Okay, here's another modest proposal

You know if you’ve had more than a cursory look at this blog that I am some way along the ‘sceptical’ continuum as far as Anthropogenic Global Warming goes. But one thing I have learned is that it is not enough to complain about things, one ought to make constructive suggestions. So here goes.

If we were serious about (a) proving cause and effect as far as Anthropogenic Global Warming is concerned; and (b) trying to stop it, there is one bold action I would happily get behind.

This would be grounding all the world’s aircraft for a few years. Take all the money currently being spent on various carbon trading schemes and bureaucracies and uneconomic renewable energy schemes and give it to the airlines to pay them to mothball their machines and pay their staff to sit around doing nothing. 

The rationale for this is two-fold:

1. We have a pretty good idea anthropogenic cirrus clouds from aircraft have a significant warming effect. And the warming observed over the past half-century is localised most strongly where these anthropogenic clouds are: in the northern hemisphere, not the south; and over continents, not oceans. 

2. All greenhouse gases are not equal. When I drive my car down the Princes Highway past the towering eucalypts of Royal National Park, I know that the water and carbon dioxide bands in the atmosphere at ground level are pretty nearly saturated, so the emissions of my car will not make a great deal of difference to how much additional infrared energy is absorbed. And I know also that my car’s emissions are not going to stay in the atmosphere for long, because those aforesaid towering eucalypts and other green plants are going to enthusiastically suck them up. When I fly down to Sydney, though, it worries me. The plane I’m riding is spewing carbon dioxide and water vapour out into a part of the atmosphere that doesn’t have a lot in it already, a long long way away from any plants that can use them.

I’ve made these arguments before on this blog, but not recently. So I figured it was time for some repetition.

Stopping aircraft for a few years should give a very good idea what proportion of the observed warming is due to anthropogenic cloud and emissions of greenhouse gases at altitude, and hence whether carbon dioxide emissions per se are worth stressing over.

I think the economics of this are solid. The maximum annual profit airlines have made recently seems to be of order $30 billion, and there probably aren’t more than 4 million people who would need to be paid to do nothing, as opposed to being swapped immediately to productive jobs elsewhere in the newly frisky sea and rail freight sectors. So maybe another $100 billion paid to them. That’s less than we’ve been spending in silly ways in recent years, I’m pretty sure.

I know what you want to see: some half-arsed Climate Modelling!

The graph I showed in the last post wasn’t very good evidence for anthropogenic global warming. If I wanted to scare you, I would show you this graph instead.

This shows the correlation between carbon dioxide and temperature found in a brilliant set of data collected from ice cores at Vostok, Antarctica, where ‘0’ on the temperature axis is the average temperature for the last century or so. [Attribution to text files of raw data: J. R. Petit, J.M. Barnola, D. Raynaud, C. Lorius, Laboratoire de Glaciologie et de Geophysique de l'Environnement 38402 Saint Martin d'Heres Cedex, France; N. I. Barkov, Arctic and Antarctic Research Institute, Beringa Street 38, St. Petersburg 199226, Russia; J. Jouzel , G. Delaygue, Laboratoire des Sciences du Climat et de l'Environment (UMR CEA/CNRS 1572) 91191 Gif-sur-Yvette Cedex, France; V. M. Kotlyakov, Institute of Geography, Staromonetny, per 29, Moscow 109017, Russia]

I came to this data because I wanted to have a closer look at an assertion I have come across a number of times, that changes in carbon dioxide lag changes in temperature in ice core measurements. And yes, it does seem to, but it is a very unwise thing to base a full-blooded skepticism to global warming on. Because the lag is smaller than the uncertainty in the data. The age of the ice, and the age of the air trapped in the ice, is not the same: there is a difference of about 3000 years between the age of the trapped air and the age of the ice, which isn’t known with absolute accuracy, because it takes time for the snow and ice above a little bubble of air to be compact and impermeable enough to trap it there for good. The carbon dioxide content is obviously calculated from the air, while the temperature is calculated from the isotopic ratio of deuterium to hydrogen in the ice molecules. And the imprecision in aligning the exact times of these two sets of data is larger than the lag values that have been reported. It would be nice if this data gave a definitive answer as to how closely carbon dioxide and temperature changes track one another, but all we can say is that on a time scale of +/- 1000 years or so they move simultaneously.  I could just let you draw a line through the data extrapolating to the 400 ppm of carbon dioxide we have today, but I will do it myself.

This is a fit to the data assuming that all the change in temperature is due to radiative forcing by carbon dioxide, fixing T = 0 as 286 K and 284 ppm CO₂, with the log of the concentration change giving a change in absorption which has to be compensated by increasing the temperature of a black body radiator, with one adjustable parameter (an invariant non-CO₂ radiative forcing) adjusted to minimise the sum of the square of the differences between the fitted curve and the experimental data.

Scary, eh?

If this is the correct way to extrapolate the data, then we are about 6 degrees cooler than we should be, and are just in some sort of lag period - of some unknown length, but definitely less than a thousand years - waiting for this to happen.

I was on the brink of converting myself to global warming alarmism, but I thought I should have a look at the original papers first. Here are some great graphs from Petit et al., 'Climate and atmospheric history of the past 420,000 years from the Vostok ice core', Antarctica. Nature 399: 429-436.

Carbon dioxide is not the only thing that is correlated with temperature changes. Methane, another greenhouse gas, is correlated with temperature changes. (They did the maths in the paper, and r² is 0.71 for CO₂ and 0.73 for CH₄). The temperature changes are also closely correlated with the predicted insolation – the amount of sunlight incident on the Earth, varying according to irregularities in its orbit. Dust and sodium (a proxy for aerosols, which we know are cooling) are negatively correlated with temperature changes (r² is 0.70 for sodium). Ice volume (which is a proxy for water vapour, another powerful greenhouse gas) is positively correlated with temperature.

While insolation can only be a cause of warming, all of these other correlating things can be both a cause and an effect of increasing global temperature. We do not know, just by looking at this data, what is what. A sudden fall in dust and sodium, an increase in ice volume, and a sudden rise in CO₂ and CH₄ characterises the onset of all of the interglacial warm periods covered in this data. In the graph below I’ve fit the data again, but this time instead of adding an invariant radiative forcing by other things term have multiplied the carbon dioxide radiative forcing term by an adjustable constant to approximate the effect of all the other variables that are changing in synch with carbon dioxide. This constant turned out to be ‘41’ for the best fit, shown. So using this very crude fit, I can extrapolate the effects of *just* changing carbon dioxide concentration to 400 ppm, without any of those other things changing.(That's the line of green triangles hugging the axis from 300 to 410 ppm). This result seems absurdly Pollyanna-ish, even to me, and I'm sure I could make it looks scarier with a model for the experimental data with more adjustable parameters: but that's what the 'suck it and see' model gives me.

