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Fun with correlations!

Filed under: — gavin @ 9 May 2007 - (Türkçe)

We are forever being bombarded with apparently incredible correlations of various solar indices and climate. A number of them came up in the excoriable TGGWS mockumentary last month where they were mysteriously ‘improved’ in a number of underhand ways. But even without those improvements (which variously involved changing the axes, drawing in non-existent data, taking out data that would contradict the point etc.), the as-published correlations were superficially quite impressive. Why then are we not impressed?

To give you an idea, I’m going to go through the motions of constructing a new theory of political change using techniques that have been pioneered by a small subset of solar-climate researchers (references will of course be given). And to make it even more relevant, I’m going to take as my starting point research that Richard Lindzen has highlighted on his office door for many years:



That’s right. Forget the economy or the war(s), the fortunes of the Republican party in the US Senate are instead tied closely to the sunspot cycle.

“Oh yes”, the sceptics might say “but that’s just a couple of cycles and doesn’t use up-to-date numbers. What happens after 1986?”

Well, that is a little problematic, however, the good early correlation is obviously still important (r=0.52! 1960-1986) and so we should be able to refer to it over and over again without noting that it breaks down subsequently (cf. Svensmark, 2007 referring to Marsh and Svensmark (2000)). But more importantly, it just demonstrates that the theory needs a little adjustment.

Let’s look at the second half of the record. Well, there’s another strong correlation for that period as well (r=-0.63, 1988-2006). Only this time the correlation is inverted, but that shouldn’t be surprising to anyone – solar-senator effects are complicated!

If we now put it all together, we can see that there is a reasonable match over the whole period…. well, except that break in the period 1984 and 1988 and, unfortunately, last year’s elections didn’t fit the pattern either. But 1984-1988 was Ronald Reagan’s second term and clearly no theory of Republican senators can ignore that. We therefore propose that the ‘Ronald Reagan second term phase shift’ combined with the change of sign of the Hale solar magnetic cycle in 1986, obviously changed the dynamics. This kind of phase shift is frequently seen in solar studies (cf. Landscheidt and many others), where it is rarely taken as a sign that two time series with decadal spectral power are in fact completely independent. Finally, it is permissible to leave off the more recent data points (cf. TGGWS) for “graphical convenience”. So after just a little work, we have managed to rescue the original theory to match a much longer amount of data:



Some readers may scoff and suggest that in the absence of any mechanism, these powerful correlations are numerological artifacts arrived at using post hoc fallacious reasoning that have no predictive capability. That might appear to be a valid argument. However the ultimate test will of course be experimental. On the basis of these intriguing results, we propose exposing Republican senators to varying levels of cosmic rays in a basement and monitoring their electability. Any refusal by the funding agencies or ethical review panels to support this would simply be confirmation that the political science establishment are scared of what this research would imply for their so-called “consensus”.

Convincing, eh?

The data for sunspots and senators can, I’m sure, be manipulated even more effectively than I’ve done here. I’ve made no use of various lags or filters (which can be altered as you go along cf. Friis-Christensen and Lassen (1991)), or of partial detrending (cf. Marsh and Svensmark (2003)), or of splicing of unconnected data sets (cf. Svensmark and Friis-Christensen 1997, Nir Shaviv). More ideas could be taken from “New evidence for the Theory of the Stork” (Höfer et al, 2004)”. A special RealClimate commendation for anyone who can do better!

356 Responses to “Fun with correlations!”

  1. 101
    DocMartyn says:

    #74 Re #69 Doc Martyn,
    “I’ll do a crude calculation to give you my prediction:
    Assume the area of the 30m tank is 1 m2. First the energy added:
    8w/m2 in one year is 8 J/sec *3600sec/hr+24hr/day*365 days/year = 252 MJ
    Now the water’s response. The sepcific heat of water is about 4.2 J/g.C, which is 4.2 MJ/tonne.C. 30 metres of water with cross section 1 m2 is 30 tonnes.
    Assuming the water is well mixed and the heat distributes evenly it will take 30*4.2=126 MJ to raise the water by 1 degC
    So with 252 MJ we have a temperature rise of 252/126=2.0 deg C.
    Sounds like a good high school experiment. You could measure it with a lab thermometer. Certainly well above the noise assuming you can properly isolate the test and control tanks.

    Bruce”

    I see, so you expect that
    “Assuming the water is well mixed and the heat distributes evenly”

    although it doesn’t in any standing body of water on the planet.
    Moreover, I can’t help but notice that you have not considered the difference in evaporation rate of the two systems. Nor if there is salt present in water, the effect that thermal expansion of water will have on the salts activity. If there is thermal expansion, what effect will it have on the pressure/depth and temperature/depth profiles.

    As I stated, this is a very simple system, however, I very much doubt if any climate scientists would be interested in doing any actual, physical, expirements.

  2. 102
    Lynn Vincentnathan says:

    RE # 78 & “Gavin, are you 100% certain that CO2-emissions from humans are the reason for Global Warming? I have trouble understanding your views since you report and write about all things so completely unbiased and devoid of a particular agenda. I need to see the black & white of this, since all political decisions regarding GW are very particular and decisive, and affects so many people, and more.. Right?”

    Hi Marian,

    Actually the question non-scientists should be asking is, are you 100% sure GHGs do NOT cause GW….and when that is found to be true, we could go back to emitting them willy nilly. However, we may not want to, since inefficiency & profligacy are expensive and economically harmful.

    Even the typical scientific standard requiring 95% confidence for scientists to make claims, e.g., that GHGs are causing GW, is way too high a standard for laypersons, who (you’d think) would want to avoid harm. Scientists try to avoid the false positive (avoid making claims when they are untrue), in order to protect their reputations, but we people should be trying to avoid the false negative — avoid failing to mitigate GW when indeed it is happening. You wouldn’t want a doctor to tell you he/she is only 94% confident the lump is cancerous, so he/she won’t operate.

