My essay about the language of the warming scare drew an audience larger than usual, and coincided with other examples of the use of language by some of the AGW orthodox (in my opinion) to deceive and distract. Let me start by making something as clear as I can. The last ten years have been warmer than the ten years before. But significant warming has ceased. Are these statements contradictory? No. They would be if I had written for the second statement: ‘The last ten years have seen a global cooling’.

The simplest summary for the last two decades is that by and large nothing much has happened. It hasn’t got warmer and it hasn’t got cooler. Some years it goes up a bit and other years it goes down a bit. Some are waiting for the next el Nino, which should jack up the temperatures a bit, and some are expecting things to get colder still. I wait and see. Inasmuch as the global temperature anomaly means anything, it’s all we’ve got to go on.

It fascinates me that the orthodox will not concede what the data so obviously show. You can see it in a familiar graph (familiar anyway, to those who follow the story of warming) of global temperature change from 2001 to 2014, using the average of the five principal global temperature datasets:


I used an earlier version of this graph last year, when the trend showed a very small amount of warming; this more recent one now shows a tiny cooling trend. What did the Summary for Policy Makers of AR5 do about these incontestable data? It ignored them. Instead, the SPM says something else that is also true: that every decade since the 1950s has been warmer than the preceding one. If the current trend continues to 2020, no later SPM will be able to make that claim. In any case, the SPM claim is beside the point: CO2 has gone up and up, and temperature has not, over quite a long period.

Here’s another example. A fortnight or so the Obama Administration released the National Climate Assessment, and that hardly made it into our news media, because it is about the USA. You need to know that President Obama is committed to AGW, but has trouble getting his desired legislation through because he doesn’t control Congress. The Assessment is a mammoth document, and I haven’t read it all by any means. But it is enough to read some of the language in the early pages. On page 1, for example, we learn that Climate change, once considered an issue for a distant future, has moved firmly into the present.  In fact, over the last ten years, and on the evidence, ‘climate change’ has become a less serious issue, and it is plain that we have some time to find out more about it.

What makes me grind my teeth is that this is supposed to be a scientific appraisal. The language is, however, that of the marketer, or the copywriter for television ads. Some of what is stated cannot be right, but it is boldly asserted, such as the claim that there are more tornadoes now. There aren’t, as Roger J. Pielke Jnr has pointed out. I hate this perversion of science. You can find out all about the NCA by going to its website, and go to Judith Curry or WUWT for the wide-ranging discussion of it. In fact, you can find a serious and pointed dissection of it by dissenting climate scientists on a recent WUWT post, here.

Example three: the great Antarctic disaster. Last week a paper was accepted for publication in Geophysical Research Letters warning of the ‘collapse’ of the West Antarctic ice sheet, which was ‘unstoppable’. The italicised words are there because they were used in the media discussion of the paper by the authors, and they have technical meanings. It is a ‘collapse’ in the sense of the collapse of the Roman Empire, and thought to be unstoppable because the sub-surface topography of the ice sheet points towards the sea. If it all happened, the authors said, it would take several centuries if not more, and that could raise sea levels by 4 feet. You can read all about it most usefully in a New York Times piece by Andrew Revkin, in his blog.

What happened in the media? ‘Unstoppable collapse’ became the topic for the day, and a four-feet increase in sea levels, which might not ever happen, and would not happen in a dozen lifetimes even if it did, morphed into a fourmetre increase. Indeed, I heard Margaret Throsby on Classic FM and her scientist guest going into the ghastlies about the threatened prospect, which would end Bangladesh and other seaside nations. Plainly neither had read anything other than media comment. The Governor of California thought that Los Angeles airport would have to be moved (it is 38 metres, or about 125 feet, above sea-level). Why would you say something that is so wrong — and so easily checked? (His office corrected the statement a day or so later.)

Example four: at the time of writing comes another scary story about the link between wildfires in the USA: more fires and worse fires in California and Arizona over the last year or so. What caused them: ‘this is what happens when the earth warms’, said one of the authors. And the actual evidence is clear:

clip_image005_thumbWildfires have been declining in number since 2006, and over the last 27 years the numbers rise and fall and then rise and fall again, as they do in Australia. Why? Rainfall and fuel load are the key factors. California and Arizona have been dry over the last few years because when we get rain from la Nina conditions they get drought. So in the US South West they’re looking forward to an el Nino  later this year. ‘Bring it on!’ they cry.

How could a scientist state confidently that something is the case when it isn’t? The earth isn’t warming, either. And if it were to warm significantly again, there should be more rain, because more heat > more evaporation > more rain — somewhere, at least. Perhaps, as some sceptics say, the frenzy gets louder and more acerbic because the evidence is going the other way.

This stuff makes someone like me bad-tempered, in part because it is dishonest, in part because it leads to bad policy, and in part because it weakens science. An end to it! I say.


Join the discussion 60 Comments

  • PeterE says:

    Oh dear, oh dear, what is to be done? The nonsense goes on but I suspect that fewer people are being taken in. Where possible, challenge the falsehoods, as this column does. Challenge especially the use of taxpayers’ moneys. May the Force prevail!

  • DaveW says:

    I think they are just doubling down. When your lie is challenged what can you do? Tell more and bigger lies (and pray for a super El Nino).

    I used to be angry about the twisted ‘science’, but that was when I confused ‘climate science’ with science. Probably any area that needs to tack ‘science’ on to its name is not a science. Real scientists study a system with the intent of understanding it and generally get by with an -ology (or are physicists or engineers or mathematicians). The real scientists caught up in the AGM funding tsunami would probably be perfectly happy to be called climatologists, meteorologists, physicists, dendrochronologists, palaeontologists, geologists etc.

    Climate Science is a branch of social science and its Svengali, politics. Climate scientist don’t want to understand climate, they want to impose their political views on the discussion of climate. If it weren’t for their hold on the media and politicians, Climate Science would be no more annoying than any other social science. It certainly is no more useful for policy.

  • Dasher says:

    Had a chat with my young (smart 26) niece about climate change. She had assembled quite a dialogue of “facts” on the subject….but they were clearly from the warmist perspective (e.g. the 97% agreement figure was seen as rock solid) I offered some alternative views along the lines of the above (including introducing her to the fact that the 97% is very dodgy) and suggested she and her friends not rely solely on this warmist perspective…noted that many things have happened which never get a mention, or if they do,it can be very distorted in some media in this country. Being a sharp kid she asked did I think they lacked curiosity…I replied I could not have put it better….we shall see what transpires.

      • Don Aitkin says:

        Dasher’s niece might say that these data are about the Western states of the USA, where there have been several years of drought brought about by la Nina conditions, just as we have now had several years of more than average rain. And DA had pointed that out in his post.

    • David says:

      Dasher please forward the link below to your smart niece. Hopefully she will will make a better fist of understanding it than her uncle.

    • glentonjelbert says:

      Nice link David. Shows how the cherry picking continues. Number of fires stays the same, size of the fires is growing – so what data do we show? Worst drought in California in recorded history, unprecedented fire levels at this time of year, state of emergency, fire fighter numbers at their peak months earlier than normal. Flooding in Serbia. Response: Everything’s fine, guys.

      • DaveW says:

        I’ve always wondered about cherry picking defences of CAGW. Is this a formal debating strategy? By using cherry-picked headlines of disasters is this supposed to somehow immunized you from criticism of cherry picking or is it designed simply to pre-empt the opponent? In any case, I don’t think it works very well – makes you look like a hypocrite or someone with clouded thought processes.

        What I see is unprecedented cherry picking levels in the Chicken Little League with some goal post moving (not more fires, well then they must be bigger; not the worst drought known, well the worst in ‘recorded history’). I checked the ABC news site this morning, but alas, no new disasters to support your hypothesis. Akubra does have a shortage of rabbits, though, so everything isn’t fine after all.