I've also put in the observed changes in modern times on this graph. It does make sense to attribute these to CO₂ with a little help from the other greenhouse gases we've been putting into the atmosphere. And because we're extrapolating beyond the bounds of the historical data, we may be in a strange and uncharted perturbation of the global climate system. So maybe there is still a significant lag for us to catch up with. Maybe.

But there is one other thing that emerges from this ice core data that suggests very strongly that carbon dioxide concentrations are much more an effect than a cause of global warming. Have another look at this figure:

At the end of each interglacial period, the temperature drops before the carbon dioxide concentration does. This is not a minor effect lost in the uncertainty, like the possible lag in carbon dioxide concentration at the beginning of warming periods; it is a big lag of many thousands of years. Insolation and methane don't behave like that: they rise and fall in lockstep with temperature. What this tells me is that carbon dioxide has historically not been sufficient, by itself, to maintain a warming trend. So we can completely discount any panic-mongering positive feedbacks.

Whatever

A Brief Restatement of the Obvious for a Clueless World

Item 1: The heat capacity of the ocean is big compared to the heat capacity of the atmosphere.

Item 2: The carbon dioxide capacity of the ocean is big compared to the carbon dioxide capacity of the atmosphere.

Item 3: Heat and mass transfer across the atmosphere/ocean interface are not independent and are not simple.

Personal experience re Item 3: I have spent a lot of the last six years trying to get my head around heat and mass transfer across the atmosphere/farm dam interface. 

3a: It is really not simple.

3b: Even a failed physicist like me can see that the semi-empirical models of it in the 'climate science' literature are dodgy-as.

3c: I have a model: it is too hard to test in farm dams so we have gone back to 44-gallon drums of water.

3c.i: We haven't got data good enough to test it in six months yet.

3c.ii: 44-gallon drums of water are simpler than the ocean.

Item 4: When I was an undergraduate, when we talked about the weather, we talked about strange attractors and the butterfly effect and the essential unpredictability of complex systems and the impossibility of drawing a line between weather and climate since they showed the same self-similar pattern on all scales. Now, for the entire lifetime of today's undergraduates, the world has been running around like a headless chook pretending the climate can be modelled by y = mx + b.  

Problem?

Ce qu'on voit et ce qu'on ne voit pas

Just floating a back-of-envelope calculation about ¹²C:¹³C ratios in different parts of what I am going to call the 'dynamic' carbon cycle: the bit where carbon is moving around a lot, leaving out both the slow deposition of fossil fuels and carbonates and the geological or anthropogenic processes that get them out of the ground again.

I've taken some numbers from one of many pictures of the carbon cycle available on Our Friendthe Interwebz, and shown them to scale the way the ancient Greeks would have, geometrically. The area of the arrows and the squares are to the same scale, showing the amount of carbon in each place and the amount moving from one place to another in the course of a year. There are three populations of carbon in this simplified picture: Biomass (plants and soil), the atmosphere, and the oceans. And the greatest of these is the ocean.

Note that we basically have a fast equilibrium (the atmosphere and biomass equilibrating rapidly, on the rough order of a decade to exchange half the carbon in the biomass) and a slow equilibrium (the atmosphere and the ocean doing the same on the order of a few hundred years).

Before moving on, I just want to say that the overall ratio of ¹²C:¹³C in this whole system should remain pretty much the same for periods of geological time that are long compared the time scales in which lots of interesting things can happen. Good evidence for this is that the amount of variation in carbonates laid down since the beginning of the Pliocene is not very much at all: less than +/- 1 ‰ (Ghosh & Brand 2003).

Now, the relative amount of ¹²C:¹³C in each box will be governed by two things:

(1) The relative amounts of ¹²C:¹³C in the box(es) it is in equilibrium with; and,

(2) Any isotopic selectivity in the transitions between boxes.

Now, the isotopic selectivity due to the more rapid diffusion of  ⁴⁴CO₂ over ⁴⁵CO₂ through eensy-weensy membranes in plants is very well understood: and this generates a clear difference in the ¹²C:¹³C ratio between biomass and the atmosphere, despite the rapid interchange between them.

But, if there was no life on Earth, the atmosphere would still be enriched in ¹²C:¹³C relative to the ocean. Because there is also a solid basis for isotopic selectivity in the ocean:atmosphere equilibrium. Most of the carbon in the ocean is present as hydrogen carbonate ions in the deep ocean. To get to the surface, this material has to run a gauntlet of a layer of warm water hundreds of metres thick where calcium carbonate is stable. I haven't been able to find any decent data on isotopic dependence of hydrogen carbonate ion diffusion rates - just some molecular dynamics simulations that didn't find a significant difference* - but a priori, if you have a column of fluid some hundreds of metres high, surely the bottom of the column is going to be enriched in the component with a molar mass of 62 rather than 61.

Now it seems to be the because of the fast interchange between the biomass and the atmosphere, the relative distribution of carbon isotopes between the ocean and the total (biomass + atmosphere) component has to be governed by the slow equilibrium. And thus the main driver of the isotopic ratio in the atmosphere has to be the slow equilibrium. Yes? If you see a problem with this, let me know.

So: looking back at those boxes. And going back to that number from Ghosh & Brand 2003 and some other numbers. Taking -6 ¹³C ‰ for the pre-industrial recent atmosphere and -25 ¹³C ‰ for terrestrial biomass (Epstein 1969) gives an overall value of -20 ¹³C ‰ for the (biomass + atmosphere) component. Now, if we have a ¹³C ‰ of 0 ± 0.8 for oceanic carbonates since the Pliocene, this means that the error we should reasonably associate with this component should be of order ± 10 ¹³C ‰.