    Think about it a while. Do we want to risk life on earth, bec we want 100% certainty? We did get 95% certainty on GW back in 1995. By the time we get 99% certainty — maybe in a few decades — it will be too late to reverse. By the time we get 100% certainty, say in a thousand years, no one will be around to document that the scientists back in 1995 were correct afterall.

  3. 103
    Daniel C. Goodwin says:

    Intellectual Contortionist: One skilled in the art of bending one’s own mind to an astonishing extent, but in a useless manner.

  4. 104
    Timothy Chase says:

    DocMartyn (#69) wrote:

    Well there seems to be an easy test, take a pair thermally isolated tank of salt water, some 30 meters deep and irradiate the surafce, open to the atmosphere with additional IR source masked by a CO2 shroud. Measure the temperature of each tank at half meter depths and monitor any temperature difference. You might also wish to monitor the depth of the tank.

    This model is a very good test for the impact of elevated levels of CO2 on the ocean temperature.

    If the surface of one of the tanks is blasted with an additional 8w/m2 of IR radation, what will be the steady state temperature difference in the two tanks after a year?

    My estimate is as close to zero as the noise allows, although the debth will have changed.

    Since the experiment that you propose would be so easy to perform and would clearly be of great significance to us all, I wish you the best with it. However, in addition to isolating your tank from the rest of the climate, you will need a column of air approximately sixty miles high directly above it that is also suitably isolated from the rest of the climate – likewise to avoid the contamination of your results. Without that column, you won’t be measuring the feedback between the radiation absorbed by the water, the infrared radiation absorbed then re-emitted by the carbon dioxide, the water vapor coming off of the water, the infrared radiation which is absorbed and re-emitted by that vapor – and the rising temperatures of both the water and atmosphere which result from this absorbtion and re-emission of radiation and evaporation. But you should also include atmospheric circulation, otherwise whatever additional greenhouse effects you might observe could be exaggerated.

    I suppose you will need a very large tank.

    However, once you have this set-up, assuming you demonstrate how foolish the vast majority of climatologists and the long list of scientific organizations are to have subscribed to the view that carbon emissions are driving climate change, perhaps you will be charitable enough to expend some effort in determining which principles of physics become suspended in climate systems.

  5. 105
    B Buckner says:

    Thanks for the update Eli.

  6. 106
    Danniel Soares says:

    So astrology is right after all, or is it a form of telekinesis?

  7. 107
    Chuck Booth says:

    Re # 95 Timothy Chase,
    Your point is certainly well taken, but note that I said (# 88): “…very little NEW scientific knowledge comes with absolute certainty.”

  8. 108
    DocMartyn says:

    “Since the experiment that you propose would be so easy to perform and would clearly be of great significance to us all, I wish you the best with it.”
    I thank you.
    “However, in addition to isolating your tank from the rest of the climate, you will need a column of air approximately sixty miles high directly above it that is also suitably isolated from the rest of the climate – likewise to avoid the contamination of your results. Without that column, you won’t be measuring the feedback between the radiation absorbed by the water, the infrared radiation absorbed then re-emitted by the carbon dioxide, the water vapor coming off of the water, the infrared radiation which is absorbed and re-emitted by that vapor – and the rising temperatures of both the water and atmosphere which result from this absorbtion and re-emission of radiation and evaporation.”

    Typically, when one designs an experiment on only varies one parameter, this case we would only examine the effect of heat emission spectra of gaseous CO2 on water temperature on a standing body of water. We would allow free gaseous exchange and of course allow the daily and seasonal variations in atmospheric temperature, vapor content and CO2 to remain the same.

    “But you should also include atmospheric circulation, otherwise whatever additional greenhouse effects you might observe could be exaggerated. I suppose you will need a very large tank.”

    I was thinking of a pair of concrete tubes, one being a control, each made from one large and smaller diameter tube, with lightweight insulation in between. They could be poped down a pair of disused mineshafts.

    “However, once you have this set-up, assuming you demonstrate how foolish the vast majority of climatologists and the long list of scientific organizations are to have subscribed to the view that carbon emissions are driving climate change, perhaps you will be charitable enough to expend some effort in determining which principles of physics become suspended in climate systems.”

    Not at all, there are very many interesting questions that can be investigated to increase our understanding of energy transduction in aqueous systems and the mechanism of heat transfer between water and air.
    For instance, I take it that you are familiar with the concept that CO2, alone, and when in the presence of water, radiates heat, in the form of IR, from the atmosphere to the ground/water surface of our planet. It is postulated that increasing CO2 levels causes a positive feedback mechanism, so that as the planet heats up, the planet heats up even more, and so on.
    Now there are some very large bodies of standing water on our planet that contain both water and CO2.
    There seems to be no reason why the mechanism postulated for CO2 induced heating of the atmosphere/ground interface to be so much different from the ocean/seabed interface.
    Water at 2000 m has a temperature of 301K, and so will emit across a nice board range of the IR spectrum with a peak intensity at 10 microns. Much of this IR with be reabsorbed by H2O/CO2 and then reemitted, upward and downwards. IR will then bounce around the oceans until hit hits the seabed, heating it up, or the very surface and manages to evade all the H2O/CO2 in the atmosphere and make it into space. Now as the surface water is hotter than the depths, more IR must makes it way down to the depth, than makes it up to the surface, as; 1) the surface water is hotter ands so emits more power than the depths and 2) the black body spectrum of the surface water is further away from the H2O/CO2 absorption peaks. If we accept the proposed mechanism (GHG) for ground heating by atmospheric H2O/CO2, we should also accept it for the heating of the seabed by oceanic H2O/CO2.

    So I should like to know:-
    1) How does the ocean transfer heat to the atmosphere?
    2) How is the large temperature differential, with water depth, maintained?
    3) By what mechanism is heat transferred from the ocean depths to the surface and vise versa?
    4) How much will IR heat the oceans?
    5) Does CO2 reradiated IR energy differ in its ability to change water temperature, compared with other energy source?
    6) Why isn’t there no CO2/water driven run-away heating of the oceans whereby IR trapped by H2O/CO2 is transferred to the seabed?