        • glentonjelbert says:

          So to define cherry-picking, it means using some data instead of a more complete data set. So use of one graph, instead of both in this case. I don’t disagree that there are plenty of sensationalist headlines. It irritates me too. On the other hand, the ‘explaining away’ is getting pretty weak too. One would expect that record-breaking events get less and less frequent with time. Yet we’re seeing the opposite. One of the issues with climate change has always been an increase in severity. So dry gets drier, wet gets wetter, hot gets hotter etc. You can quibble the details if it makes you feel better, but it’s pretty clear that we’re seeing that already.

          It’s interesting to imagine an alien viewing events from space. Okay, they organised their society to get thousands of scientists from across the world to study the impact of carbon emissions. The scientists put thousands of experiments together and worked tirelessly to understand what’s happening. They can explain it and understand it and even make predictions within a range. They put this all together and suggest that people make a bit of a change. And society at large collectively shrug their shoulders and say that the results can’t be right, because they don’t want to change. Anyway I read a blog post for 5 minutes, and already understand more than these idiots who’ve been studying it all their lives. I mean, if we’re not listening to these guys, who are we listening to. The Koch brothers I suppose. The heritage foundation also says that second hand smoke is not bad for you. It’s a very comparable argument, actually.

          • Don Aitkin says:


            I take ‘cherry-picking’ in this context to refer to one’s choosing starting and finishing dates to support one’s argument. I don’t think I did that, but if you think so you might point out to me where I did it, and what alternative I might have used instead, and why I ought to have used it.

            You make some other comments that I found interesting. Someone else has taken you up on a few of them, but I made add a new comment later today, if I have time.

          • glentonjelbert says:

            Cherry-picking is more generally selecting data or even data sets to show a particular perspective.

          • DaveW says:

            “The scientists put thousands of experiments together and worked tirelessly to understand what’s happening.”
            If only that were true. Instead we get lots of model prevarications, constantly changing predictions, increasingly obscure buzzwords (global warming => climate change => climate disruption), and anyone who dares disagree with the consensus stomped.

            Exactly what ‘record breaking events’ that are not dependent on increasing population and wealth are becoming more common? And no, I would not expect record-breaking events to decrease with time – you have to have a record before it can be broken and I would expect a certain number of them to be broken every year. Most of the land temperature records are clearly attributable to UHI effects and other land use changes and mostly trivial differences over short record-keeping spans. Recent fire history in North America and Australia has a lot to do with failed fire control strategies and peoples’ desire to live in the bush and nothing to do with a changing climate.

            Where are the US landfall hurricanes? The Australian ghost cities destroyed by drought? The snowless winters? The iceless Arctic? The reason no one but the gullible believe in CAGW anymore is that it has been based on a series of lies and exaggerations. Crying wolf applies directly. Yes, maybe one day the wolf will be at the door, but no one really seems to know what is happening with the climate. That hasn’t stopped the CAGW lobby from spouting off what has so far invariably proved to be nonsense. You are right that aliens observing us from space should be aghast – just not for the reasons you think.

          • glentonjelbert says:

            Hi DaveW. Media exaggerations are indeed frustrating, but shouldn’t be confused for the underlying science. The way science works is that data is gathered, and models are created to describe that data mathematically. That’s what scientists are doing. I shared a link of the thousands of papers above where you can see this work in action. On the models, please see Gavin Schmidt’s TED talk:

            Where are the models of the climate change deniers? Surely if you have a valid perspective, it can be explained mathematically? And I don’t mean Roy Spencer’s “model”, where he could fit basically anything to it.

            If you’re looking for a very simple model there’s one here, which agrees with the more detailed GCMs:

          • DaveW says:

            Hi Glenton – Well, if you agree that media exaggerations are frustrating, then maybe you shouldn’t cherry pick them to make a point (which is the point I was making).

            “The way science works is that data is gathered, and models are created to describe that data mathematically.”

            I’m fairly familiar with how science works and your definition is not standard. A mathematical model can be written to fit any data set and there is nothing scientific about doing so unless one intends to test a hypothesis. Perhaps you find that idea too Popperian, but it is the consensus in most science (although perhaps not in Climate Science). The primary problem in Climate Science, as in many social sciences, seems to be that a preconceived conclusion based on theory is assumed true, a test or model is derived to prove the truth of the theory, and when the data won’t cooperate it is manipulated or ignored.

            If the science is really settled, then I suggest we stop funding climate models and climate research and concentrate on preparing for the future.

          • glentonjelbert says:

            I would have to disagree on multiple points. There is a difference between cherry picking to make a point that disagrees with the scientific consensus which is based on all the data, and showing a selection of illustrative data that agrees with the consensus which is based on all the data. The scientific consensus is clearly the important underlying view (ie the best understanding that has been gathered from all the data). Illustrating that for people is an honest attempt to educate them on something quite complex. Picking out data sets and then proclaiming that the whole understanding is undermined is disingenuous.

            I think I won’t get into the philosophy of science discussion with you. I could refer you to quotes from any scientist from Plato to Feynmann, but it’s a little tangential to the central issue. You view climate science as a social science, which is frankly risible.

            I would agree with your last paragraph, and I think most scientists would agree that we should start concentrating on preparing for the future. In fact, if scientists were really chasing the funding, they would probably not be as unequivocal as they are. Scientists are saying that we need action and now!

          • DaveW says:

            Hi Glenton,
            You clearly have a very high opinion of both your scientists and your own understanding of matters. That you find arguing from authority legitimate and can rationalize cherry picking in the cause of the ‘consensus’ puts you very much in the centre of the Climate Science herd and supports my contention that it is a ‘social science’ (no insult intended to sociologists who are trying to actually understand human societies as opposed to pushing a political theory).
            Unfortunately for your understandings, most people trying to do science would find your logic anathema. Application of the scientific method is really the only way science differs from other human endeavours. Appeals to authority and ignoring inconvenient data have no place in science, although they can help advance one’s career.

            Good luck with your world view.

          • glentonjelbert says:

            Hi DaveW. You can choose to believe whatever the Koch brothers decide you should believe, through the various institutes whose opinions are for sale. Here’s another issue from the Heartland Institute:

            If you take this article and do a couple of artful replacements, you have the same basic argument as is used for climate change. I don’t know why an Institute whose opinion is so clearly for sale is so compelling to you.

            Do you believe that smoking is not bad for you? Do you believe that vaccinations are worse than the disease they’re protecting you from? I don’t think I’m the one who can be accused of ignoring science here. Over the years of this so-called debate I’ve seen arguments as follows.

            We don’t need to change because…
            1. It’s not happening,
            2. It’s happening, but we’re not doing it,
            3. We’re doing it, but it’s not going to be serious,
            4. It’s going to be serious, but it’s cheaper for us to leave it to our grandchildren to sort out.

            You can’t plausibly believe any two of these arguments without some serious cognitive dissonance, but people argue for multiple. The reason is that they *know* that they don’t have to change, so it must be that one of those (mutually incompatible) ideas is true. Talk about predetermined conclusions! This is why your views are considered to be pseudoscience.

            That’s also why the argument has shifted to the (also incompatible):
            1. There is no consensus
            2. There’s a consensus, but it’s because all scientists are in on a giant conspiracy (and that’s the only reason they won’t publish my ideas on the matter)
            3. There’s a consensus, because the scientific method has mysteriously stopped working and all these foolish scientists can’t understand an argument even I get after reading a blog for 10 minutes. 1000s of physicists who came top of their class and then did a PhD and then spent years studying the issue just don’t get it.