This may be a conservative overestimate: but looking at the size of the boxes where the carbon is sitting, the error in the small boxes has to be bigger than the error in the small boxes. And there is one more small problem, which is that while the ¹²C:¹³C selectivity in plants is well-understood and not likely to have changed much at all since the little fellers evolved their carbon fixation pathways, the ¹²C:¹³C selectivity of ocean:atmosphere transport ought to be dependent on the distribution of the layer of warm water, which will rely on the vicissitudes of global climate and over a longer period of time how the continents are shifting about to change global ocean circulation.

So, my point is: relying on ¹²C:¹³C ratios alone to tell us details about the source of a particular carbon-containing deposit at some remote period of time is probably not a good idea, because there are likely to be big systematic errors which we know not what of.

Perhaps that's not a very big point. 

* And only just found a significant difference for CO₂, where we know one exists experimentally.

Please ... just don't

Twitter, marvellous as it is, is no good for explaining anything. And Twitter when you are cranky is no good for anything except making you look like a dill. So I thought I would come here and explain why I might get incandescent with rage at an article like this one, which includes a quote one might reasonably think I would be 100% on board with, "the rejection of science is arguably the most important social problem in the Western world". And I am - 100% on board with that sentence, that is.

But... if you are going to write an article lamenting the decline of reason, you should display some use of reason in writing your article. Otherwise, to supporters of reason, you are an unwelcome ally. You are like the local warlord who shows up in the middle of the tidy surgical strike to helpfully behead the police chief's extended family. Or the smelly unshaven hippy who shows up at the antiwar protest and helpfully starts chanting obscenities just as the TV cameras start rolling.

Okay. Mungo is impressed by Singapore. Singapore is impressive. True. Everyone who goes to Singapore is impressed by Singapore. There are things we can learn from Singapore. True. It also has the highest rate of capital punishment in the civilised world, draconian policies to keep out illegal immigrants, no political freedoms to speak of, and a social safety net that is worse than any Western country. Singapore works because it is small - and related to being small and ethnically different from its neighbours, a bit paranoid; because it has a culture of hard work; because it inherited the rule of law and some other good things from the British; and because it was lucky enough to have an authoritarian leader who was competent and principled. It is not a good basis with which to contrast a vibrant East with a decadent West.

Mungo says that overindulgence, monument building, and an increasing tendency to believe in the irrational are symptoms of a society in decline.

People in Asia who are working their way up don't have anything to overindulge with. Those who can overindulge are way ahead of us in terms of conspicuous consumption. Check out the business section of any paper anywhere. That's not East vs West, that's just people. The West is broke not because it is particularly overindulgent, but because it got rich enough to be in a position that everyone didn't have to work like dogs until they died, so we got out of the habit. At the same time we tried to spread the wealth around and give everyone a fair go, and didn't get the maths right. Similar things happen whenever people get rich, anywhere. It's all there in Ibn-Khaldun's Muqaddimat. 14th century. Check it out.

I don't know why Mungo threw monuments in there. Where are they building monuments nowadays? Nowhere in the West. It used to be the Sears Tower was the highest building in the world for a generation, now every time you turn around there is a new one in East Asia (built according to the best principles of Feng Shui) or the Middle East (built by absolute monarchs who reject evolution). Abraj-al-Bait? Three Gorges Dam? Show me anything like that being built anywhere in the West.

Finally, he gets to the bit of the article that the sub-editor thought the headline should be about, the part I should theoretically be on side with, but it is just a mess of disconnected ad hominem statements that might have been designed to press all my buttons.

But the second is far more prevalent and worrying: an increasing tendency to believe in, and rely on, the irrational. In Rome, this manifested itself in the proliferation of strange religious cults and a rejection of science which led, ultimately, to the dark ages in Europe. And the rejection of science is arguably the most important social problem in the Western world.

Is there really an increasing tendency in the West to believe in and rely on the irrational? I don't see any evidence of it. Almost people in almost all places believe in and rely on the irrational. There are plenty of indicators that could be interpreted as going the other way: for instance, the percentage of people identifying as 'no religion' in censuses. If you dig out a newspaper from a hundred years ago, you will find politicians making the same irrational arguments using rhetoric and emotion instead of logic. You will find the same quack cures and crazy religious cults. I don't see a trend. I just see people.

The dig about strange religious cults and the fall of Rome is just a cheap shot at about 2 billion people. Why would you want to get 2 billion people off side to score a cheap rhetorical point? Rome had no science to reject. They didn't have what we call science. They had engineering, they had philosophy, they had plenty of slaves to do the hard work: but they weren't a civilisation of 200 million rationalists. They were just as irrational in 753 BCE as they were in 476 CE. The official religion of earliest Rome was just as much a 'strange religious cult' as the latest heresy of Theodoric's time. Rome had lots of problems, but they didn't fall because they 'rejected science'. And by the way, technologically, the 'dark ages' were a period of continuing improvements - knitting, the stirrup, windmills, etc. Just saying.

Its epicentre is, of course, the United States, in which more than half the population reportedly rejects the theory of evolution in favour of a particularly batty form of Christianity in which an obsession with sexual morality is combined with the drug-induced fantasies of the book of Revelations, with more than a touch of astrology, numerology, iridology and you name it thrown in.

Now, I have argued a lot with Young Earth creationists. A lot. But it bugs me - probably on the purely thin-skinned basis of being of a particular cultural background - that practically the only people in the world that can be abused and slandered with impunity are the overwhelmingly goodhearted and hardworking people of American 'Flyover country'. Who have been practising pretty much this 'particularly batty form of Christianity' in pretty much the same proportions for the last three-hundred or so years. Read Mark Twain. Read H. L. Mencken. Somehow, during this time their country managed to become the world's leader in science. It is also interesting to note that this 'particularly batty form of Christianity' is pretty much identical to the religion followed by Isaac Newton. There is no trend to more irrationality here. It's just business as usual. And the 'drug-induced fantasies' dig is just another gratuitous, evidence-free statement to get 2 billion people off side. Why?

Australians have not yet gone to the this extent, but we are definitely moving in the same direction. The trend manifests itself in a variety of fringe groups – opposition to vaccination, fluoridation, and other scientifically proven public health measures is apparently on the increase.

So-called "alternative" (a synonym for untested, irrational, unscientific) medicine is embraced with growing fervour by otherwise sensible citizens.

This is okay. So far as I understand these trends exist. And I don't like them at all. Mungo also puts in the word 'apparently' once, which is a sign that he is moving towards rational argument instead of throwing down dogmatic unverified statements. Good.

