 at 7:35 PM | Unregistered CommenterBBD

Ignoring the data was what Good argues the 'sceptics' do. Hence the relevance. Sorry if it got too complicated for you.

Jun 21, 2011 at 8:07 PM | Unregistered CommenterBBD

Just because I criticized you does not mean I am trying to 'delegitimize'.

Look at what you wrote to LC: "...sounds more to me like a combination of not liking what it says and a knee-jerk reaction to the fact that Serreze is one of the co-authors...". Where did you get that from? LC doesn't talk about Serreze.

Moreover, if you don't take well to someone characterizing (what you think are) your substantive objections as mere argument techniques, then the same applies to those you are discussing matters with. That, however, is what you seem to do quite a bit.

My point about 'data', again, was and is no pontification. It is an easily-understood facet of rhetoric. It is an easy stance to just point to findings from some or the other study, declare that to be 'data' and then call those who want to ask more than just superficial questions, to be unwilling to be moved by 'data'. The warmists do this all the time. Good's approach is no different.

Again and moreover, why would you present data and raise interesting questions? I pointed out Good did not do so. You cannot compensate for him. I would discuss Polyak when I get to finish reading the papers you suggested.

Jun 21, 2011 at 8:41 PM | Unregistered CommenterShub


Just because I criticized you does not mean I am trying to 'delegitimize'.

Really? Then you should choose your words more carefully.

Where did you get that from? LC doesn't talk about Serreze.

LC said:

It was only then, after reading it, that I looked at the author list and things became clearer.

So who do you think he was talking about? This sort of thing is tedious btw.

Moreover, if you don't take well to someone characterizing (what you think are) your substantive objections as mere argument techniques, then the same applies to those you are discussing matters with. That, however, is what you seem to do quite a bit.

I try to make reasoned and supported arguments. When responses appear to be illogical or unsupported, I question them. As one does.

Again and moreover, why would you present data and raise interesting questions? I pointed out Good did not do so. You cannot compensate for him.

I do not see what failings Good's piece has that require me to 'compensate for him'. I appreciate that you do, but do not agree with your critique of his article. But we've been through that.

Enjoy the paleoclimate stuff.

Jun 21, 2011 at 8:56 PM | Unregistered CommenterBBD

Well, when I read LC's comment, what I got was that he read the article, was left unimpressed and then, looked at the author list and went Ah!. You seemed to suggest the other way around.

If my critique of the Good article did not strike a chord, then I have obviously failed. I'll try to do a better job next time. I think there will be more opportunities to go around.

Jun 22, 2011 at 2:41 AM | Unregistered CommenterShub


Deafening silence on the question posed by the various cryosphere studies I see.

Jun 22, 2011 at 1:46 PM | Unregistered CommenterBBD


First off, lets get something straight so we both know where we stand. Over the last 5 or 6 years, I have gone from “believer” to “lukewarmer” to the position I hold now, that of just about “lukewarmer” but not quite outright “denier“. I constantly review my position and put a great deal of examination into my own prejudices to make sure that I’m not falling into the trap of confirmation bias. Yes, I occasionally make “knee-jerk” assumptions as we are all wont to do. But I try very hard not to. I consider myself to be a true sceptic. Whenever I read a new paper, I do my level best to read it with an open mind, whoever it comes from. Not being a scientist and having no formal training, I have to rely on my own sense of logic and the experience built up from 56 years of living in the real world (see Jeff Id‘s Air Vent thread for my story). This obviously means that some of the technical stuff and some of the nuances will go over my head, so my conclusions drawn on any paper will necessarily be subjective. Accordingly, I will get things wrong, I’m sure I often do.

However, you brought the subject of the paper up. So I read it. I then gave you my impressions. You, despite me giving some of the reasons why I wasn’t impressed with the paper, then do exactly what you accused Shub of doing to you and “try to delegitimize” me by claiming my views were a “knee- jerk” reaction. Now, whether you like it or not, when I said that I looked at the author list after reading the paper, that’s exactly what happened. When I did look at the list, it wasn’t just Serreze that that jumped out at me. I do not share your views on Alley and Wolff has had some very questionable things to say too. I do not doubt for one moment that these are all very good scientists, if only they could stop with the silly alarmism and concentrate on giving us good science. As for the paper itself, it seemed more suited as a discussion paper and more a collation of other peoples work with some questionable conclusions drawn, rather than new work. Not only did they fail to adequately explain how linking together a series of records and proxies that they readily admitted were unsuitable in themselves for what they were trying to do, but they gave no proper indication of the uncertainty levels in doing so. Then there are the proxies themselves. For instance they use the historical Icelandic sea-ice records and claim good correlation between temps and sea-ice levels. They give us a short graph (Fig.5) which only runs for 30 years (1820-1850). Yet, though there is reasonable correlation for the first 20 years in that graph, I’m not sure one could say the same about the last ten years when temps were up and down yet ice cover remained fairly constant. Later in the paper, they give us Fig.12, a comparison between a multi-proxy reconstruction of sea-ice cover in the Nordic Seas and another reconstruction of arctic-wide sea-ice cover. In this one, they claim correlation apart from the early 20th century. To my lying eyes, there doesn’t appear to be much in the way of any correlation at all! Incidentally, that reconstruction of the Nordic Seas ice cover shows similar low levels in the mid 17th century and the early 20th century. Of course, one also has to give the benefit of the doubt that the various reconstructions and papers they reference are themselves correct in the first place. There are other issues, in my view, with the paper, but this comment is long enough already. Suffice to say, I do not feel they prove their case that up till now, the Arctic has remained at near constant for the last 5 thousand years. That there is undoubtedly something going on up there cannot be argued, but I do not believe we are anywhere near knowing enough to accurately determine whether it is particularly unusual or what it is that’s causing it. Just because we can’t think of anything other than the CO2 we are adding to the atmosphere, doesn’t mean it is. With regard to the paper you mention on glaciers, I haven’t had time to read it yet, but I certainly will at some point.