          • DaveW says:

            Hi Glenton,
            Thank you for the various inaccurate statements about what I believe and who I regard as authorities. It shows a lot about your thought processes (or lack there of). I know you won’t be able to understand this, but I am fully capable of assessing data and coming to conclusions on my own, without any appeal to authority. I’ve been doing it for decades and I am considered an authority in my field. When people ask me for an answer, though, I make sure they understand it is an opinion based on certain experiments or observations, not a statement from an oracle.

            My conclusion is that no one seems to know what will happen with the climate over the next few decades. No one knows if it will cool or warm or by how much. Amazingly, even scientists and global circulation modellers are unable to see the future. You have a crystal ball, though, so you have an advantage over someone who is just a scientist used to evaluating claims based on data and coming to conclusions on their own.

          • glentonjelbert says:

            Ah, you’re considered an authority in your own field, used to the little people hanging on your every pronouncement. It must be frustrating to have your proclamations questioned. No wonder your comments have become increasingly personal. You should write a paper in which you summarize your understanding of all the data and get it peer-reviewed. I don’t know if there’s anyone else out there who is “fully capable of assessing data and coming to conclusions” on their own who would be capable of reviewing it, but maybe they could understand it if you explained it carefully.

          • DaveW says:

            Hi Glenton,
            I do appreciate your energy level, but your logic isn’t improving. I was much more personal in my very first comment than anything I have said later, although you have become more insulting and patronizing. Par for the course on climate blogs, but it is a bit rich to accuse me of becoming ‘increasingly personal’ right after delivering an insult. Lighten up – neither one of us is going to save the world or send it into damnation.

            I don’t have anything to prove: you are the one making the claim to know what is happening. You are the one that needs to prove their case and with rigour, not with poorly formulated lists or Koch brother brickbats. As I said, I do not see any clear answers as to what the future may hold. I’d say we don’t know what we should be doing, if anything, because we do not understand the climate yet. You think you do, so maybe you should write the paper and get it peer reviewed. Call it something like “Why DaveW has his head up his arse”.

            I have been trying to understand where you are coming from. Why do you have such an unquestioning belief in your scientists? Why do you claim to be against cherry picking but perfectly happy to do so to support your cause? Why do you think you know so much about the future? Why did you suddenly show up here and take on everyone? I give up though. You are a mystery.

            Cheers & Goodbye

          • glentonjelbert says:

            Well thanks for the discussion. I see now that I’ve been illogical and should be writing papers about you rather than rely on the extant body of knowledge.

      • Peter Kemmis says:

        Hi Glenton

        Thought you might enjoy this article at .

        I note that the IPCC does not argue that the weather we are getting is extreme, or indicative of CAGW. There are many records we have of prior droughts, heat waves, cold spells, and wet spells, going back to the early 1800s. Like the writer of that article, I remember many of those we’ve experienced since the 1950s.

        Drought in California? Ever read Steinbeck – he’ll tell you about dust bowls.

        Fires? I’ve fought a few big ones, as a trained rural fire fighter. When there’s minimal moisture in the soil, lots of fuel, very low humidity, that’s when you know you’ve got your work cut out. Long dry spells following good rains and growth is a bonanza for grass fires – they’ll create their own winds. Minimal hazard reduction (i.e. burning off with “cool fires”) leads to build up of fuel in timbered areas – so the very aim of not harming the flora and fauna by reducing the fuel with cool fires, is more than knocked on the head with the big fire that is bound to follow, with far more serious consequences. So there are quite a few factors in the size of fires, and frequency. Spotting fires early and acting promptly, can give control early. More people around, more likelihood of accidents (eg angle grinders and sparks, or just cigarettes), and sadly, more arsonists. So just be careful when you start talking about fires, as there are lots of considerations there.

        Hurricanes in the USA? Their frequency is actually dropping. Did you know that?

        Floods? Take settlement and land use changes into account, at the very least. And check out the rainfall records at the same time. We can’t blame the weather, let alone the climate, if we build in flood-prone areas.

        It’s not that I don’t care – but you mention elsewhere adaptation. Well, there’s a lot we should already do differently, were the climate to stand still, which we all know it won’t.

        Any more cherries for me to pick, or will that do for the moment?

        • glentonjelbert says:

          So the 70s cooling period has been mentioned a couple of times. It’s again a case of the influence of sensationalist media rather than an understanding of the science. Some points on that:
          1. Our data sets and computational power have increased dramatically since then.
          2. We understand the cooling trend of the 70s to be related to aerosols and limited to the northern hemisphere.
          3. Even at the time, 10% of the 68 papers on the subject said cooling. 28% had no stance. And 62% predicted warming. (scientific studies on “global cooling” from 1965 to 1979)

          I discussed the models a little bit below. I should mention that decreasing records is a matter of mathematics, not opinion. If you have 100 numbers in random order, the first one will be the biggest so far. The second one has a 50% chance of being the biggest so far. The third has 33% chance of being the biggest so far. Etc etc. By the time you’re onto the 100th one, it has a 1% chance of being the biggest so far.

          I think the Serbians might take issue with your views!

    • Don Aitkin says:

      Because I thought the argument was well known and the data likewise. There are hundreds of graphs that show the flattening over time. Here’s another. As you will have read here before, I’m not happy with the reliability or validity of the data from before WWII, but the flattening of the temperature in the recent period is clear enough here.

  • GenghisCunn says:

    Don, I read that the authorities in California thought that a number of fires had been lit by “eco-activists” in order to help sell their scary anti-warming message. I’ll follow that story with interest.

    • Don Aitkin says:

      I’d wait until someone is caught and confesses. Almost certainly there are people who light fires deliberately, and some have been caught in Australia. So far I don’t think any of them has confessed to being an ‘eco-activist’.

  • glentonjelbert says:

    It is interesting to see the cherry-picked data in conjunction with the frenzied rants about bad science, complaining about the increased rants and weak science from the ‘alarmists’! (Incidentally, plenty of scientists pick holes in any media misrepresentation on either side. See for example potholer54’s fabulous youtube videos on both Lord Monckton and Al Gore).

    The data set for the 97% is available on-line. Readers of raised the money to ensure that it wasn’t behind a paywall (the so-called author pays model for anyone following that debate on academic publishing). My advice is to go to the source and check it out for yourself.

    Presenting the surface temperature as a proxy for global temperature is also disingenuous. Is this simply confirmation bias (ie a tendency to write about graphs that appear to support your view)? I mean there’s no doubt that more energy is coming in than going out, right? So that energy is going somewhere…

    • Don Aitkin says:

      On the 97%, see the piece I wrote about it last year, at

      On proxies, what is your preference? And why is it better?

      ‘I mean there’s no doubt that more energy is coming in than going out, right?’ Well, maybe. No one seems to be able to show where it is. Perhaps it has escaped…

      • glentonjelbert says:

        Hi Don. Your article is a great polemic. But I’d recommend looking at the actual paper and the actual data instead: If you look at the methodology, and what’s actually stated, you’ll see that Curry is distracting from the main point with conspiracy theories, rather than answering it.

        “No one seems to be able to show where it is. Perhaps it has escaped…”?! I’m struggling to even understand what this statement means. Are you saying that there is no scientific literature on this? Regardless, global warming means that the surface, the atmosphere and the oceans are all warming. The oceans are by far the biggest piece of this. But there is data available for all of them. There is also data on how much energy is coming in from the sun, and how much is escaping in infrared.

        So I’d say that looking at the data for the whole system is better than looking at a proxy for the whole system.

        In any event, having the hottest decade on record when solar activity was at a low is not a cause for celebration.