  9. 109
    Jim Eager says:

    Re #78: “Gavin, are you 100% certain that CO2-emissions from humans are the reason for Global Warming?”

    Why do so many people expect 100% certainty that human activity is a cause of gw/cc when virtually no other assessment that humans make is based on 100% certainty

  10. 110
    Ike Solem says:

    When it comes to assessing climate change and global warming, the person to ask is a climate scientist. No scientist is going to claim they are absolutely certain about the future, for many reasons – for example, a massive asteroid strike or the biggest volcanic eruption in a million years are not impossible events. However, paleoclimate studies, climate models, and direct observations all support the concept of anthropogenic global warming caused by CO2, CH4, N2O, and other IR-absorbing gas emissions, which are primarily due to the use of fossil fuels.

    When it comes to assessing risk and responding to risk, the people you want to ask are the insurance industry experts. They are quite worried about the long-term survival of their industry: see here, and here, and here.

    A few quotes:

    The U.S. government, insurer of last resort, faces a potential payout of at least $919 billion under a worst-case scenario of flood and crop losses due to global warming, congressional investigators say.

    “Climate change will significantly affect the health of humans and ecosystems and these impacts will have economic consequences,” concludes a new study cosponsored by Swiss Re, a global re-insurance company.

    This doesn’t mean that the insurance industry knows how to replace fossil fuels with clean energy sources; for that you want to talk to experts in renewable energy technology.

    Climate scientists will tell you that anthropogenic global warming is real. Insurance executives will tell you that it presents significant economic risks. Governments will tell you that these risks are so severe that they could lead to global warfare (i.e. the UN Security Council report), and renewable energy experts will tell you that the technology exists to meet global energy needs, but only if steps are taken to reduce global energy demand – i.e. conservation and energy efficient technology are necessary components of any strategy.

    However, fossil fuel interests will tell you that reducing energy demand and switching to renewables will wipe out their industry. All of which begs the question: why can’t the fossil fuel industry switch immediately to renewables? The only objection to that seems to be that it would drastically reduce their short-term profit margins. Hmmm… is that a valid objection, considering the magnitude of the risk?

  11. 111
    Timothy Chase says:

    Chuck Booth (#107) wrote:

    Re # 95 Timothy Chase,
    Your point is certainly well taken, but note that I said (# 88): “…very little NEW scientific knowledge comes with absolute certainty.”

    I had agreed, but then took it a step further: “Empirical science never reaches absolute certainty, but it can approximate it.” (#95)

    However, large bodies of evidence, multiple independent lines of investigation leading to the same conclusions, and connections with what we already know can all add up into something almost as solid as the floor you last walked across without a second thought.

    Of course many of the conclusions of climatology don’t have that degree of justification – but then again it would be dishonest to argue as if climatologists were claiming that sort of certainty, wouldn’t it?

  12. 112
    Timothy Chase says:

    DocMartyn (#108) wrote:

    So I should like to know:-
    1) How does the ocean transfer heat to the atmosphere?

    The two mechanisms which would predominate are evaporation carrying away the heat by means of evaporation (this is afterall what drives hurricanes) and radiation.

    2) How is the large temperature differential, with water depth, maintained?

    Temperature differential? Undoubtedly this would depend. However, last I read, we know that the temperature is measurably increasing as far down as 1500 meters. This is one reason why hurricanes are becoming more powerful.

    3) By what mechanism is heat transferred from the ocean depths to the surface and vise versa?

    Principally by means of convection, but ocean depths tend to be cooler.

    4) How much will IR heat the oceans?

    Rather than asking me or engaging in armchair climatology, you might try asking climatologist. We have several here.

    5) Does CO2 reradiated IR energy differ in its ability to change water temperature, compared with other energy source?

    Why should it?

    6) Why isn�t there no CO2/water driven run-away heating of the oceans whereby IR trapped by H2O/CO2 is transferred to the seabed?

    At this point I would strongly recommend going to a climatologist: it is beginning to look like you are out of your depth, oceanic or otherwise.

    Gavin devoted an entire essay to explaining why positive feedback does not as a rule result in an endless runaway effect:

    5 Jul 2006
    Runaway tipping points of no return
    http://www.realclimate.org/index.php/archives/2006/07/runaway-tipping-points-of-no-return/

    The greenhouse effect itself depends upon positive feedback, but it does not generally result in run-away process.

    The following post of mine explains why – in the context of Gavin’s “simple model” (with an increased greenhouse effect due to carbon dioxide, the temperatures of the surface and the atmosphere rise until the thermal energy leaving the system in the form of infrared radiation equals the amount of thermal energy entering the system through the absorbtion of light from the sun by the surface), and it includes a link to a spreadsheet I created which will give you the chance to play with the numbers (if you export it to Excel)…

    A Spreadsheet for the Simple Model
    http://www.realclimate.org/index.php?p=411#comment-32400

    There is a little more in the post that immediately follows it.

  13. 113
    FurryCatHerder says:

    Re #108:

    Now as the surface water is hotter than the depths, more IR must makes it way down to the depth, than makes it up to the surface, as; 1) the surface water is hotter ands so emits more power than the depths and 2) the black body spectrum of the surface water is further away from the H2O/CO2 absorption peaks. If we accept the proposed mechanism (GHG) for ground heating by atmospheric H2O/CO2, we should also accept it for the heating of the seabed by oceanic H2O/CO2.

    Water absorbs red wavelengths like nobody’s business. Assuming that IR goes much of anywhere in water is incorrect.

    I forget how deep I was when I shot this photo, but I’m pretty sure it wasn’t more than 60′. You’ll notice that it’s devoid of reds.

    Photo Sharing and Video Hosting at Photobucket

  14. 114
    Timothy Chase says:

    Jim Eager (#109) wrote:

    Re #78: “Gavin, are you 100% certain that CO2-emissions from humans are the reason for Global Warming?”