Jun 22, 2011 at 4:29 PM | Unregistered CommenterLC


Always nice to talk to another true sceptic and lukewarmer. A few things:

- You made the remark about it 'all becoming clear' when you read the author list. I stand by my observation that this was an illogical 'knee-jerk' negative response. You freely admit to Serreze being part of the 'problem', and helpfully add Alley and Wolff to the list of researchers you do not 'like'.

- Polyak et al. 2010 is a review paper. Not 'new work' as such.

- It's fine to question the methodology as you do. What's not fine is to dismiss the breakup of the ice off Ellesmere Island as if it were invalidated by doubts about the use of proxies.

Just because we can’t think of anything other than the CO2 we are adding to the atmosphere, doesn’t mean it is.

It doesn't mean it isn't, either. To argue that you would need a null hypothesis that explains why, despite all we know about the physical properties of CO2, adding more of it to the atmosphere would NOT increase the amount of energy in the climate system.

Now, considered like that, which seems more likely? You said you were a lukewarmer, so presumably you agree that the increased radiative forcing is the main reason for recent warming (since there's no other apparent explanation).

The real argument must therefore be about climate sensitivity. Not attribution. Logically there isn't anywhere else to go.

Jun 22, 2011 at 5:19 PM | Unregistered CommenterBBD


Sorry for the late reply, been away again. As this thread has now pretty much come to an end, I'll make this my last comment on this for now.

Firstly, my actual words were "all became clearer". That's clear-ER. It's not the case that there are scientists I don't "like". Please don't put words in my mouth. There are, however, scientists on both sides of the argument that I don't altogether trust to be completely honest and unbiased, based on previous behaviour. Several of the authors on that paper would fall into this category. This doesn't mean that I don't believe anything they say, or that I will write off any of their papers without giving them due consideration. It simply means that I will look more closely at their arguments than I might otherwise. I have already listed some of the reasons why I felt the paper failed and I couldn't understand why they would go so far as to make the conclusions they did. On reading the author list, it became clear-ER why they might - i.e. they wanted the paper to fit the narrative. Not a "knee-jerk" reaction at all, but a considered response.

Secondly, where do I dismiss the break-up of the ice off Ellesmere Island? a. I never mentioned Ellesmere Island and b. I don't dismiss anything in the paper. I think the paper arrives at unwarranted conclusions but I do not dismiss it out of hand. What I did say though, was that there was undoubtedly something going on up there. We know that air temps on their own have very little to do with sea-ice melt. It's a combination of wind, ocean currents, air and water temps that cause the melting. Nothing stays the same in this world for very long and five thousand years really isn't very long. It may well be that the ice off Ellesmere Island is breaking up purely and simply because those things are currently aligned in such a way in that locality as to allow that to happen. Maybe it's entirely natural, maybe it's not. We just don't yet know enough to be able to point the finger with any real confidence.

Thirdly, I think you slightly misunderstand what a null hypothesis is. When you say that any null hypothesis must explain why adding more CO2 to the atmosphere wouldn't increase the amount of energy in the climate system, what you are actually asking for is an 'alternative' hypothesis, not a 'null'. As I understand it (and, as always, I could be wrong), a 'null' hypothesis doesn't have to explain anything. It's simply a metric that any hypothesis has to falsify before it can be said to contain any truth. In the case of climate, the 'null' is that everything we are seeing is within the bounds of natural variability. The hypothesis of AGW or ACC must first show that what we are seeing is beyond the bounds of natural variability (and thereby falsifying the null) before it can be accepted as a theory proper. With regard to the alternative hypothesis you ask for, my guess would be that any increase in energy in the form of heat in the system is likely to lead to increased formation of clouds (which I, personally, believe to have a net negative forcing effect) and, thereby, leading to an increase in the earth's albedo, leading in turn to a reduction in the amount of energy entering the system. Simples :)

Finally, I said I was just about a lukewarmer who was not quite an out and out denier. Whilst I fully accept the radiative properties of CO2, I also believe that's only part of the story and that other things happen (such as the clouds) that mitigate at least some of the effect. This means that I believe we are responsible for only a tiny amount of the warming seen so far and I wouldn't be in the least surprised if it turns out that releasing CO2 into the atmosphere actually has a cooling effect. Unlikely though it is, if such were found to be the case, then that would, in my view, be a whole lot worse and would see my voice added to those calling for a reduction in emissions.

Jun 27, 2011 at 6:58 AM | Unregistered CommenterLC

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