        • Peter Kemmis says:

          Hi again glentonjelbert

          I agree very much with your view that we should look at the data for the whole system. I’ve found it very informative to go well beyond the Industrial Age, as well as looking at the hard data of measurements over the last half-century. Starting points for me were land and sea surface temperatures (and now those from ARGO floats), ocean level rises, and sea ice extents. For me, there’s no argument that we’ve seen a gently warming world (thank goodness) since the last Little Ice Age of some 300 years ago. But there’s been no acceleration in ocean level rises, and now we have a well recognised plateau in air and sea surface temperatures. The ARGO floats are not reporting any increase in the rate of ocean warming. There is no tropospheric hot spot as predicted. Arctic sea ice has certainly been shrinking, while Antarctic sea ice is growing.

          “The hottest decade on record” .. . . well, our records based on thermometers are pretty short, but we do have records of some pretty hot periods in the 1800s here in Australia. So I do wonder about that phrase. Especially when I think of the Roman and Medieval Warming Periods as well.

          So my conclusion at present is that the human contribution to warming has been minor.

          • glentonjelbert says:

            Hi Peter. Thanks for the welcome. Your conclusion is at odds with the scientific understanding of the situation. But to respond to your earlier question about temperature flow, see here:'s_energy_budget. Judith Curry has an article about this arguing that the uncertainty is too large, but when you dig into it, there is uncertainty (as there always is when you’re taking a difference between two large numbers), but even so, there’s a clear accumulation of heat (it’s just a question of how much). The ocean heat content is increasing. The volume of ice in the Antarctic is decreasing. More recent data sets of the flat graph above actually do show an increase. It’s related to the amount of sampling at the poles, where much of the heating occurs.

            But a lot of this is a distraction from the central issue.
            1. CO2 in the atmosphere has increased by the amount that humans have put in it since the start of the industrial revolution. So we did it.
            2. This CO2 is causing climate change. It’s an open question as to how much exactly, but it’s between a lot and a huge amount. This is already in the bank, so to speak.
            3. Mitigate vs adapt? Well, we’re going to need both. Most likely, because of this debate, we’re going to need to try out some geo-engineering too.

            The trouble is that people form their opinions to align with groups they identify with. So you have arguments about certain data sets that are increasing but not accelerating. What’s causing the increase? What are the key mechanisms? What is the significance of CO2 to this story? Most importantly, what’s going to happen next? Is there something deeper behind your beliefs, or have you just got a minimal set of facts that allows you to continue with the position that no change is needed? I don’t mean that question sarcastically. It seems that many people “read a lot” on the issue, but are applying a significant filter whereby they absorb ideas that support their beliefs, and discard other ideas, explaining them away even as they read them.

          • Peter Kemmis says:

            Hi glentonjelbert

            Thank you for your thoughtful raising of many issues; I’ll try to respond briefly on each.
            1. Scientific understanding – I’m well aware of the current orthodox view, which on the basis of what I have learned I do not accept. We must agree to disagree on that. The temperature flow diagram I have seen earlier; it’s a good graphic reflecting the orthodox assumptions, no doubt incorporated in all climate models. I note that the models have largely failed to show the current global temperatures, and failed to predict the current “pause”.
            2. “Clear accumulation of heat”? You suggest the ocean heat content. The ARGO floats (first ones deployed in 2004, I think and the full 3000 by 2007) are showing no acceleration in ocean warming, just the steady rise we have been seeing as we warm up from the last Little Ice Age.
            3. Decrease in Antarctic ice volume? Would you mind letting me have the source/s for this assessment? Given an increase in sea ice, I find it hard to imagine that land-based ice is not being regularly replenished from a similarly increased dumping of snow, turning quickly to ice in the weather the Antarctic is experiencing. But I do not know if that replenishment is less or greater than the normal loss through movement of glaciers such as the Thwaites.
            4. I accept that much of the carbon dioxide increase is due to human activity since the Industrial Revolution. Some of course arises as the oceans warm, which is the reason that ice core and other proxy data show an 800 year lag between temperature changes and carbon dioxide levels. It is generally agreed that humans currently contribute some 3% of these global emissions, primarily through fossil fuel use, land clearing and agriculture. I do not accept that these emissions are causing climate change to any significant extent – as we are both aware, this issue is the nub of the debate. So again, we shall agree to disagree.
            5. Mitigate and/or adapt? Our history has shown considerable change in climate, from the extremes of deep ice ages to the current Holocene. I argue that we should indeed adapt; we have plenty of natural disasters with huge impacts on societies, and we should change much.
            6. The danger of “group-think”: I agree very much with you on this, and suggest that your last paragraph could be readily applied to each side of the climate debate.

            Finally, I’ll write a separate comment shortly about “consensus”.

          • glentonjelbert says:

            Hi Peter Kemmis. So you say that you disagree with the consensus (or orthodox) view, and that you don’t think there is a consensus. You also say that much of the carbon dioxide increase is due to human activity, but that these emissions are not causing climate change. You say that the temperature is just gradually rising, since the last ice age, except for the warm period and the cooling in the 70s and the last decade when it’s just leveled off. Is this all correct?

            You’re probably talking about the Oregon Institute for Science and Medicine, when you refer to the petition of 30,000 people. So you find that persuasive, but not Cook et al? Why is that?

            Do you accept the greenhouse gas effect? Does CO2 absorb infrared radiation, and then re-emit it in a random direction, effectively causing some of the radiation to be reflected back towards earth? How do you account for your idea that the earth is gradually warming? What is the mechanism? And how do you square the idea that humans are responsible for most of the increase in CO2 levels with the idea that temperature increase apparently precedes the increase in CO2?

          • Peter Kemmis says:

            Hi glen. . . (hope the abbreviation is OK with you)

            Oh, you are making me work, aren’t you? (I’m taking a few days holiday by the beach!) First, some corrections to your para 1 above.
            a) I do think there is a “consensus” view, which more accurately should be called a majority view. I suspect if one could obtain responses to a carefully devised and comprehensive questionnaire from a wide range of scientists around the world, the levels of agreement to various questions and support for different measures for a range of scenarios, would vary widely. A major problem with these surveys we have at present, is that they are simplistic, and do not differentiate meaningfully. They seek a simple binary result – yes or no. That’s really trivial. The letter I mentioned above does cite a range of reasons and qualifications, and is therefore useful.
            b) I stated the temperature has been rising since the last Little Ice Age (not the last ice age), which started to wrap up its snowboots around 1680-1720. Overall, the temperature has been gently declining since the end of the last deep ice age, but as one can see from the proxy-based reconstructions, it does vary between a quite narrow range. Over the last 2000 years, we have had both the Roman Warming Period and the Medieval Warming Period. We are currently still within that slowly declining range. The current “levelling off” now stretches over about 17 years. I hope this addresses any misunderstandings relating to your first paragraph.