    Why do so many people expect 100% certainty that human activity is a cause of gw/cc when virtually no other assessment that humans make is based on 100% certainty?

    Perhaps because they are looking only at the costs of trying to do something about climate change, not the costs of climate change itself. As long as they can entertain some doubt somehow, they don’t have to regard the costs of climate change as real – and all they see are the costs of trying to do something about it.

    If this makes as much sense to you as the sound of one hand clapping, I would suggest that the sense of paradox you are experiencing says at least as much about you as it says about them.

  15. 115
    Charlie (Colorado) says:

    Now, just imagine how fascinating it would be if there were some plausible physical explanation for, say, the correlation between solar activity and global average temperature.

  16. 116
    Timothy Chase says:

    FurryCatHerder (#113) wrote:

    Water absorbs red wavelengths like nobody’s business. Assuming that IR goes much of anywhere in water is incorrect.

    I forget how deep I was when I shot this photo, but I’m pretty sure it wasn’t more than 60′. You’ll notice that it’s devoid of reds.

    That’s right – although at the moment that I responded, I wasn’t entirely sure.

    The dots connect…

    I have seen the photos.

    Likewise, I remember that deepwater fish have their perception of color shifted towards the blue end, and the deeper down you go the more shifted it becomes. An evolutionary adaptation, much like how ice fish have amino acids added to a protein through hypermutation in a triple repeat – so that it acts as an antifreeze. In the more extreme cases (species which are further along the path), lower temperatures raise the amount of oxygen that the blood can carry, but red blood cells thicken the blood, so as an evolutionary adaptation, they lose their red blood cells. They are transparent, not a hint of red, hence the name.

    The bit about ice fish might not seem that important, but the same principle applies to the ocean: as the temperature rises, the capacity for carrying oxygen and carbon dioxide is diminished. The ocean is at first a sink for carbon dioxide, but then it becomes an emitter. Raise the temperatures in the artic and the amount of oxygen it picks up before being cycled through the ocean is lowered. Fish eventually suffer from anoxia. But we may lose the ice fish first – according to the use-it-or-lose-it rule. The genes which coded for hemoglobin might be able to recover, depending upon how much they have mutated since they were last used, but there won’t be anywhere near the time that would be necessary.

  17. 117
    Ron R. says:

    Off Topic.

    We are surrounded by BUFFOONS!!!

    A couple of stories you gotta read together. Warning, It’ll make your blood boil.

    http://seattletimes.nwsource.com/ABPub/zoom/html/2003694662.html

    http://www.kfdm.com/news/bees_20379___article.html/bee_apartment.html

  18. 118
    Daniel C. Goodwin says:

    Re 110: Ike Solem, thanks for your incisive summary, pretty much covering all the bases in very few words: “Paleoclimate studies, climate models, and direct observations all support the concept of anthropogenic global warming caused by CO2, CH4, N2O, and other IR-absorbing gas emissions, which are primarily due to the use of fossil fuels.”

    Regarding insurance concerns: the beginning of our fire season in the United States is looking worse than ominous, as the Missouri river rises, in the wake of a terrifying spate of tornados. How much punishment is necessary before people are willing to inconvenience themselves for the sake of moderating global warming? How much more brutally simple does it need to get?

    Sorry, one of my interests is the impossibility of getting through to anyone substantively. It’s a psychological or sociological question which got tangled up in this, because we are the source of the problem. If a perfectly obvious observation (such as Solem’s) fell in the woods, and no-one was there to hear it, did it make a sound?

  19. 119
    FurryCatHerder says:

    Re #113:

    Okay, the preview showed the photo, but it was lost …

    Here’s the pic — Red absorption in water

  20. 120
    Marion Delgado says:

    In fairness (and I’ve only glanced at a couple of comments so far), we should take a stab at debunking the meaning of this correlation without circular recourse to the badness of assuming correlation is causation.

    So let’s have at it. A comparison of how robust it is to solar theories would be instructive.

  21. 121
    Marion Delgado says:

    I note immediately it’s a bit exaggerated compared to the original, and indeed, you need to attack the politician sunspot thing both to highlight the similarity to solar cycle climate change arguments AND distinguish it from the carbon dioxide temperature correlation.

    I must say though, the urban liberal island idea by tamino is SHEER GENIUS. It makes the post for me.

  22. 122
    Bruce Tabor says:

    Re: #101, 104, 108, 112 DocMartyn and Timothy Chase,

    Doc,
    You’ve prposed a physical model, which for reasons Timothy points out is not a good approximation to the ocean. I’ve done a theoretical calculation, which in its own way is not a good approximation. My main point was that this amount of power (8w/m2), although it appears small, will have measurable effect (2 degC) on 30 tonnes of water over a year.

    I think one of the main shortcomings of the 30 metre well of water is it will not adequately reproducing the mixing effect in the upper layers seen in the oceans. In fact if we didn’t have this mixing I suspect the impact of raised CO2 on climate would be greater as the heating of surface of the ocean would be restricted to shallower depths, and it is change in ocean surfacce temperatuires that drive climate change.
    Cheers,

    Bruce

  23. 123
    Bruce Tabor says:

    Re 112 Timothy,
    Thanks for the spreadsheet Timothy. I’ve read Gavin’s simple model and down loaded the spreadsheet. I am a little time-poor at the moment so I hope to get to it later.