Religion, already based on faith rather than reason, is becoming either totally dumbed down (the happy-clappy churches) or reinvented in ever more bizarre sects and cults involving everything from the worship of trees to the channelling of archangels.

Again, I am no big fan of the Evangelical churches. And like I said, I have argued a lot with Young Earth creationists. Personally, I agree that they are 'dumbed down' compared to a lot of other religions. But whether they are 'happy clappy' or 'unhappy unclappy' is surely irrelevant: whatever sort of liturgical practice brings a believer closer to God and doesn't involve sacrifice of kittens has to be good, if you think there is any good to religion at all. Worship of trees? Channelling of archangels? Didn't that go out with the 70s? And, isn't that the sort of thing most associated with the sort of 'Deep Greens' who are most likely to agree with Mungo on his next point... ?

And then there is the clearest indicator of all, denial of climate change.

The problem with a catch-all statement like 'denial of climate change' is that it telescopes a long and rickety chain of questions and answers into a single stick to beat your opponents with. Some of the questions are scientific questions with straightforward answers susceptible to experiment and data collection: some are social and economic questions that need to be legitimately - and rationally - debated. None of the science is as 'settled' as real 'settled science' is. All the social and economic questions are open questions. Don't trust me, I'm just some guy on the internet. Don't trust me because I'm a scientist. Look things up for yourself. Think.

In the past, this was the domain of those with a vested interest, such as coal owners, and the barking mad, such as Cardinal George Pell and shock jock Alan Jones, each of whom has his own reasons for believing in fairy tales.

Well, this has never been true. There was a wave of hysteria at a time of sharply rising temperatures that carried practically everyone away with it - briefly. I don't know anything about Alan Jones. But Cardinal George Pell has a perfectly rational, well-thought-out position on climate change that is motivated by Catholic social teaching about not screwing the poor [see Footnote]. 'Fairy tales' is another pointless dig at some billions of people.

But doubts (for which there is no basis at all) are now spreading among the general public, to the extent that Julia Gillard (and Tony Burke, when a petty-minded opposition will let him go) will appear at the Rio Summit with their own well-thought-out measures to deal with the problem (the carbon tax and their marine parks network, for starters) both deeply unpopular within their own country.

'No basis at all' is bogus. There is a reasonable, not huge, basis for doubt at the very beginning of the ladder of questions and answers 'Q1: Are human activities warming the Earth?'; and a vast raft of unexamined assumptions and an overwhelming basis for doubt by the time we get to 'Q#: What are the measures we should be employing to address this problem?' The carbon tax and marine parks network are not well-thought-out measures. There is no evidence whatsoever that they will do 2/10 of stuff all to stop the climate from changing. They are just sentimental, tokenistic, expensive measures that we can't really afford.

And Rio, of course, has already been marked down for failure: the West, in particular, is more concerned with saving itself from decline and fall than with the preservation of the planet. And yet it is precisely this selfishness, this short-sightedness, and yes, this overindulgence and irrationality, that has got us into the mess in the first place. Over to you, Asia.

And Asia is just so into controlling carbon emissions, innit? *cough* China (where the uncertainty in carbon emissions is apparently as large as the entire greenhouse gas output of Japan) isn't exactly going out of its way to 'preserve the planet' at the expense of its own economic development. Nor is India. Or Malaysia. Or Tajikistan. Or the Maldives. Or anywhere in Asia. It is just a few of the navel-gazing decadent nations of the West that are shuffling in that direction.
  

Edit 28th June: 
Footnote added, the key bit of Cardinal Pell's Global Warming Speech of 26th October 2011:
"I support the recommendation of Bjorn Lomborg and Bob Carter that, rather than spending money on meeting the Kyoto Protocol which would have produced an indiscernible effect on temperature rise, money should be used to raise living standards and reduce vulnerability to catastrophes and climate change (in whatever direction), so helping people to cope better with future challenges. We need to be able to afford to provide the Noahs of the future with the best arks science and technology can provide. In essence, this is the moral dimension to this issue. The cost of attempts to make global warming go away will be very heavy. They may be levied initially on "the big polluters" but they will eventually trickle down to the end-users. Efforts to offset the effects on the vulnerable are well intentioned but history tells us they can only ever be partially successful. Will the costs and the disruption be justified by the benefits? Before we can give an answer, there are some other, scientific and economic, questions that need to be addressed by governments and those advising them. As a layman, in both fields, I do not pretend to have clear answers but some others in the debate appear to be ignoring the questions and relying more on assumptions."

Some time ago I was asking the question: ‘How good are these climate models? What sort of predictive value have they shown in modelling future climate? After all, we’ve been doing them for a few decades now.’

A nice person on realclimate.org (there are some, not all of them treat people who disagree with them as the demonised other) directed me to a classic paper by Hansen et al.

"If you want an indication of how well these models do you can go get (J. Geo Res. 93 (1988) 9341) the Hansen GCM paper that people talk about, and compare their results with observed patterns of warming and other things."

Here is the plot from that paper showing the response of overall global temperature (which the authors argue convincingly is a much better parameter than any subset of the data, e.g., whether it snowed at my house or not in a given year) for three different scenarios- A being continued exponential growth, B being a more subdued form of business as usual, and C if drastic cuts are implemented starting a few years ago.

I went and got the Hadcrut3 data set and plotted it on top of this one, as near as I was able, and got this.

There are other data sets out there. I shall plot some of the others and put them up for you.

The Hansen et al. model predicts the greatest degree of warming at high latitudes, fitting observations, but the model also reproduces another feature of observed weather, that those latitudes have the highest natural variability from one year to another.

Update 2012:
Here is another three years of data. I do realise I haven't plotted any of the other data sets. Bad me. The red points are the average of 13 monthly data points averaged on each month, while the blue points are the actual Hadcrut3 monthly global averages you can download yourself.

In which I place myself beyond the pale of civilised discourse

Firstly, an observation on scientific models, coagulated in the enthralling world of emulsion polymerisation:

Whenever you are trying to model some complex phenomenon, the fit of the model to the data can be improved by adding more adjustable parameters. A complex phenomenon will usually be dependent on a large number of factors, but the fact that the model fits the data better when you incorporate an additional factor may or may not mean that new factor is important: it might just mean that the additional parameter(s) you have incorporated are improving your fit. This is another thing the David Sangster told me: ‘With enough adjustable parameters, you can fit a camel.’