            Now to your further points:
            c) Cook’s paper has been examined by people far more able than I, such as Steve McIntyre. I’m not satisfied with the method of analysis, or the independence of the assessors. Further, given the emails relating to the genesis of the study, it is clear that a defined outcome was sought from the beginning.
            d) The “greenhouse effect” – this is an unfortunate term, because it is so inaccurate. A greenhouse reduces much heat loss through limiting convection. Our atmosphere behaves quite differently. Carbon dioxide does absorb infrared radiation as you describe, but only within specified bandwidths. John Morland has described this in some detail on this site, perhaps some two weeks ago. You might care to look that up. We are still finding out a lot more about how our atmosphere keeps us nicely warm, including the behaviour of clouds In both reflecting heat outwards as well as supporting heat retention, their formation, the role of particulates, the potential significance of cosmic particles in seeding the formation of droplets from water vapour – the list of unknowns is extensive. To put the differentiator down just to carbon dioxide I do find rather facile.
            e) “the earth is gradually warming” – actually, as I said above, it is gradually cooling overall, but we have been in a short warming phase over the last 300 years or so, with a few ups and downs (such as the cooling from the 1940s to the 1970s, which I imagine gave rise to the conviction by some scientists that we were heading towards an ice age, which I mentioned earlier).
            f) In addressing (e) above, I’ve been asking the broader questions: what causes an ice age? and what leads to inter-glacials such as our present Holocene? So back to your question “how do you account . . . for the earth gradually warming” (may I add, “and cooling”)? This is an excellent question about the mechanism, which is quite independent of our recent industrialisation. May I suggest you get hold of Vahrenholt and Luning’s book “The Neglected Sun”? Among other things, it provided me with some fascinating insights on major climatic cycles. It also demonstrated to me how little we know yet on this whole subject of changing climate (and I don’t mean AGW, I mean climate change). Yes, what is the mechanism?
            g) Your last question is another good one. The increase in carbon dioxide levels to which you refer, is of course the rise since 1800 or so. There can always be more than one cause for a single effect. We can observe the natural releases of carbon dioxide in the oscillations shown for the CO2 faint line in the chart Don provided above. As you know, these arise as the growing season in the northern hemisphere fades so that CO2 conversion to oxygen and plant fibre is reversed, with the decaying leaves and other vegetable matter releasing CO2 – the cycle of life. I’m relying on the findings from proxies such as ice cores and tree rings and sediments, that CO2 rises follow warming by about 800 years. So we’re about 800 years after the Medieval Warming Period, aren’t we? I don’t know how much humans are responsible for the rises we now observe, and how much is natural. Do you know? And have I answered your last question fully? Perhaps you see a contradiction that I do not yet understand.

            Thank you for your questions, challenging as they are. It is refreshing to be able to engage in serious dialogue such as this. Some time back I sought to do so on a well-known “warmist” site, and was in a very short time moderated out. My tone and measure was just as courteous as it is in our discussion; it was simply that my views were not acceptable. Moderation of that kind, namely censorship, does not happen on this site.

          • glentonjelbert says:

            Hi Peter Kemmis

            You’re very welcome to search through the list of papers and decide what they said for themselves. Here’s a link to the Cook et al paper: I would highly recommend that you assess it directly, rather than view it through a lens. You can see that they simply took all the search results to get 12000 papers, and assessed the abstracts. You can see the list of papers there also, and how they assessed each one. It’s all completely open. It’s very far from a binary yes/no. It’s an assessment of an abstract, which is a crafted and nuanced summary of a peer-reviewed paper.

            The 30,000 signatories of the OISM paper had a far lower bar, and very little information was released. People who signed self-assessed as to whether they had a degree. A BSc was considered sufficient. At that level, there are 10,000,000 scientists in the country. So they got 0.3% of those. They never released the information about how many respondents they actually got, so hard to know. To me, it requires extraordinary mental gymnastics to dismiss the former and rely on the latter. But you’re right that it was a simple yes/no type of survey in this case.

            You seem to have a lot of views on how things were, but where did these ideas come from? Are they your views? If they are not from a peer-reviewed source, then we have to understand what other cause for credibility they have. The scientists who gathered and analysed all the data on which you rely disagree, so who is it that you are agreeing with exactly? Are there models? Peer-reviewed papers? How important are the different mechanisms you mention relative to each other? How would you assess that?

            The way a scientist would assess it, is to build a model that incorporates all the effects you mention (sun, clouds, CO2, aerosols, volcanos etc). Oh, and many of them did. And they all say that we’re causing climate change and it’s going to get worse.

            I’m sorry you were not welcomed with open arms on a “warmist” website, but I guess they have little patience for fiat assertions that contradict the body of peer-reviewed literature.

          • Peter Kemmis says:

            Hi Glenton

          • glentonjelbert says:

            Hi Peter Kemmis. You keep talking about the pause. There isn’t one. You suggest that this was completely unimaginable. It wasn’t. It was within the error bars of the models. You say you set store by peer review, but distrust it because of the funding (a risible argument as anyone who’s actually been through the peer review process and also tried to make ends meet on academic salaries can attest to). You say you personally look at primary observational data. That means you gather the data yourself and analyse it yourself? There is no scientist on earth able to make such a claim. There are multiple data sets from myriad experiments, each an expertise in its own right. If you’re relying on your own data, you’re essentially relying on anecdotal evidence. If you’re relying on the data of others and analyzing it yourself, then you should get your analysis peer reviewed. If you’re unable to convince your scientific peers, then it would be grossly irresponsible to try to convince the public at large.

          • Peter Kemmis says:

            Hi Glenton
            1a. The “pause” – I am not sure whether you’re saying there is not, or there is one. You say above “There isn’t one. You suggest that this was completely unimaginable. It wasn’t. It was within the error bars of the models.” So is there one, or isn’t there one?
            1b. As far as the error bars are concerned, may I refer you to Figure 1.4 of AR5? That shaded grey “error bar range” was added for AR5 – it was not there at the time each report was issued. In my judgment, almost all of the IPCC models have significantly over-estimated the observed global temperatures. Some few weeks back Don posted a useful graphic showing all the model predictions, overlaid with the actual temperatures.
            1c. On Xmas Eve 2012, the UK Met Office (one of the four principal authorities on which the IPCC relies for data), made a public statement that there had been no statistically significant warming or cooling over the prior 15 years. We are now into our 17th year. In the view of many, that constitutes a pause in the warming trend of 1970-1998. Over millennia, each will hardly be a blip. But you are free to say it does not constitute a pause. Perhaps we could both agree between ourselves that we’ll call each of the two periods a “blip”.
            2. My statement was not that I look at “primary observational data”; it was “My starting point is the observational data, and it remains primary”. My meaning is that the observational data is of uppermost significance, and my sources are the formal bodies whose information is used by everyone working in and around climate science. It is publicly available information.

            I look forward to your comments on my brief criticism of the Gavin Schmidt presentation, as well as to the points I made in my earlier response under b), d), f), and g).

          • glentonjelbert says:

            So there’s clearly a pause in the surface temperature. That’s only about 2.3% of the earth’s heat content. You can see the graph here, which shows that overall the earth is continuing to warm, most notably in the oceans:

            The graph you refer to ( would always have error bars associated with the actual data, regardless of whether they were shown or not. Regardless of the error bar, the actual data is within the range predicted by some of the models. And surface temperature is not necessarily the best thing to use.

            The UK Met Office was also talking about surface temperature.

            Using your judgement on selections of data (gathered by scientists) to come to a conclusion that contradicts their far more informed views requires a fairly large amount of hubris.

            Specifically, hanging your hat on surface temperature is probably not the most robust strategy.

          • Peter Kemmis says:

            Hi Glenton

            Thank you for your opening statement that “there’s clearly a pause in the surface temperature”. I was concerned that our discussion might have reached an impasse, which would have been a pity.

            I consider there’s a good reason to use the air temperatures, which are now augmented by satellite measurements: they have been used as a most significant reference point in every IPCC report so far. Why should they be now seen as less significant measures of what is happening with the climate, especially concerning heat content and the heat balance to which you’ve earlier referred?

            Thanks for including the temperature anomaly chart above, which I think is from AR5. Regardless of error bars, the chart clearly shows that the models have consistently and significantly overestimated climate sensitivity. Error bars are derived from a range of uncertainties at specific points in the models. The uncertainty values themselves are subjective.

            I looked at the skepticalscience site you referenced, and noted the claim about increasing ocean temperature. Yes, it is still increasing, as I would expect after the warming of 1970-1998 or so. I understand there’s generally a 20 year lag of ocean temperature rises following air temperature rises. But there is no acceleration in that rise, just as there is no acceleration in the ocean level rise. The claim that the “missing heat” is going into the oceans is not supported by ARGO float observations. I will not accept current models as proof of actual change; if one assumes the AGW argument, one can build a model which places the missing heat in the oceans, and “hey presto”, the model tells us the ocean temperatures are rising, so that’s where the missing heat has gone! Honestly, that is what I suspect is occurring in the modelling world.