  24. 124
    ray ladbury says:

    DocMartyn, I don’t even know where to begin. Maybe let’s start with how a scientist would approach your questions. First, he’d research them. He’d actually go out and crack some books and some journals and see what people have done before. If YOU were to do this, you would find that most of your questions have been answered.
    1) When you heat water, it’s temperature increases, but it also evaporates. The water vapor has a higher energy than liquid water (its latent heat) that it takes with it as it rises into the air. When the water vapor condenses into water droplets (clouds) it yields that heat (a lot of it) back to the atmosphere.
    2)Water absorbs light pretty efficiently. By the time you are 60-100 meters down, it’s pitch black. So you’ve got all that sunlight heating the upper 100 meters and none below. Water expands when it is heated, so the upper 100 meters for the most part is less dense and floats on top of the cold, dense water underneath.
    3)Heat is transfered from the surface to the depths by ocean currents. One consequence of all that warm water evaporating is that the water on top tends to be saltier, and this increases density. After the water flows north a bit and cools, it is heavy enough to sink down to the even colder depths. This is what drives the Gulf Stream, for instance.
    4)The oceans are heated by all the radiation they absorb, not just the IR. Basically the oceans will be heated to the point where they are in thermal equilibrium with the atmosphere and the radiation field above them. Increase the temperature or the radiation and the oceans will heat more. This is one of the things you can find out in text books and journals.
    5)I can’t quite figure out what you’re asking here. If you want to know how much of the IR radiation at the wavelength of CO2 absorption will be absorbed if said photons are incident on the ocean, the answer is all of it. Radiation is radiation. It is a fundamental principle of quantum theory that all photons of the same energy are indistinguishable. What CO2 does is increase the energy that stays in the atmosphere. That warms the whole planet–oceans and all.
    6)Why would there be such a runaway heating? Most of the oceans is insulated from what goes on at the surface by the warm layer above it that absorbs all the light.

    If you want controlled experiments, stay in the lab. The rather sizeable sum your experiment would cost would be better spent on experiments, modeling and satellite missions that would tell us something we don’t already know.

  25. 125
    ray ladbury says:

    Re: 78. Marian wondered whether Gavin is 100% certain that CO2 is behind climate change. Several have pointed out that science cannot be 100% certain about anything. Here’s another clue: Nothing is ever 100% certain. That is one of the brilliant realizations of the scientific method. If you want to know anything, give up on certainty. Science is descended from the tradition of thought in Western philosophy called rationalism, which held the (at its time) heretical notion that humans could figure things out by thinking about them. DesCartes was the most famous rationalist, and to get an idea of how seriously he took uncertainty, his dictum, “I think; therefore I am,” was an attempt to prove that he even existed. (BTW modern philosophers challenge even this proof’s certainty.) Nothing is certain. I cannot be certain that I am awake and typing and not dreaming. I cannot be certain that the Sun will rise tomorrow or even that it rose today (could be dreaming again, after all).
    You even had Bishop Berkley asserting that the world was just a dream in God’s mind and had no real existence. Saying this was all the rage in London, and sophists of the time loved taunting the rationalists saying, “You can’t refute it.” This led to the incident where Ben Johnson famously kicked a big rock and limped off, saying, “I refute it thusly.”
    The brilliance of Galileo, Francis Bacon, Newton and the other founders of the scientific method was that they gave up on certainty, and lo and behold the modern world was born. Science delivers knowledge that is as close to certainty as we can get. It is knowledge well beyond even the seeming certainty of daily life. It is just that because scientists know NOTHING is certain, they have developed a different way of using the language. Where a layman would say, “I know…” a scientist would say “I believe…” or more accurately, “We believe…” because consensus is essential to the scientific method.
    I will again recommend the excellent essay by Helen Quinn from the January Physics Today:
    http://www.physicstoday.org/vol-60/iss-1/8_1.html

    So, let’s put paid to these pernicious myths that because climate change is not 100% certain, it isn’t science, or that because science doesn’t deliver 100% certainty, it is somehow an inferior. When the world’s climate change experts nearly unanimously say that they are 90% certain that humans are causing climate change, you can take that to the bank. And when someone comes to you offering 100% certainty, keep your hand on your wallet.

  26. 126

    You are very welcome, Arvella. If I can help with anything, please don’t hesitate to e-mail me (bpl1960@aol.com). That being said, I’m not a climatologist, just a loud-mouthed would-be writer with an ancient physics degree.

  27. 127

    [[I very much doubt if any climate scientists would be interested in doing any actual, physical, expirements. ]]

    The history of general circulation models starts, among other things, with fluid on a rotating disk in a famous series of physical experiments. See Weart’s book (accessible from the right panel).

  28. 128
    Chuck Booth says:

    Re # 111 Timothy Chase: I agree

    Re # 124 Ray Ladbury: I agree with most of your comments, but feel compelled to clarify this one: “By the time you are 60-100 meters down, it’s pitch black.”

    That is certainly true in some productive lakes and coastal waters, but in the open ocean (and in the clearest freshwater lakes), light penetrates much deeper. The lowest depth at which photosynthesis exceeds respiration (= the compensation depth) is 100-200 meters in the open ocean, and well over 100 meters in some clear lakes (at least that was true a few decades ago; Tahoe, once one of the clearest, is becoming eutrophic). And measurable levels of light (though not sufficient for photosynthesis)occur another 100 or so meters down. Some data on this are reported in: The Oceans Their Physics, Chemistry, and General Biology, by Sverdrup, Johnson, and Fleming (http://content.cdlib.org/xtf/view?docId=kt167nb66r&brand=eschol); see Table 92 (http://preview.tinyurl.com/yoqa8n))

  29. 129
    Timothy Chase says:

    ray ladbury (#125) wrote:

    Science delivers knowledge that is as close to certainty as we can get. It is knowledge well beyond even the seeming certainty of daily life. It is just that because scientists know NOTHING is certain, they have developed a different way of using the language. Where a layman would say, “I know…” a scientist would say “I believe…” or more accurately, “We believe…” because consensus is essential to the scientific method.

    (Emphasis added.)

    In my view, this is not entirely accurate, but a fairly good approximation. In my view, empirical science has the right to claim not simply “I belief” but “I know.” Moreover, it should: otherwise science cannot claim “justification” or “objectivity.”