So there is a tension between the complete model, which contains all the factors that ought to be physically important – but might be meaningless because of all the guesstimated parameters you have put in to quantify these factors- and the simple model, which ignores things that might be physically important, but also avoids adjustable parameters. If you go too far in one direction, you get a model that can fit any possible data; too far the other, you get the well-known ‘assume a spherical horse’ punchline.

This also means that when you are modelling a complex phenomenon, you will tend to base your model on the processes that are best known, where you don’t have to pick numbers out of the air for your adjustable parameters, and you will ignore if you possibly can the role played by processes that are less understood, which would force you to bring in rubbery parameters.

Now to place myself beyond the pale. Some time ago I made the assertion:

‘Anthropogenic global warming is a fact, but we shouldn’t do anything about it.’

The second part of this statement is a considered opinion, based on facts and reasoned deductions from them. The first part of this statement, I have realised over the last few months, is based on an irrational mood.

That is: in the laboratory, and considering the atmospheres of the planets in toto, there is a perfectly splendid mechanism by which increasing the concentration of atmospheric carbon dioxide should increase temperatures. It is a really good mechanism, based on rock-solid physics. But is there any evidence that this mechanism is responsible for observed temperature change globally? Evidence, in the scientific sense, is where a model has predictive value: it does not just fit the data we have, but tells us what future data is going to look like. I did not examine this question before I made the statement above. Instead, I relied on the irrational mood that it seemed like wishful thinking that there was some sort of feedback mechanism providentially cancelling out this Greenhouse warming effect.

Let us consider these two famous graphs:

What do they tell us? They show us a correlation between carbon dioxide concentration and average global temperature. They also tells us, very clearly, that there are factors other than carbon dioxide which contribute to the world’s temperature.

We could also draw graphs that show some sort of a correlation between sunspot activity and global temperature, and earthshine and global temperature, and the number of pirates and global temperature. The last of these three graphs would be a joke circulated by the Church of the Flying Spaghetti Monster. The other two are graphs where it is easy to construct a testable mechanism for how the correlation might work. These mechanisms are not as solid or as well understood as the Greenhouse mechanism. They rely on more rubbery adjustable parameters. If we ignore them, do we have a spherical horse? If we include them, do we have a camel?

What is signal, and what is noise, in the Hadcrut3 temperature curve?

An idea that was in fashion when I was an undergraduate was the Gaia hypothesis of James Lovelock. You don’t hear much about it nowadays. You might remember that it was all about negative feedbacks keeping the global ecosystem in balance, life keeping things tickety-boo for life. I bring it up here as a hand-waving justification for a recent shift in my irrational mood: given that there is a grain of truth in Lovelock’s ideas, it now seems to me reasonably likely that there would be a negative feedback mechanism tending to minimise the effects of any carbon dioxide we add to the air.

I must now revise my assertion:

‘Anthropogenic global warming is a conjecture with limited predictive value, and we shouldn’t do anything about it.’

And I have to apologise for some of the slighting references to global warming denialists I have made previously.

And unfortunately I have nerfed one of the major motivations for establishing this blog, which was to use any perceived authority associated with my real name to push the line that we shouldn’t take any action to stop anthropogenic global warming. By denying AGW to be a fact, I have placed myself outside the pale of civilised discourse and disqualified myself from making any statements on the issue that will be taken seriously.

Son cosas de la vida…

Royal Society Discussion Paper, Ocean acidification due to increasing atmospheric carbon dioxide. Part Two.

The RSC discussion paper explains the division of ocean waters between an upper zone, where calcium carbonate formation is possible, and a colder lower zone, where it is not possible. The fact that mass transport between these zones is very slow is stressed. The paper does not actually give a pH profile of the ocean, but here is one:

(The little dark dots are the data from today; the big circles are attempts to figure out the situation at various times in the past, which is what the paper I sourced this from is about.)

Note that the vast majority of the volume of the ocean is cold, and relatively acidic. This deep ocean is where an enormous amount of carbon is stored. Transport of carbon dioxide out of or into this layer will not be controlled by thermodynamics (i. e., where carbon dioxide it would most dearly love to be), but by kinetics (i. e., how fast it can get there). Thus, it does not matter to this zone whether or not we are adding carbon dioxide to the atmosphere at a rate unparalleled in Earth’s history or not, because that will not control how fast it gets there. It has to run the gauntlet of the warm water- where it may or may not be converted into calcium carbonate- first.

Remember the figures in the last post on how the carbonic acid equilibria change with temperature. I am now going to make the assertion- which I should now go out and try to verify- that the deep ocean is more acidic *because* it is cold.

To qualify this as-yet-unverified assertion of mine, I should say that I have not yet found any data on the pressure dependence of the pKa values in solutions of reasonable ionic strength, which is also likely to be important.

I suggest that the temperature gradient of the ocean is probably what generates the pH profile, and because transport of carbon dioxide into or out of the ocean is slow compared to how much is already there, it is the temperature dependence of the carbonic acid equilibria which control the speciation observed. Note also that the boundary between the carbonate-forming zone and the non-carbonate forming zone, from our figures below showing what the equilibria do, is going to be dependent both on the pH of the upper layers and their temperature.

Now… if climate change means anything, it means the oceans warming up. Heating the ocean and reducing the pH will pull the carbonate/bicarbonate equilibrium in different directions. I don’t know which is likely to be more significant.

Because the historical record does not show carbon dioxide spouting out of the ocean immediately as temperature increases, but lagging about 1000 years, I am not at all worried about degassing of carbon dioxide starting some feedback loop of badness : until that cold lower ocean where most all of the carbonic acid species are sitting warms up, there is no reason for significant amounts of carbon dioxide to leave the ocean. That is, if degassing of the ocean *is* the reason for the increase in carbon dioxide lagging historical temperature changes. It might not be.

Royal Society Discussion Paper, Ocean acidification due to increasing atmospheric carbon dioxide. Part One.

My thoughts keep returning to the ‘de-alkalinisation of the oceans’. I started thinking about this the other day, first because I came across that article on coccolithophores in Science, and second because one of my students is writing a review article on the use of polymer additives to stop scale formation in desalination plants. The main scales formed in these plants are calcium sulfate at high temperatures, but at somewhat lower temperatures calcium carbonate or magnesium hydroxide.

