“The time has come” the Walrus said

“To talk of many things:

Of shoes, and ships, and ceiling wax

Of cabbages and kings

And why the sea is boiling hot

And whether pigs have wings”

Lewis Caroll, The Walrus and the Carpenter from Through the Looking Glass and What Alice Found There, 1872

My wonderful mother brought a short piece from The Australian to my attention this week. Using a segment called The Soapbox: Reader’s Wisdom[1], Mike O’Brien of Mandurah WA disclosed his own natural sciences background. He then had the temerity to liken climate scientists to ostriches, implying they have their heads in the sand, unwilling to look at things that worry them.


Finally, he posed “three simple questions” for the scientists, and said he will feel a lot better when they are answered. These questions got my Mum thinking, and she asked me for the answers. Because my Mum is a deeply caring person who wants to be informed on such matters, I was happy to oblige her with a detailed response.

For those who only come here to talk nuclear power, I assure you we will resume our usual programming soon. But I thought this article was worth posting here in the lead-up to the upcoming panel session Dealing with Denialism, in which I am playing a role. I have first given my responses to Mike O’Brien’s questions. After that, I’ve done a bit of analysis on the type of denialism that is evident in this article. Sticking with O’Brien’s animal kingdom theme, I’ve labelled this “Queen Bee Denial”.

Question 1:“What were the natural forces that warmed the planet during the Medieval Warm Period about 1000 years ago, when temperatures rose at least as fast and as much as now, because it wasn’t due to humans burning coal back then?”

The assertion that “temperatures rose at least as fast and as much as now” is the lynch-pin for the first two questions. We are talking about 800- 1,000 years ago so it goes without saying that we don’t know exactly what the temperature was or what was happening at the time. But the very first (1990) IPCC report included this simple chart.

This suggested that around 800-1,000 years ago it was as warm or warmer than today. It is based on the work of one scientist (H.H. Lamb) that focussed on mainly northern Europe and particularly central England. It was perfectly good science at the time, but the IPCC identified this important issue as requiring additional work to provide more certainty at a global level. Climate deniers love this chart.

Some of this additional work was done my Mann et al in the late 1990s and has been further developed since then. It produced more nuanced charts like that shown below, which I have lifted from a presentation by Michael Mann in Edinburgh in 2010. A very similar chart can be found in the latest round of IPCC reports (2007). Climate deniers hate these charts. It is considerably more complicated to look at than the first but actually pretty easy to follow, so stick with me.


The solid black line on the far right represents instrumental temperature recordings, surrounding which there is minimal dispute (unless you are Nick Minchin). They go back to about 1750 when the recording began. All the coloured lines are known as a “proxies”: not actual temperature data, but some other data from which scientists infer temperature (coral growth, lake sedimentation, tree rings, that sort of thing) drawn from a larger network of locations across the northern hemisphere. Each different coloured line is a different proxy. They are reasonably consistent with each other, but not perfect. Taken as a group, a likely range of temperatures can be inferred, shown as the blue shading.  The proxies do collectively pick up to infer a warmer period around 1000-1200 AD. But as Mann’s caption states, “the most recent warming is without precedent for at least the past millennium”.

So it’s clear that, contrary to the premise of the question, to the best of our knowledge northern hemisphere temperatures on the whole are higher than the temperatures in the 1000-1200 AD period. By working from a flawed premise, we get a misleading question that plants doubt in the mind of a reader. That’s denialism at its best.

When climate deniers are presented with Mann et al’s research, many will say that it has been discredited. This is total rubbish. The implications of this work for climate denial in general was clear, and the work was heavily critiqued, discussed and attacked until the US congress requested a review of the work by the United States National Academy of Sciences (NAS). In 2006, the NAS said in their review:

The basic conclusion of Mann et al. (1998, 1999) was that the late 20th century warmth in the Northern Hemisphere was unprecedented during at least the last 1,000 years. This conclusion has subsequently been supported by an array of evidence that includes both additional large-scale surface temperature reconstructions and pronounced changes in a variety of local proxy indicators, such as melting on icecaps and the retreat of glaciers around the world, which in many cases appear to be unprecedented during at least the last 2,000 years. Not all individual proxy records indicate that the recent warmth is unprecedented, although a larger fraction of geographically diverse sites experienced exceptional warmth during the late 20th century than during any other extended period from A.D. 900 onward. Based on the analyses presented in the original papers by Mann et al. and this newer supporting evidence, the committee finds it plausible that the Northern Hemisphere was warmer during the last few decades of the 20th century than during any comparable period over the preceding millennium.