    In epistemology and the philosophy of science, we generally distinguish between “corrigible knowledge” and “incorrigible knowledge.” Corrigible knowledge is knowledge which has met a standard of justification, but which is not known with absolute certainty. Incorrigible knowledge is regarded as knowledge since its denial would be self-referentially incoherent, that is, would involve a contradiction between the denial itself and the context which must be presupposed for the act of denial to be meaningful.

    It is relatively easy to demonstrate to satisfaction of most that “corrigible knowledge” must be regarded as a form of knowledge. Most would grant, for example, that any empirical claim regarding the external world must be mediated, that is, must involve a means of perception. Likewise, they would grant that as individuals, any knowledge of the past presupposes beliefs involving a process of memory, and as such, their knowledge of the past itself is mediated.

    However, most would accept the fact that any knowledge of the external world which is mediated means that it is at least in principle capable of error. Examples of where knowledge claims may be subject to error involve perceptual illusions and instances in which we thought we remembered something accurately but were mistaken. In principle, any argument which involves one remembering something from a moment ago or which ultimately involves this form of memory depends upon this (such as when we first learn how to distinguish between awareness, memory or emotion) is therefore dependent upon knowledge which is at least in principle corrigible. (This, incidently, is the Achilles’ heal to one of Descartes’ central arguments.)

    As such, while one may be able to claim incorrigible knowledge where the denial of such knowledge would involve self-referential incoherence, one’s claims to such knowledge would themselves be dependent upon regarding corrigible knowledge (knowledge whose justification is a matter of degree) as a form of knowledge.

    Now why is this important?

    If one claims that science is not capable of knowledge but merely belief, one’s listener might get the impression that there are no standards of justification and that all claims to knowledge are nothing more than subjective, arbitrary beliefs. As such, they could claim that science is simply a form of faith and then that there is no standard by which to choose between this faith and some other faith which maintains claims which are entirely at odds with it.

    However, one’s acceptance of the conclusions of science is not merely an arbitrary act of an entirely subjective will. Scientists have the right to claim knowledge even though the justification of any claim of empirical science is justified, but never justified to the extent that it achieves absolute certainty.

    *

    In any case, later on I will probably provide a short link to a critique of Karl Popper’s principle of falsifiability. As for you wallet, I would prefer that you keep your hand on it.

    Take care…

  30. 130

    Hi Guys!

    This is a revamp of a video about GW I did a few months ago, which I think you posted on your site. I used the term anthropomorphic instead of anthropogenic. Silly and rather embarrassing. That’s corrected now, and I’ve tightened up the voice over so it’s a but shorter, coming in at about 5 mins.

    http://www.youtube.com/watch?v=4NcRPQeRp_M

    It also touches on the scientific method, and the damage that creationism has done to science in general, so although not the typical fare of your site, it may be of interest.

    If the video helps your audience, by all means use it.

    Regards,


    Brian Coughlan
    Skpe:briancoughlanworldcitizen

  31. 131
    tamino says:

    Re: #130 (Timothy Chase)

    Very interesting. I’m out of my depth when it comes to epistomology, but as a statistician it seems to me that we can apply a probabilistic approach to events which are testified to by multiple witnesses, multiple times, and eventually reach a point where the probability that all the testimony is an artifact of failed memory or tricky perception becomes so low, that it can be regarded as practically zero. Conservation of energy-momentum springs to mind. In that case, can we claim knowledge?

    Then of course there’s the questions of mathematics — the only science in which one can claim absolute proof. Do we have knowledge of pi?

    I’m confident that Homer Simpson would reply, “Mmmmmmmmm… pi”

  32. 132
    James says:

    Re #125: […a scientist would say “I believe…”]

    I agree with the argument, but not the word choice. Believe is a word I try to avoid when discussing science. The problem is that there are two inherently contradictory usages of the word “belief”. The first describes the process by which the followers of e.g. religions and political systems hold the tenets of their particular belief system. There doesn’t seem to be any empiricism involved at all: if your leader or holy book says that Artesians are responsible for all the ills of society, the believers don’t ask for evidence, they just go massace Artesians. This sort of belief is absolutely certain, even when non-believers prove that it’s wrong.

    Scientific “belief”, on the other hand, is (or in a perfect world should be) entirely empirical. That makes me “believe” that for instance things thrown into the air will fall down, and that with the right formulas I can even predict when and where. But if you claim to have an anti-gravity machine, I won’t reject it out of hand because it conflicts with my empirical scientific knowledge. I’ll ask for a demonstration, and if it works, modify my previous view of falling things to include “except when Ray’s using his anti-gravity machine”.

    The problem with climate change is that we have a lot of people who have an implicit belief of the first sort (which might be paraphrased as “the world was created for the benefit of humans, therefore this can’t possibly happen”), and that trumps any and all empirical evidence to the contrary.

  33. 133

    #129, Timothy Chase, May 12, 1133 am: “Scientists have the right to claim knowledge even though the justification of any claim of empirical science is justified, but never justified to the extent that it achieves absolute certainty.”

    Timothy, you used the phrase “absolute certainty” at least twice. For you, what does that phrase mean?

  34. 134
    David B. Benson says:

    “belief”, “knowledge”, “probability” — A subjectivist Bayesian ascribes probabilites to beliefs, the higher the more certain. If by knowledge one means holding a true belief, that is, a belief which is in fact correct, then the subjectivist Bayesian strictly speaking never does this, only ascribing a probability very, very close to one, but not yet equal to one.

    Life is too short for such games when the matter seems clear: the sun will rise once again in the morning, etc.

    There are also the objectivist Bayesians and the likelihoodists. For a starter, see the section on inductive logic in the Stanford Encylopdia of Philosophy. Some might care for warmups using the Wikipedia pages including those for Bayes factor, naive Bayes classifier and other links found on those pages.