The first thing you want to know about, if you want to stop scale forming, is what are the characteristics of the solution it is forming from. So early on in the draft appears this table:

(TDS is ‘total dissolved solids’.)

I went back and had another look at the Royal Society discussion paper that I referenced before. This is the paper referenced everywhere in the web where people are fretting about ocean de-alkalinisation. The range of pH values quoted in this table is greater than the range shown in the pretty map in the Royal Society report. In fact, the range of pH values in this table is greater than the size of the maximum change in surface water pH they predict for Figure 5.

So my first thought was, if changes in surface seawater alkalinity are likely to cause bad effects, we ought to be able to see these effects already in ‘canary in the coalmine’ water bodies- shallow, warm places like the Persian Gulf. The reefs there don’t seem to be in particularly good shape but there doesn’t seem to be any evidence that seawater alkalinisation is contributing to their woes. Anyway, this table got me thinking about the problem again.

In discussing the formation of calcium carbonate scale, my student had to talk about the dependence of the equilibrium constants K₁ and K₂ on temperature and the total ionic strength of the solution, and had referenced this paper by Millero et al., where the following figure appears:

The Millero et al. paper also summarises data from a lot of previous work and gets it all to fall on the same line- see this, for instance:

In case you don’t remember,

pK_a = –log₁₀(K_a),

and in this case, K₁ is the equilibrium constant for the reaction:

H₂CO₃ → HCO₃^– + H⁺

and K₂ is the equilibrium constant for this reaction:

HCO₃^– → CO₃^2– + H⁺

These figures are telling us that in seawater (where I^0.5 ~ 0.83), the equilibrium position of both these reactions is further over to the right hand side than if they were happening in common or garden distilled water. And they also tell us that the warmer the water, the further the equilibrium will be over to the right hand side as well.

I plotted up a graph showing how the speciation of pH should change in seawater using the values in this paper and got this figure:

The Royal Society Figure 2 is pretty much the same as mine. It shows carbonate kicking in at a slightly lower pH, but there are different K₂ values floating around in the literature and I'm not sure what value they used.

Zooming in on the pH range important for discussing what is going on in the oceans:

Getting rid of the log scale, and looking at the carbonate/bicarbonate equilibrium only:

More to follow.

C'est la vie

A while ago the prolific Anonymous asked me:

What do you think about the de-alkalinisation of the oceans. Anything ruinously doom and gloom possible there? Is adaptation of water species quick enough by your reckoning?

I have recently been thinking about this a lot, due to work I am doing on calcium carbonate formation in desalination plants, and will offer a substantial critique of this particular bugbear soon.

But in the meantime, I came across this nifty figure in Science the other day and thought I would share it with you. If someone had asked me, 'how will marine organisms respond to changes in total carbonic acid species concentration?', I like to think I would have been prescient enough to draw a figure like this one. Find a niche and fill it: such is the way of living things!

The Curious Incident of the Dog in the Night-Time

Some graduation ceremonies are very dull. Others are dead interesting, and provide enough material for numerous anecdotes. If you are Jenny, you already know two anecdotes about the graduation ceremony I went to a few weekends back. This is a third one.

The main speaker at the graduation was John Ellice-Flint, distinguished alumnus, ex-CEO of Santos, and 2020 summiteer. He talked about climate change. He did it ably enough that he never had me offside. I shall give a very rough paraphrase of his speech, as it is not the done thing to take notes, and my memory is not what it once was.

He didn’t waste any time emoting about environmental catastrophe, and stated at the outset that he was going to set to one side the whole debate about the nature and extent of global warming.

He pointed out that the large developing nations were not going to abandon fossil fuels, whatever we did: we would have to accept that fossil fuels were going to be a major part of the world energy mix for some time to come.

He gave an internet factoid about the number of wind turbines China would have to build every day in order to equal the number of coal-fired power plants it was building.

He said the only way we could hope to make an impact on carbon dioxide emissions in the short-term was to throw barrow-loads of money at scientists and engineers- the one outcome of Global Warming hysteria that I have always felt to be an unqualified good.

He said he felt confident that the new government would rise to the challenge of providing these barrow-loads of money, and that in achieving world-class expertise in these areas Australia would soon earn it back many times over.

He talked a bit more about renewables, and a bit more about carbon-capture. I forget exactly what he said. I was waiting for him to mention the ‘N’ word.

But he didn’t!

Not once.

The word ‘nuclear’ did not pass his lips.

He is obviously on top of the whole big picture of greenhouse-gas abatement. He is obviously a clever bloke. He is obviously well-connected.

And it is pretty obvious that the nuclear option is one that is going to be adopted by a lot of our neighbours in our Near North, whether or not an ice age starts tomorrow, because we are going to run out of coal eventually, no matter how clean it is. It seemed obvious to me that the arguments he made with respect to developing expertise in renewables and carbon-capture applied equally well to expertise in nuclear power. And it seems obvious to me that since we are already involved in the nuclear industry as a supplier of uranium, we have not only an economic opportunity but a moral duty to take responsibility for the whole fuel cycle: to provide processed fuel to our customers (to reduce proliferation concerns) and to take back their waste (because it was ours to begin with, because we have ideal political and geological conditions to store it, and again, to reduce proliferation concerns).

But Mr Ellice-Flint didn’t mention nuclear power at all.

I am sure it didn’t just slip his mind.

I am sure he had some perfectly good reasons not to mention it.

But unfortunately, by not mentioning it, he couldn’t help but come across as someone pushing a narrow carbon-capture agenda, rather than an honest broker surveying the challenges of our energy future.

Good on him!

Dr Karl has issued a correction. Let's hope it gets as much media coverage as the original statement!

My run of luck ends

I was 4/4 for letters to major newspapers over the last couple of years. (Finding these is left as a Googling exercise for the reader). This time I have had a go at Dr Karl, and my letter has passed into limbo.

In this article in the Sydney Morning Herald on Friday, Dr Karl is quoted as claiming that Sydney produces a cubic kilometer of carbon dioxide every day, and that this makes carbon capture technologies ‘impossible’. Ignoring the dictum that the first person to mention the Nazis in an argument loses, he cites ‘clean coal’ as an example of Goebbels’ ‘big lie’.

Back in May we were told that Australians produce ‘more than five’ tonnes of carbon per capita per annum. That is, more than 18 tonnes of carbon dioxide per capita per annum.