            I found the James Wight’s article in skepticalscience site interesting for another reason; at the end of his article, he asks “Why has the ‘pause’ myth gained so much publicity?” He then by implication provides the answer in his quote from David Fogarty (ex-Reuters). David’s account indicates to me that there are some in the media world who are indeed taking note of that pause, and asking the same questions many are asking.

            incidentally, my earlier reference to an old fairy story was not facetious. You see, in my working life I’ve worked with many areas outside my own expertise. Like most of us, I’ve had to make judgments about the quality and consistency of information provided. A lot of trust is also involved. You have previously and correctly implied that it is impossible for a single person to have a thorough understanding across all the relevant fields in climate science. You also have to trust others. What are your criteria for assessing the information you receive, upon which you will base your conclusions?

            I look for consistency across the range of information I have available to me. I look for consistency in argument. I pay attention to tone. And I certainly consider human nature, because so much of what is presented to me comes through that filter of human nature.

            So I find some of the old fairy stories and proverbs and Aesop’s fables are timeless. And I still make significant mistakes! Anyway, I’m thinking of Aesop’s “The Boy and the Wolf”, where the Boy is science (being in this case represented by climate science). The greater cost will not be the loss of community faith in climate science, but in science as a whole. It may take a generation to recover that faith, a generation for science to recover its reputation.

          • glentonjelbert says:

            You ask my criteria? If something has been peer-reviewed, I’ll take it seriously. If it’s been repeated, I’ll take it more seriously. If multiple different sets of data point to the same thing I’d be very inclined to accept it. Ie, I would say that this is a view that aligns with the current scientific understanding of the situation, and we should act accordingly.

            For someone who’s looking for consistency you’re putting an awful lot of emphasis on the Argo floats.

            I think science is not taken very seriously already by many in the general public, but I ascribe it to poor education rather than poor science. The scientific view on this issue is pretty clear and readily available. Opposing that view requires extraordinary mental gymnastics. To me this is not about stories and fables, but about sound risk management and decisions in the face of uncertainty.

            However, since you like stories let me make one up for you. Two people were going to take a flight. On the way to the plane, the aeroplane’s mechanics, who’d been studying the plane for some time, came up to them and said: “we think the wings might fall off this plane.”

            They all started to discuss it. Some mechanics had noticed the way the planes wings were vibrating when it taxied. Some had noticed a change in the wings dimensions. Others had noticed internal structural damage. Others had reports of certain noises from the pilots. Other had CTC scans. All believed it pointed to a risk of the wings falling off.

            “How likely is this to happen?” said one of the passengers.

            The mechanics argued based only on what they’d seen and estimated. Some said 10%. Some said 20%. Some said 5%.

            One passenger turned around and said his business was not so urgent as to take such a risk. He’d fly another time. The other said “these mechanics clearly don’t have a clue what they are talking about. They can’t agree with each other at all.” and he walked on and climbed on the plane.

          • Don Aitkin says:


            You seem so confident about all this, and after nearly ten years of serious study of global warming I grow less and less confident that we have any real understanding of what has been happening.

            Since I’ve had many years of experience in the world of peer review, I don’t take it as seriously as you do. I’m mostly a fact-grubber, a lover of data, and a tester of data too. I learned my skills over a long working life, especially in survey research, where the reliability and validity of data, and the importance of good statistical understanding, were key to knowing anything.

            My approach to global warming has been pretty straightforward. What are the data, how good are they, and what do they tell us? Global warming is based on temperature data from thermometers, and since 1979, from satellite instruments from which researchers infer temperature. The global data are from 1979 on, and I have some confidence in them. Sea surface temperature measurements are just awful until Argo, while land temperature data are affected by siting, sparseness and adjustments that may be justifiable but are rarely explained and always seem to increase the trend of warming. I doubt that those earlier than 1950 are worth much just because of their small number. Ice core measurements have a variety of problems.

            I’ve looked hard at all this stuff and its rubberiness is deeply worrying. That the earth has warmed over the 20th century may be true, but we have only a poor grasp of how much. Radiative transfer physics tells us that, other things being equal, a doubling of carbon dioxide in the atmosphere will produce an increase in global temperature of about 1.1 degree C. I accept that.

            Is such an increase bad for the planet? All the evidence suggests that so far if there has been warming, it has been beneficial to the eco-system. That it must be bad is the work of computer models, which have not been verified or validated, and which don’t seem able to predict the temperatures that we have recently had.

            In short, I remain to be persuaded. I do know a lot of scientists, and have worked with them. What you call a ‘scientific consensus’ is no more than a lack of pointed disagreement, which you will find all over science. People shrug, and get on with their own work. A lot of scientists will have serious doubts about the worth of other people’s work, but they don’t pick fight with them — that’s more characteristic of the social sciences and humanities, where serious critique is part of everyone’s training.

            The Cook study of 12,000 or so papers is being verified by others, and I’ll wait until that is done before entering into the lists. But I’ll go off and find a source for you to consider.

          • glentonjelbert says:

            “Since I’ve had many years of experience in the world of peer review, I don’t talk it as seriously as you do”? A strange statement, that implies some assumptions that may be questionable.

            Cook’s paper shows similar results to other similar reviews. It assesses the abstracts, which are a matter of public record, and also gathered the assessments of the authors of the papers. You say you’re waiting for the work to be verified by others, but presumably you mean you’re waiting for someone to pick a hole in it that will allow you to maintain the view that nothing need be done? After all it was peer reviewed, it agreed with the results of at least 2 other peer reviewed papers, and all of the information that was assessed is in the public domain and available for scrutiny. So if you were to decide right now, you’d presumably have to align with its views, at least in the sense that this is the best information we have currently. Deciding to wait, is a decision. And it’s a decision that goes against the best current understanding.

            The funny thing is that the decisions that are being asked for, are decisions that make sense from the perspective of sustainability and energy security anyway. So waiting for verification looks an awful lot like digging your heels in. Since you’re a classics person who likes stories, perhaps I can refer you to the story of Cassandra…

          • Don Aitkin says:

            I don’t know why you think what i wrote is strange, and you misquote it, providing ‘talk’ instead of my ‘take’.

            The fact that Cook’s article has been published says nothing very much. The real test is what happens in the literature after it. Peer review approval is only the first step in the growth of knowledge, and any halfway able editor can always find reviewers either to support or to deny publication.

            Others are replicating Cook’s project, and replication is a good test. If you want to follow the process (I don’t), go to WUWT and search for ‘Brandon Shollenberger’. I’ve read scores of papers now and hundreds of abstracts, and global warming or climate change are key words for what so often seem to be about something else (e.g. the ‘bees’ article I wrote about the other day. But the authors know that putting in the key words is a great help in attracting attention and approval. When that stops, as I expect it will in time, the key words won’t work any more in a positive way.

          • Don Aitkin says:

            Oh dear, more haste less speed…

            ‘so often seems’

            ‘the other day).’

            And ‘i’ in the first line should ‘I’.

          • glentonjelbert says:

            Hi. Apologies for confusing your responses, Don and Peter. I’ll try to note more carefully who wrote what. I was responding on a phone while waiting for my son to go to sleep, which is probably not the best setting.

            Anyway. Peter Kemmis, I believe you’re saying that you don’t believe that CO2 causes an increase in temperature, but rather the other way around. While Don Aitkin is saying that basic radiative physics shows that there’s a 1.1C increase from doubling the CO2 (and implied is that climate sensitivity is low).

            So, firstly, scientists are aware of these arguments and do not accept them for reasons which are quite robust (though perhaps Don Aitkin will join me in trying to convince Peter Kemmis that CO2 does cause an increase in temperature, while Peter Kemmis will join me in trying to convince Don Aitkin that climate sensitivity is higher?). There are plenty of papers on the subject, and the information on both arguments is readily available, and relatively accessible.