They do go on to state that beyond four centuries ago, confidence diminishes and that Mann et al were a bit too bullish in their conclusions where they talked about the “warmest decade in 1,000 years” (Probably a fair call from the NAS: I can’t see how Mann et al could know to that level of detail).

So the answer to the first question is that the question itself is wrong. It is almost certainly warmer today than it was in the medieval period. I’m sorry the answer is not quicker but this is how responsible science communication works: it talks in terms of ranges, confidence levels, that kind of thing, and only rarely in absolutes.

Question 2: “What proportion of the warming of the last 150 years has been due to those same natural forces?”

Since the premise of his first question was wrong, the second question doesn’t completely make sense, but I understand what he is after. The IPCC gives us a crystal clear response, reproduced below:

Most of the observed increase in global average temperatures since the mid-20th century[2] is very likely due to the observed increase in anthropogenic GHG concentrations [very likely is defined by the IPCC as greater than 90% confidence]. (IPCC 2007 Synthesis Report pg 39)

To provide a confidence level of greater than 90%, the IPCC exhaustively reviews the relevant literature to determine whether the warming could be from natural influences. So the answer to question two is this: it is considered a 9/10 chance that most of the warming from the last 60 years has been human-induced. You’ll see this mid 20th century upturn in temperature in the chart below from the Hadley Centre. The blue line shows a rolling 11-year average of temperature; this is a more sensible way to infer a trend in something as chaotic as climate than looking from one year to the next. The trend from 1950 to today is one of strong and unmistakable warming.


Question 3: “Which computer model do climate scientists rely on for their 100-year projections, and has it been independently audited to make sure it fits the historical data as well as future forecasts?”

Again, the premise of this question is flawed. There is no single model. The IPCC findings draw on 23 computer-based models, each developed by a different scientific organisation/ university / group of very smart people around the world. The IPCC uses the findings of all the 23 models to provide  potential ranges of temperature projections for the coming century based on different scenarios of greenhouse gas emissions, and then identify a “best estimate” within that range. You end up with findings like “2.4-6.4 degrees of temperature rise by 2100, with a best estimate of 4 degrees” if we don’t cut greenhouse gas emissions, sharpish.


The chart above, taken from the IPCC Synthesis Report (2007 pg 46), shows this. The different lines are not representing different models, but temperature change under different scenarios of greenhouse emissions for the coming century. The text accompanying the figure in the report tells us that the solid lines are “multi-model global averages” i.e. there is not one single model in use. It then says “the bars at the right of the figure indicate the best estimate (solid line within each bar) and the likely [their emphasis] range for different emissions scenarios” (pg 46). This likely range encompasses all the models.

As for checking for whether a model can replicate past conditions, this is the primary means of determining whether it is any good in the first place; this is done as a matter of course when making the model. Helpfully, the IPCC tells us how the models have performed since 1990:

Since the IPCC’s first report in 1990, assessed projections have suggested global averaged temperature increases between about 0.15 and 0.3°C per decade from 1990 to 2005. This can now be compared with observed values of about 0.2°C per decade, strengthening confidence in near-term projections (IPCC Synthesis Report 2007 pg 45).

The process of using so many models together is also a very useful check for whether they are any good; obvious outliers can be identified. All of this work also needs to pass peer review before being published. Publication in peer reviewed journals is a highly competitive business, they don’t let any old rubbish slip through. The checking has been done, and done again, and done again.

I hope you agree that these questions are well and truly answered. Let’s now look at the denialism on show itself.

What we see here I call the Queen Bee approach to denialism. It is not a direct attack or refutation of the science with alternate views. It is instead a faux-sincere seeking of information by individuals with the expectation that others should scurry and bring them what they need. Queen Bees reject the notion that they need to lift so much as a finger for themselves, insisting instead that the burden lies on others to actively convince them to the level of their own satisfaction.

The Queen Bee is continuously surrounded by worker bees who meet her every need

The author of this Soapbox piece talked up his science background. He could have found these answers in about the time it took him to draft the 450 word piece. Instead of finding answers, our Queen Bee posed three poorly premised questions in a national newspaper, planting doubts in the minds of others as he went. The issues he raised were far from new; they were either non-issues in the first place, or comprehensively resolved over a decade ago. I am far from the first person to put honest effort into answering these type of questions, but they keep on being asked. Every reference I have used is publicly available and just a few clicks away on the internet. Those three short questions have taken me nearly five pages and four charts to responsibly answer. This is a fact climate deniers exploit endlessly. They know it only takes 20 seconds to lie, but 20 minutes to explain why it is a lie. Responsible scientific communication can rarely be done in sound bytes. But Queen Bees feel entitled to voice doubts in the most public of forums, with no associated sense of responsibility to crack the cover a report and learn for themselves.