This other site indicates that total Australian greenhouse gas emissions are of the order of 600 million tonnes of carbon dioxide per annum.

Thus, we can guess at 20-30 tonnes of carbon dioxide per capita per annum in Australia.

This gives 80-120 million tonnes of carbon dioxide per annum in Sydney.

This is 1.8-2.7 trillion moles of carbon dioxide.

Which is 40-60 trillion (10¹²) litres of carbon dioxide at atmospheric pressure.

Which is admittedly a lot.

There are a trillion litres in a cubic kilometre.

So, we have 40-60 cubic kilometres of uncompressed carbon dioxide per annum. That is more like one a week, not one a day.

Week, day, whatever. Near enough is good enough, as my uncle who builds space probes for NASA says.

The article claims that Sydney would produce a cubic kilometre of ‘compressed’ carbon dioxide per day. I don’t think Dr Karl would have said this, because it sounds too silly.

One mole of carbon dioxide at atmospheric pressure will occupy 22.4 litres. By pV= nRT, if we put it under a pressure of 100 atmospheres, it will occupy near enough to 1% of that. I don’t know what sort of pressure is appropriate for the zeroth-order ‘pumping it into empty oil and gas reservoirs’ sort of carbon capture technology. But I do know that the grail of this sort of thing is converting carbon dioxide into a solid.

One mole of carbon dioxide converted into, say, calcium carbonate, will occupy 37 cubic centimetres.

So, rather than ‘one cubic kilometre per day’ we have 0.10-0.15 cubic kilometres per day, which could be theoretically converted into 0.0002-0.0003 cubic kilometres of calcium carbonate per day. That would be about 20 times as much as the solid waste currently produced by Sydney per day. So it is still a lot. But, for the love of God, calling it a ‘big lie’ is a bit rich.

Here is how I ended my letter:

‘The fact that many different people are working on many different strategies to solve a problem should be a source of optimism and joy. That a group called the Climate Change Coalition would malign the motives of researchers pursuing carbon sequestration technologies is depressing, to say the least.’

Twitch, twitch, twitch, twitch...

When will the world listen to reason?
I get the feeling it'll be a long time.
When will the truth come into season?
I get the feeling it'll be a long time.

- The Offspring

I can't take much more of this kind of thing, I really can't. I will burst a blood vessel somewhere. This unwarranted hyperbole about climate change is going to harm the reputation of science for generations. I used to think that the collective insanity of the early 20th century was caused by mass heavy metal poisoning of urban populations and we would see saner arguments and saner policies as we moved into the 21st century. But it appears I was sadly mistaken.

If we are worried about people in the poorest regions of the Earth suffering 'malnutrition, disease, and increased untimely death rates because of heat waves, floods, storms, fires and droughts', then the logical thing to do is to bring them to a standard of living so that they will suffer as little as we in the developed world do from heat waves, floods, storms, etc.

If we are worried about the alkalinisation of the oceans, we should take a deep breath and acquaint ourselves with how flimsy the evidence for this particular doomsday scenario is.

If we are worried about coastlines disappearing, we should get rid of those dams upstream and regenerate those coastal swamps we have cleared. And we should move people away from that dangerous big blue thing which is always going to twitch and kill people, no matter what the climate does.

If parts of the planet become too hot or too cold for traditional crops, then we should switch to different crops, shouldn't we? We do this kind of thing all the time.

I can't imagine any possible scenario where Bangladesh would run out of drinking water. Very dry poor countries with high population densities survive by economising on all the other things we do with water besides drink it. Very dry rich countries don't care, because if they want more water, they just build more desalination plants.

If we are worried about extinctions, we should address the primary cause of biodiversity loss- the dangerous fragmentation of habitats. We can move people out of marginal regions to amalgamate little reserves into big reserves. The little reserve is always vulnerable. If global climate change means your preferred habitat shifts a hundred metres uphill, in a large enough reserve you move a hundred metres uphill. Conversely, if a minor local event means your preferred habitat shifts a hundred metres uphill, in a reserve that is too small you're not going to be able to move.

Coincidentally, I just came back from holidaying on the seaside at a house with very little in the way of reading matter. There were three copies of the Readers' Digest there, the oldest from August 1974. This magazine had an article about the alarming drop in global temperatures of 0.5 C since 1940 and forecasts of the dire effects to come...

Delta T

I thought I should see if I could justify my Panglossian comment on Klaus Rohde’s blog that the Ganges Delta should be able to keep pace with sea level rise.

The historical vertical deposition rates quoted in this interesting paper of 5-8 mm/year seem adequate to keep pace to all but the most extreme rates of global warming-related sea level rise. This deposition rate should also increase with any increasing incursion of saline waters into the delta, since the stability of colloidal clay particles to aggregation is reduced markedly with increasing ionic strength of the solution.

However, I had not realised that the amount of sediment reaching the Ganges Delta has already been severely reduced by the construction of dams in India, and the effects of this on the western Ganges delta were already obvious by the time the paper was written at the end of the 1980s. Hopefully India will be moved to correct this problem out of self interest, as it puts many millions of its own citizens at risk.

It also appears that intensive human use of the most marginal coastal lands- where more than a million people died the day I was born, and where nobody ought to be living- contributes significant horizontal erosion, even if overall vertical deposition rates can keep up the level of the delta.

The Prolific Anonymous Writes:

What do you think about the de-alkalanisation of the oceans. Anything ruinously doom and gloom possible there? Is adaptation of water species quick enough by your reckoning?

It seems to me that the figure in this Wikipedia article on ocean acidification, the only evidence presented there for ocean acidification as a fact, cannot possibly be based on data. In fact, the citation is a computer simulation based on carbon dioxide transport across the air/water interface.

The vast majority of these simulations are based on incorrect physics. When I was in Sydney last year I went to a talk by a physical chemist from New Zealand who talked about how mass and heat transport are coupled: you can’t calculate the flux of carbon dioxide from water to atmosphere and vice versa just by looking at the concentrations, you need to know the relative temperatures too. I worked out his equations in Excel, and a gas will move against a pressure gradient if it is moving with a temperature gradient: i.e., if the air is hotter than the water, the concentration of carbon dioxide in the water will be higher than in the air.