  35. 135
    Timothy Chase says:

    I will do this in two parts. The first will be of more general interest, but the second may be so specialized that RealClimate might prefer not to post it – which is of course entirely their decision…

    Part I:

    Tamino (#131) wrote:

    Very interesting. I’m out of my depth when it comes to epistomology, but as a statistician it seems to me that we can apply a probabilistic approach to events which are testified to by multiple witnesses, multiple times, and eventually reach a point where the probability that all the testimony is an artifact of failed memory or tricky perception becomes so low, that it can be regarded as practically zero. Conservation of energy-momentum springs to mind. In that case, can we claim knowledge?

    Not a problem – I am out of my depth when it comes to anything beyond basic statistics.

    I would agree that multiple witnesses and multiple observations can increase the probability of scientific claims being true. This is in fact simply a narrower application of the principle that when a given conclusion receives justification from multiple, independent lines of investigation, its degree of justification can be far greater than that which it would receive from any given line of investigation considered in isolation from the rest. This is essential to both individual cognition and a community-based scientific enterprise. Moreover, with regard to many of the conclusions which science arrives at, it is capable of claiming justification which is arbitrarily close to that of certainty – particularly within the context of a community.

    Moreover, I would most certainly claim that empirical science is capable of not simply “belief” but “knowledge,” corrigible knowledge. In principle, it is possible that some evidence may be discovered at some later point which requires us to entirely abandon nearly any given scientific claim no matter how well justified it might be. However, if one denies “corrigible knowledge” the status of knowledge, then as a matter of principle, one undercuts any and all claims to knowledge – including what few propositions may in fact acheive incorrigibility – such that the very act of denying them must presuppose their truth and thus cannot be rationally maintained due to an incoherence implicit in the act itself.

    In any case, my essential point is this: science can properly claim not simply belief, but objectivity, justification and knowledge. Radical skepticism is not a rational alternative to empirical science. Neither is dogmatic fundamentalism. Moreover, there is a core to a minimalistic rational defense of empirical science. I don’t think that it is necessary to go into the details here – and I am not entirely sure that I would be able to finish the job to my personal satisfaction if I tried. But it is important to understand its general thrust if for no other reason than being able to respond to those who would assert that truth (including scientific truth) is a function of one’s class, race or religious belief.

    For example, both young earth creationists and proponents of intelligent design will sometimes claim that mainstream science is founded on some form of atheistic materialism, and that what they wish to regard as science necessarily presupposes a religious foundation. Likewise, the have been a large variety of movements which argue that all beliefs are ultimately a function of the ideologies of those who hold them. By holding that science isn’t capable of knowledge but only believe, one leaves science more vulnerable to such ideologically-motivated attacks.

  36. 136
    ray ladbury says:

    Tamino, There are interpretations of scientific knowledge in terms of Bayesian “degree of belief”. There are others that look only at relative probability as defined by likelihood. An interesting issue with the Bayesians is that if one’s Prior is zero at any outcome, it is impossible to get a nonzero probability even if it is realized. If the denialists assign zero probability of anthropogenic causation–they’ll never believe in it no matter what the evidence says.
    As to mathematics, the incompleteness theorem shows that even in arithmetic, 100% certainty is impossible. That is, even mathematics is at some level empirical. According to Gandhi and certain mystics, religion is empirical as well. The problem with religions: They are founded by geniuses and practiced even by idiots.

  37. 137
    Timothy Chase says:

    Part II:

    Alright. Part I was of more general interest.

    This part is much more specialized. However, it may be of interest to those that deal with issues in epistemology, the philosophy of science, or have an interest in the philosophy of science. Normally I would prefer not to go off in this direction – as it would seem to divert our attention from the proper focus of Real Climate. However, I myself will make an exception as a couple of individuals expressed some interest.

    But I think David Benson has the right idea, and after this we should probably move on…

    Tamino (#131) wrote:

    Then of course there’s the questions of mathematics — the only science in which one can claim absolute proof. Do we have knowledge of pi?

    The truths of logic and mathematics are often capable of being known with certainty. However, with regard to their truth, the central question becomes, “How are they related to reality?”

    For example, there are those who study what are called “alternate logics.” Given the existence of alternate logics, it is sometimes argued that logic is simply a matter of convention. However, when examining any alternate logic, one of the first questions should always be, “Is it internally consistent?” If it is not internally consistent, then it is incoherent and cannot be considered a rational alternative to more traditional forms of logic. But one cannot determine whether or not an alternate logic is internally consistent by appealing to the alternate logic itself, and thus one must have recourse to traditional logic if the alternate logic is to be a rational object of study.

    Likewise, mathematics can be built upon the foundation of logic. However, how does it relate to the world? Kant, for example argued that some propositions are true simply by definition (analytic a priori truths), others are empirical but dependent upon experience (synthetic a posteriori truths), independently of experience but are empirical in nature (synthetic a priori). But one of the more important arguments against this view is that there is no general criteria by which to decide whether a given truth is analytic or synthetic a posteriori. Alternatively, early in the twentieth century, logical positivists argued that all statements are either analytic a priori or synthetic a posteriori – doing away with propositions in favor of statements, and abandoning the synthetic a priori as meaningless. In their view, anything which could be known with certainty would simply be true by convention.

    However, logical positivism was abandoned – largely because any version of logical positivism was as a matter of principle self-referentially incoherent. Likewise, it has been argued that Kant is self-referentially incoherent. However, in an essay on “The Critique of Pure Reason,” I argued that the “critique” is self-referentially incoherent if and only if it is regarded as a product of what he refered to as “pure theoretical reason.” But I also argued that if it is not a product of “pure theoretical reason,” then in terms of his system, it must be regarded as a product of “pure practical reason,” in which case it is circular. In either case it is untenable. Moreover, I extended this criticism to the analytic/sythetic dichotomy itself.

    If you think about it, any concept which we might employ is meaningful if and only if it is somehow related to reality. As such, in my view, while definitions are certainly useful, there ultimately isn’t much point in trying to divide all propositions or truths into those which are simply “true by definition” and those which are regarded as true as a function of evidence. Likewise, conventions aren’t entirely conventional: there is often good reason for chosing one convention over another, and the reason is oftentimes empirical in nature. As a consequence, it would appear that what are sometimes called analytic truths are analytic, but are analytic only within a network of beliefs where the network itself must be at least in part empirical in nature, and where such analytic truths can be regarded as meaningful only as the result of their being a part of that network.