A lay person with an inquiring mind about climate change science is a great thing, and it should be encouraged. Sincerely posed questions should be answered. But the sense of inquiry needs to be distinguished by at least some effort from the enquirer, otherwise it risks quickly morphing into the lazy, vexatious nonsense of Queen Bee denial.  If people wish to participate in the science conversation beyond accepting the consensus findings, at some point the onus must shift to them to do a bit of work in reading a report. Pontificating in public forums as though there is something deceptive going on is not a sincere search for knowledge; it’s poorly disguised denialism, whether the pontificator realises it or not.

My Mum genuinely wanted the answers to these questions so she came to me. Queen Bees don’t want the answers, they want others to read their questions. If they wanted the answers, they would have heard them the first time…

“It was so kind of you to come!

And you are very nice!”

The Carpenter said nothing but

“Cut us another slice:

I wish you were not quite so deaf

I’ve had to ask you twice!”

Lewis Caroll, The Walrus and the Carpenter from Through the Looking Glass and What Alice Found There, 1872

Illustration by John Tenneil, found at The Victorian Web http://www.victorianweb.org/art/illustration/tenniel/lookingglass/4.3.html 

Thanks also to Greenman for the Climate Denial Crock of the Week video series. Find them on YouTube

[1] “Love or hate something passionately? This is your space to get it off your chest”. To the whole nation, whether or not it relates to an issue of critical importance, and whether or not you are right or wrong.

[2] Prior to about 1950 the influence of the additional greenhouse gas was not strong enough to really stand out from the ongoing variances in climate from decade to decade.


  1. I have just finished reading “Why Geology Matters – Decoding the past,Anticipating the future” by Doug MacDougall,Professor Emeritus of Earth Sciences at Scripps Institution of Oceanography,University of California.
    MacDougall,although trained as a geologist,describes the history of the whole Earth system from the Hadean eon to the present.He does this in a very readable manner and I commend it to anybody interested in our Spaceship Earth.
    In relation to your article,what comes across from this book is the extreme variability of climate from a very early time.It has been much colder and much warmer than at present and MacDougall states the various forcings which are thought to have caused this variability using the available scientific evidence.
    There have been 5 major extinctions during our present eon,the Phanerozoic, which began about 540 million years ago.One was thought to have been caused by an asteroid collision.The others were likely caused by massive volcanic eruptions over a long period.Now,we are in another major extinction which is entirely human caused.It is up to us to rectify this state of affairs if only for selfish reasons as we could be one of the species on the extinction list.

    As for deniers,you are spot on the mark.These people are not amenable to reason because the views they hold are part of an ideology/religion.In other words they have faith based views which are remote from reality.Some of them are engaged in proselytism which is typical of that mindset.
    I prefer to ignore them and just try and get on with the job of helping,in my own small way,to effect the necessary change.Ignoring them may not be possible for somebody in your position,Ben,and you have my sympathy.

    1. Thanks Podargus. I certainly try to keep my powder dry and don’t go there too often, but my new approach is to identify the behaviour rather than point out the lack of scientific reasoning. Hence the Queen Bee label, which will hopefully help me and others short-cut a few ridiculous conversations.

  2. The other red herring with the Medieval Warm Period is hiding in plain sight: My impression from the recent literature is that it’s looking more and more like a local (i.e. not even the entire Northern Hemisphere, just certain parts) phenomenon, not the ‘planetary’ warming premised in the question. http://www.skepticalscience.com/news.php?n=98

    1. Indeed. The presentation by Mann that I nicked the chart from makes this point, adding that some discreet locations may indeed have been very warm. You can find his presentations from his web site.

      1. Interesting article. The work by Mann et al draws on a global network of nothern hemisphere proxies, so it does suggest a global upturn around that time. Not sure if any of the data relates to Andean regions specifically. However his conclusions infer that unlike the global temperature change, the localised impact in northern Europe was more pronounced.
        Here’s a couple of key quotes that I was referring to in my reply to Mark Duffet:
        “Recent hemispheric-scale warmth anomalous in at least a millennial context; can only be explained by anthropogenic radiative forcing”
        “Medieval warmth in high-latitude North Atlantic and parts of North America rivaled modern warmth”

    1. Not sure how Mum went… only sent her the link today! 🙂

      Gish Gallop will get a good run on Monday, since it was born in Creationsim, one of topics we will be covering.