This physical chemist wrote two papers on this in 1991-1992 in the climate scientists’ journal of record, Geophysical Research Letters (Phillips, Leon F.. Carbon dioxide transport at the air-sea interface: Effect of coupling of heat and matter fluxes. Geophysical Research Letters (1991), 18(7), 1221-4.; Phillips, L. F.. Carbon dioxide transport at the air-sea interface: numerical calculations for a surface renewal model with coupled fluxes. Geophysical Research Letters (1992), 19(16), 1667-70.) The papers have each been cited exactly four (4!) times. I found a paper from 2003 by a collection of climate scientist chaps from Princeton and other places, who estimated carbon uptake in various places and come to the conclusion: ‘there is more carbon dioxide uptake at low latitudes, and less at high latitudes, than the models predict.’ Well, this is because the physics in those models is wrong.

This coupling of heat and matter transport also means that there will be strong diurnal and seasonal variations in carbon dioxide transport across the air/sea interface, and local concentration of carbon dioxide very much higher than those in equilibrium with the atmospheric concentration as a whole (see some of the data in here): thus organisms in the surface water layer are regularly exposed to a pH range as great as that postulated for the 'gloom and doom' prognostications.

The Royal Society summary paper on ocean acidification does not produce any convincing evidence for an overall increase in ocean pH over the period of industrial civilisation. The 0.1 increase they cite is based on a combination of proxy data (deposits of other species correlated to pH)and simulations. I am inclined to take this value with a grain of salt (NaHCO₃) and recommend that it not be used to influence policy!

I want a shoehorn, the kind with teeth

The blogosphere is full of posts by reasonably intelligent people pooh-poohing anthropogenic global warming (AGW). They cite anecdotal evidence for local cooling and sea level stasis, every bit as relevant as the anecdotal evidence for local warming and sea level rise trotted out by the other side. They look askance at the admittedly scattered plot of temperature rise vs. time (Figure 1). The messianic fervour with which the AGW propagandists push totalitarian 'solutions' to the problem pushes them to deny that AGW exists, in the same way as William Jennings Bryan was pushed into denying evolution by the way it was abused to justify Prussian militarism and robber-baron capitalism.



Figure 1: HadCRUT3 Global Temperature Data Set

Why are scientists convinced, in the main, that the AGW hypothesis is correct? It is not because of some spotty y = mx + b fit to a curve of surface temperature vs. atmospheric [CO₂](Figure 2). It is because there is a very clear mechanism by which increasing atmospheric carbon dioxide concentration should increase surface temperatures, as sure as eggs are eggs. This mechanism is dependent on fundamental physical laws that are as incontrovertible as anything can be in this crazy mixed up world of ours.



Figure 2: y = mx + b ono

In many ways AGW is the converse of continental drift. For hundreds of years, anyone with eyes could see, and say: 'Hey! This bulge in Brazil fits perfectly into the Bight of Benin!' But for hundreds of years, scientists quite properly pooh-poohed the idea of continents moving around. There was no plausible mechanism for this to happen. As soon as evidence for a mechanism arrived, so did continental drift as a reputable theory. With AGW, the lump in South America might not look very much like the dint in Africa, but the mechanism is so good that any claim that it isn't happening is bound to look like clutching as straws.

Here is the mechanism:

Energy cannot be created or destroyed. Therefore, the energy in the sunlight incident on the Earth has to be balanced by the energy in the light re-radiated by the Earth, or the temperature of the Earth will increase.

The sun sends all kinds of electromagnetic radiation out in all directions, some of which impacts the Earth, as shown in Figure 3.



Figure 3: Radiation Incident on the Earth

The difference between the upper dotted line (sunlight at the top of the atmosphere) and the lower solid line (sunlight at the bottom of the atmosphere) is the first lot of energy we need to worry about. Part of it looks like it is scattered back into space (the general fact that the solid line is lower than the dotted line) and part of it goes into increasing the kinetic energy of various molecules floating around in the air (those are all the little dimples in the solid line). These molecules (mostly water) can then knock into other molecules and increase the general kinetic energy- that is, the temperature- of the air. The more scatterers there are in the air- dust, soot, water droplets, etc.- the more energy will be scattered away, and the more water vapour (mostly) there is, the more the atmosphere will be heated directly. But on average, the solid line should not change much over time.

Now, what happens to the solid line when it reaches the earth’s surface? Either it will be reflected, and zip back off into space, or it will be adsorbed. This will be very variable indeed, and will depend on where the clouds are (they count as surface), and where the snow is, etc. Nobody is at all sure how this balance between reflection and adsorption will respond to an increase in global temperature, but a reasonable guess might be that it is likely to stay about the same.

The adsorbed energy heats the Earth’s surface. But because the whole thing has to balance to keep the Earth’s temperature the same, it has to go somewhere: and where it goes is the energy radiated by a black body heated to a not-terribly-high temperature, as shown in Figure 4.



Figure 4: Heat radiated by Earth cf. Black Body curve

The heavy green line is the theoretical curve for a black body at 255 K, and the narrower green line is observational data from an area of the Pacific ocean at about 290 K. Now you can see the bending signal of carbon dioxide! This is the big dip in the middle of the Pacific ocean curve. This dip is the rational basis for being fretty about carbon dioxide. If the dip caused by carbon dioxide gets bigger, the total area of the curve has to increase to balance the average energy coming in with the energy being radiated out. Let’s say the dip increases to where it takes up an extra 10% of the total area under the curve: the surface temperature then has to increase by a factor of approximately the fourth root of 1.1, an increase of about 6 K. 10% is of course a ruinously gloom and doom eyeballing estimate by me that probably requires a quintupling of carbon dioxide concentration, so people are worried about an increase rather less than that.

Those who are concerned about the big government, anti-Third-World-economic-development prescriptions for slowing global warming should abandon the indefensible trenches and fall back to the more defensible ones. Nobody has demonstrated conclusively that a warmer Earth will be a bad thing. A warmer Earth ought to be better for biodiversity. If some regions become unviable for human settlement, they will be regions that were marginal and dangerous for human settlement anyway. Nobody ought to live on a table-flat coast where five metre storm surges are possible, or in a fragile semi-arid region where every decade brings a drought that kills all your stock. Evidence to date is that global warming is much stronger in high latitudes, where it will improve human health, reduce energy consumption, and be an enabler of economic development. Adapting to global warming is a challenge and an opportunity. Stopping global warming is an impossible dream.

[Memo to self: remember to add citations for the images...]