            But to spell it out a bit. Previous climate change events have occurred because of changes in the Earth’s orbit around the sun, which affects the amount of seasonal sunlight reaching the Earth’s surface. In the case of a warming event, as ocean temperatures rise, the oceans release CO2 into the atmosphere. In turn, this release amplifies the warming trend, leading to yet more CO2 being released. In other words, increasing CO2 levels become both the cause and effect of further warming, a classic positive feedback mechanism.

            In the case of the current warming event, it is being caused by humans dumping a bunch of greenhouse gases (which is why it’s much quicker this time around). And similar to previous warming events, there are plenty of positive feedback loops to increase the sensitivity. Previous ice-ages actually demonstrate a history of high climate sensitivity, which appears to be Don Aitkin’s major bone of contention. Now there is uncertainty around exactly how much sensitivity the climate has, but the ranges indicate that there is cause for concern.

            By the way, as a complete aside, I’ve seen people taking issue with calling is a greenhouse effect or a greenhouse gas. But glass allows visible light through, while reflecting infrared light, so the analogy is apt. Glass does is by reflecting, while greenhouse gases do it by absorbing and re-emitting in a random direction, so some is sent back down, which is conceptually the same as reflection.

          • Peter Kemmis says:

            Hi Don

            I followed your suggestion; here’s one link:

            I find there’s more interest in some of the comments rather than in Shollenberger’ own post, especially the quotation of Cook’s emails about the planning of the project. But I do take my hat off to the speed, perspicacity and accuracy of the reviewers. What an astounding result!

          • Peter Kemmis says:

            Hi Glenton

            I’m really replying to your prior one to me, but I’m keeping this in seqence so the thread is maintained. Thank you for your little story – it’s a good one that well illustrates the point you are making about authority. It is on this point that we must agree to differ. I am not satisfied that the authorities on whom you rely have sufficient evidence for their conclusions. This is anathema to you, I quite understand; but I have provided earlier some examples of where their models and predictions have not been matched by observations.

            Of course, as you commented in another conversation nearby, it is frustrating when the media distorts what the scientists have actually said. You’re probably aware that the UK Guardian turned a forecast 1.2 metre rise in ocean levels from melt of Antarctic ice into a 4 metre loss (and that’s what I heard on Australia’s ABC radio also – I don’t know whether the time scale of 200-1000 years was also reported). This mis-reporting is sloppy, and the papers’ authors must get very peeved; it doesn’t help their credibility either. Perhaps a few stinging rebukes to the journalists concerned might help. It is also important that any press release they might issue, is carefully expressed to minimise the chance of sensationalism.

            A was chatting with a few friends today about the process of peer review. It arose early in the 20th century, as the field of knowledge expanded, with more and more papers. The task grew beyond the expertise of a journal’s editor, so now as we both know, new submissions are passed to relevant experts in the field concerned. This is really the extent of the peer review, although the more citations that paper might receive over time may appear to reflect greater review. It may not, of course; it may be cited simply because some of its findings are relevant.

            In our discussion today, it was pointed out that every field tends to develop an orthodox view, views that over time. So a paper that does not fit with the orthodox of the time, might be passed over, even though it may be actually very useful, as much as anything because it presents a contrary view. I suspect this may be part of the reason for Don’s caution about the significance of peer review.

            Another issue you have raised is the “precautionary principle”. Given the AGW predictions, should we not take action in any case, because the risk of not doing so is too great? We might indeed do so, were we certain about the cause, or where the measures we took were reasonably affordable and feasible. (I give you the CFCs and the ozone layer as an example, where a substitute to CFCs is now used.) I argue strongly against taking action, for two reasons: the causes and direction of climate change are not sufficiently well understood, so targeting carbon dioide emissions could be quite pointless; my second reason is that we need to provide the world relatively inexpensive energy. To keep the coal in the ground at present would condemn one and a half billion people to remain in grinding poverty, at levels well below severe poverty in the western world. I think that is unconscionable. (My own view is that we should be developing nuclear energy using thorium for example, but meanwhile, let’s work with uranium so that eventuially it replaces much of coal, oil and gas use. This is another issue, which perhaps we can discuss at another time.)

            My final point is brief – about the ARGO floats. Yes, I do set store by them, because what else have we got to work with? They do capture and report quite a lot of information as you know, and as I’ve said, it’s the observations that are critical. If heat is going into the oceans, with 3000 of them, we should be in a position to detect that, rather than just guess. Similarly, I rely on the atmospheric temperature data (now increasingly accurate), and on the data on ice mass and extent from the GRACE system.

            Now to some questions for you: I have earlier asked for your thoughts on what might lead to ice ages and inter-glacials. The new question is about what may have been the causes for the Roman and Medieval Warming Periods, and the erlier Minoan one? Any thoughts on those?

          • glentonjelbert says:

            Hi Peter Kemmis. As you know, my thoughts on the issue aren’t worth anything. But there are papers about this which are readily available. There’s actually a well known contradiction in your arguments here. Firstly, you say that radiative physics gives you 1.1C, ie climate sensitivity is extremely low. Then you point out all these phenomena (ice age and MWP) which require that climate sensitivity must be low.

            I could also ask why you ask? The analogue of your argument would be something like this: the black death killed lots of people. World War 2 killed lots of people. Therefore world war 2 was a natural event. Clearly this is a logical fallacy. My understanding from the literature is that the MWP was not as warm as it is currently, and was caused by high solar activity and low volcanic activity, neither of which apply now, even though it’s warmer now.

            Apologies for the typo when quoting you. I meant take of course.

          • Peter Kemmis says:

            Hi Glenton
            A couple of minor points: I think you may have confused one of Don’s comments with mine, in relation to the typo (and I make many of them!), and the 1.1C figure in relation to climate sensitivity.

            Perhaps this confusion has led to your thinking I’m saying “all these phenomena (ice age and MWP) which require that climate sensitivity must be low”. I don’t yet see the evidence that higher CO2 levels cause higher temperatures; rather, I see that higher air temperatures are followed by increasing CO2 levels, which makes sense to me given the lag in warming of the oceans, and the major role of the oceans in the exchange both ways of CO2. So as the oceans warm, they release more CO2, and the lag between that release and the preceding temperature rises is around 800-1000 years. We’re around 800 years after the Medieval Warm period, I notice.
            I haven’t yet examined the proxy CO2 data for ice age periods. Anyway, does the above clarify what you saw as a contradiction on my part? If not, would you explain your point some more?

            I think you are right that the MWP was not as warm as currently, although my understanding is that the Roman Warm Period was at least as warm. You may recall (not as an eyewitness, of course), that our history tells us that Hannibal crossed the Alps with elephants. There is more hard historical evidence than that, in terms of levels of Roman baths etc, so we’re not wholly relying on proxies.

            Yes, I’ve wondered recently quite a bit about solar activity, especially after reading Vahrenholt and Luning’s “The Neglected Sun”. I had no idea there are so many solar cycles; you may already know this, but there are six. I first learned about sunspots and the approximate 11 year cycle when I was in primary school, but I didn’t know there’s another cycle about every 1000 years, and another at around 2300 years. Also, I find Svensmark’s work on cosmic rays very interesting, especially in their potential role as aerosols. That brings us to clouds, and their apparently conflicting activities in both warming and cooling.

            But I think we may have misunderstood each other somewhere, because I am at a loss to understand the analogue in relation to what I asked or said. Would you please explain this further? I was simply asking what might have caused those two warming periods; if the cause is other than rising CO2, that indeed does not prove that the current warming is therefore not through rising CO2. If that had been your inference, it was not my intended implication. Where I think it is relevant is that the answers can help us look for additional potential causes, and examine them as well.