      About to look up Concern Troll

  3. The models used by the IPCC all have levels of uncertainty which, although now less than those initially used, are still such that, when calculating the net difference between downwelling and upwelling radiative flux at TOA the uncertainties (error bars) compound to yield uncertainty in the result which is over 2%. Now, measurements show that the net flux rarely fluctuates outside the range of +0.5% to -0.5% of total incoming solar insolation. But the uncertainties yield error bars well above 0.5% in magnitude and so the models cannot establish whether the net result is actually positive or negative. Hence one cannot conclude that the world should warm from the models, and indeed it has not done so since 2003, as the (annual) mean sea surface temperature for the 12 months ending September 2011 is actually less than the annual mean SST for the 12 months ending December 2003. (Anyone can see this from NASA data.)

    There have been more papers published since 2006 indicating similar temperatures in the MWP. But the actual magnitude of such temperatures is not critical to the argument that natural causes have produced some variations in climate in the past. There is no reason to assume that the amount of thermal energy generated in the Earth’s core, mantle and crust will be perfectly uniform for thousands of years. Any variations could potentially alter the temperature at the surface over the course of decades or centuries.

    There are other potential anthropogenic causes also, most notably underground nuclear testing at about 2,000 sites late last century when the warming was at its steepest. Such tests caused damage to the crust and produced cavities underground and under the floor of the ocean. This enables thermal energy which originated deeper underground to escape more readily (and thus undiminished) and so gradually warm the surface and oceans. The flattening of the temperature gradient early this century may have been due to gradual natural repair of such damage, for example, cavities filling with clay or sand.

    Greenhouse gas molecules are mostly the only ones which radiate thermal energy and thus cool. Oxygen and nitrogen molecules would remain much hotter but for the fact that they collide with GHG molecules like carbon dioxide and shed some of their thermal energy. Thus carbon dioxide can also have a cooling effect. And even if a carbon dioxide molecule is temporarily warmer than surrounding molecules, it will either emit a photon or distribute its extra thermal energy by diffusion among about 2,500 other molecules, by which time any temperature difference will be negligible.

    The atmosphere only holds about 4% of the thermal energy above the crust. Roughly 90% is in the oceans and sea ice. So any warming of any significance has to happen in the oceans. Indeed local oceans do warm in local summer, but they also cool in winter. So what is the carbon dioxide doing while they are cooling? Nothing. Just like a pot of water on a stove, the temperature of the crust regulates the ocean floor temperature (like the stove element) and this determines the base ocean temperature in local winter. The sun only causes temporary warming each day and each summer. All such temporary thermal energy ends up escaping back to space. The sun does not warm all the Earth system under the surface where, even at just 9Km depth, German borehole temperatures were about 270 deg.C.

    No published peer-reviewed paper has ever proved any of the above incorrect.

    1. And you have never published any of the above in a peer reviewed paper, so pray tell, what is your point? Until you do, you are just ranting Doug, subjecting yourself to no one of acceptable qualification to review your work.

    2. “Models are unreliable” Models successfully reproduce temperatures since 1900 globally, by land, in the air and the ocean.

      “It hasn’t warmed since 1998 (or 2003, whatever)” For global records, 2010 is the hottest year on record, tied with 2005.

      “Climate’s changed before” Climate reacts to whatever forces it to change at the time; humans are now the dominant forcing.

      That’s all I can be bothered covering at this late hour. For more responses based on actual, peer reviewed, scientific papers, go to:

  4. We need a Skeptical Science type, argument/answer site for nuclear power. It just makes late night commenting so much easier.

    (…when I can make the damn links work that is. Aaaaargh)

    1. Hey Marion, this all started over at The Conversation in a thread on an article about meat eating. Doug just dumped a bit of spam over here for fun, the exact same comment can be read over there, as can my approach to him which is consistent with the presentation I gave on dealing with denials. Do not, do not, do not feel the need to waste time on this guy over here, I will expunge at some point.

  5. Trust me Ben, I have no such compunction. Luckily, this debate occurred, and was resolved, long ago. All I did was link to the result. No time wasted.

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