            Finally, I must take issue with your statement about yourself “my thoughts on the issue aren’t worth anything”. They are certainly worth sharing and discussing. Our extended conversation here is testament to that, and I appreciate the effort you are taking.

          • John Morland says:

            Hi glentonjelbert

            Could you please tell us the wavelength of this IR that bounces around and some of it reflected back towards Earth.

            IR ranges from 0.8 to 100 microns. Surely it cannot be across this wihole range, perhaps its just a couple of micron bandwidth. I have asked this question at various climate public awareness sessions but have yet to receive an answer.

            If you do know please inform us so I can apply Wien’s Displacement Law to calculate the equivalent black body temperature where its peak radiation output equates to that particular IR wavelength.

            With this info we should be able to assess whether this reflected IR is a problem or not for our climate.

          • glentonjelbert says:

            Hi John Morland. Thanks for your question.

            Firstly, please note that greenhouse gases act like white bodies, not like black bodies. They are reflecting, which is very different, so Wien’s Displacement Law does not apply.

            The information you request is readily available online, and I will share it below, but first I must caution you that the calculation you describe would be a dramatic abuse of Wien’s Displacement approximation. In this situation, the Earth is the black body, while the greenhouse gases are reflectors over particular wavelengths. Your calculation would assume that the GHG is behaving like a blackbody, but something that reflects is the opposite of a blackbody!

            So, no, this information will not help you assess whether the reflected IR is a problem for our climate. There are simple calculations to do this. I linked to one elsewhere, but if you want to do a simple calculation that you can verify go here:

            It’s a little more complicated than Wien’s Displacement Law, but note that Wien’s Displacement Law is simply talking about the peak radiation from a black body. GHGs are not a black body.

            Here is a very good and accessible summary of the situation:

            In particular, refer to the second diagram, which has the data you’re looking for. Earth’s IR ranges from 5 to 100 microns. CO2 reflects a range centred on 15 microns. Ozone reflects a range centred on 10microns. Water vapour acts over a broader range. To do the (invalid) wien calculations on this, you could go to wolfram alpha ( It would show that were CO2 a blackbody (which it is not), it would have a temperature of -80C. This nonsensical result demonstrates the danger of plugging numbers into formulae without a firm understanding of the conditions. In this case, that GHGs act like reflectors (white bodies), not black bodies.

    • Peter Kemmis says:


      It’s very pleasing to read another commenting on these threads, so welcome.

      Would you mind explaining why you consider “there’s no doubt that more energy is coming in than going out, right? So that energy is going somewhere… ” ? If you could just settle that little question for us, it would save a lot of angst.

    • Peter Kemmis says:

      Ah, the 97%, glentonjelbert . .

      It’s a very persuasive percentage, and more than one paper presents that figure. I’m sure you know the Doran and Zimmerman case, where the views of over 10,000 scientists sought, with about 1/3rd responding. That number was selected down to 77 each of whom considered he/she had over the preceding five years published >50% of their papers on climate science. Of that 77, 75 agreed with both of the two statements of the questionnaire, which I paraphrase here: Has the world become warmer since 1800? If so, has human activity been a significant cause? Hence the 97% consensus, on the basis of that narrow selection and very superficial questions. The Oreskes and Cook papers have been dissected elsewhere, so I’ll leave you to find those references should you choose.

      Far from all scientists support the current consensus. I’m not at my home base at present to give the reference, but there was an open letter signed by some 30,000 scientists some years ago, disagreeing strongly with the IPCC arguments and conclusions about AGW and CAGW. Early this year, a panel of the American Physical Society sought the views of three sceptics and three “warmists” (see ). Five years ago the APS had come out with a strong supporting statement of the AGW theme, provoking strong criticism from some members. Hence this review where they take such notice of those three misguided sceptics, whom one would have thought would have retreated by now in the face of all the evidence you yourself find so convincing. You may enjoy reading the transcript – I think it’s only a couple of hundred pages.

      And now, a diversion into anecdotes, if I may. In the 1970s, we were being told authoritatively that we were heading for a distinct cooling, perhaps an ice age. Separately, we were told that the world was becoming over-populated, and we would run out of food. (e.g. Ehrlich’s “The Population Bomb”.)

      When I was a kid, the consensus view about one’s appendix was that if it was at all likely to become a problem, it should be removed. Ditto with tonsils. And my mother’s generation were considered lucky if their fathers could afford to have all their daughters’ teeth removed, and replaced with these new beaut dentures that would never decay. So Mum and my aunts received that as a wedding present from Grandad. Yep, I’m all for consensus.

      I’m quite prepared to tilt at windmills, but there’s a lot of scientific reasoning behind my stance.

  • margaret says:

    As a member of the general public I find this debate exhausting. What I am grateful for though is that there are skeptics of the AGW and CAGW case in particular, because it’s all too easy for those of us who don’t interrogate the science to nod to global warming as the cause when the latest weather report of the warmest autumn in however many years is delivered on our nightly news (weather, once a supposedly boring topic needed a young woman of exceptional attractiveness to make it more interesting on our television screens but has now become a hot topic in its own right, with or without the loveliness factor of its presenter).
    I’m more circumspect about jumping to the conclusion that our grandkids are doomed because we have destroyed the planet etc., and I thank the skeptics on this forum for that (even though those peaks and troughs on the graphs remind me of the patient attached to the heart monitor having alarming palpitations or flatlining). A metaphor for the health of the planet perhaps. I’m not taking AGW at face value anymore or making assumptions based on the way ‘climate change’ is presented to us through the mass media, but I’ll let the experts read the reports and interpret the graphs.

    • Peter Kemmis says:

      Hi Margaret

      I’m really impressed; you stand out as a sensible agnostic on this matter of AGW. Thank you for taking the trouble, and thank you for your balance. And given your encouragement, I’ll try to avoid flatlining.

      In a comment you made elsewhere, you raised the question “what is the point?” The question goes to the heart of why the AGW debate engages me so much. it is not simply an academic exercise; were that so, I have far different matters to interest me. Climate science as it is called, is not my field, but it has come to affect all in the western world. And not just in the western world. The strongest advocates of CAGW urge us to “leave the coal in the ground”; James Hansen describes coal trains as “rivers of death”.

      The major influence for lifting people out of poverty is available and affordable energy. That’s what gave us the Industrial Revolution. It was a harsh revolution, no doubt about it. I remember as a child standing in front of those dioramas in the old Science Museum in London, horrified that boys of my age could be down in those Welsh mines, a life of back-breaking work in near darkness, choking coal dust . . . the scene that we know is not too far removed from what we know of mining in some developing countries. But it is a case of communities lifting themselves out by their bootstraps, and affordable available energy is a vital ingredient.

      So in 2014, what is an immediate substitute for coal to be? On a mass scale? And affordable? And available? Leave the coal in the ground? Leave one and a half billion people condemned to abject poverty? Must have a good reason.

      So that’s one side of what I see the point to be.

      The other is, what is really happening? Do we have catastrophe looming? If we do, what is the real cause? And if we know the real cause, can we address it? Anyway, I’ve been addressing those questions elsewhere, so no need to repeat ad nauseum.

      If you want a bit of fun, and some perspective, look up on your ‘favourite search engine’ the subject of “failed climate change predictions”. Quite enlightening, and perhaps helps make this other part of my point.

      All the best. Bought a smoked hock today, now in the slow cooker. Pea ‘n ‘am fer termorrer! Thanks for reminding me.

  • Margaret says:

    I also think that there’s a responsibility factor in issues of consequence like ‘climate change’ – a willingness to engage that can only happen if the experts in the field can communicate the results of scholarly research to as broad an audience as possible.

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