    Burgess Laughlin (#133) wrote:

    Timothy, you used the phrase “absolute certainty” at least twice. For you, what does that phrase mean?

    *

    Normally I wouldn’t even speak of absolute certainty except in order to introduce the distinction between and the necessity of corrigible and incorrigible knowledge. However, by “absolute certainty,” essentially I mean what is refered to as “Cartesian certainty.”

    *

    David B. Benson (#134) wrote:

    Life is too short for such games when the matter seems clear: the sun will rise once again in the morning, etc.

    I agree.

    Moreover, I am found of the Bayesian approach.

    Let’s get back to the science!

  38. 138
    ray ladbury says:

    James, if you read the essay by Helen Quinn, that is pretty much the argument she is making. I was not advocating the use of “I believe” over “I know”–merely giving historical perspective.
    Tim, I strongly recommend the essay.

  39. 139
    David B. Benson says:

    “scientists believe…” “scientists know…” are both likely to engender confusion, IMO. Using “scientists are 90% confident that…” or “scientists are 99.9% confident that…” is clear and correct when an appropriate statistical test has, in fact, been performed.

  40. 140
    Timothy Chase says:

    ray ladbury (#136) wrote:

    As to mathematics, the incompleteness theorem shows that even in arithmetic, 100% certainty is impossible. That is, even mathematics is at some level empirical. According to Gandhi and certain mystics, religion is empirical as well. The problem with religions: They are founded by geniuses and practiced even by idiots.

    According to the incompleteness theorem, for a mathematical system of sufficient complexity, either the system is incomplete, which means that while it is possible to prove some statements to be true, there will always be some statements which are meaningful (in the sense that they can be expressed in the language of that system) but which cannot be proven, or the system will be inconsistent. And yes, arithmetic is sufficiently complex that it must be incomplete or inconsistent. I am betting on the former myself.

    With regard to religion, you won’t get any disagreement from me there. In any case, it looks like we have similar viewpoints in a number of areas.

  41. 141
    Timothy Chase says:

    David B. Benson (#137) wrote:

    Using “scientists are 90% confident that…” or “scientists are 99.9% confident that…” is clear and correct when an appropriate statistical test has, in fact, been performed.

    I believe this is the right way to go – with the stuff that is cutting-edge – which is generally what scientists are interested in talking about. But what if someone denies that we know that mammals descended from reptiles, or reptiles from fish? The evidence is overwhelming. What if they wish to deny that carbon dioxide is a greenhouse gas? Or that at the quantum level, particles behave like waves? These aren’t simply things that I am confident about – and it would be rather bizarre to try and subject them to a statistical test insofar as they are so well established or derivable from something which is. Likewise, there wouldn’t be much sense in performing a Beyesian analysis on them.

    In my view, given the context, it is perfectly acceptable to say we know these things, and that for all intents and purposes, we are certain about them – even though they aren’t instances of incorrigible knowledge.

  42. 142
    Chuck Booth says:

    Re # 137 Using “scientists are 90% confident that…” or “scientists are 99.9% confident that…” is clear and correct when an appropriate statistical test has, in fact, been performed.

    I’m sure Tamino and others more versed in statistics than I am will correct me if I am wrong, but your statement strikes me as an inaccurate (albeit common) interpretation of statistical probability (that is, P values and confidence limits). P values and confidence limits represent the statistical probability that a specific observed event, or distribution of data values around a mean, was due to random chance, as opposed to some non-random “forcing” if you will (to borrow a term from climatology). This really has nothing to do with the confidence a given scientist has that his or her conclusion is correct (which is how I interpreted your response; I have seen similar statements on other RC threads and in the popular press). In analyzing data, scientists usually have no basis for expressing their confidence that a result is correct outside of their knowledge of how to interpret a statistical test of randomness vs. non-randomness (except their “gut” feeling that something is right, or wrong, with their data based on prior experience).

  43. 143
    David B. Benson says:

    Re #141: Timothy Chase — I agree, largely, especially with your last paragraph. Indeed, some notion of confidence (or probability that a certain hypothesis best explains the evidence) is used in rational decision theory to inform decision makers. What is usually called the background is the part we are so certain about that we simply accept the laws. Said another way, the probability is taken as one and only the most pedantic Bayesian would object.

    Re #142: Chuck Booth — I believe I used the term rather precisely, following the literature on hypothesis testing. See my previous post which offers links into the literature on selecting one hypothesis over another, often called inductive logic. In particular, the competing hypothesis can be, and often are, completely deterministic. But alas, the data collection often contains some error, often taken as random. This, of course, means that one can at best determine only the likelihood that one hypothesis is better than the other. Then there are standard methods to express what is often called the confidence.

    It is not that non-practitioners of statistical reasoning won’t be slightly misled by expressions about confidence, they will. But they will be only slightly misled as opposed to the use of the term believe, which is fraught with possibilities of the deepest misunderstandings…

  44. 144
    DocMartyn says:

    Dear ray ladbury, let me thank you for your reply and your insights into climate science.

    “Maybe let’s start with how a scientist would approach your questions. First, he’d research them. He’d actually go out and crack some books and some journals and see what people have done before. If YOU were to do this, you would find that most of your questions have been answered.”
    I thank you for your advice.

    “1) When you heat water, it’s temperature increases, but it also evaporates. The water vapor has a higher energy than liquid water (its latent heat) that it takes with it as it rises into the air. When the water vapor condenses into water droplets (clouds) it yields that heat (a lot of it) back to the atmosphere.”

    Indeed, this is PARTLY true, however what is the relationship between the source of the energy input and its effects; i.e. if we put exactly the same amount of energy into the system, but using photons of different wavelengths, do we get the same outcome? No.

    What I would like to know is the relationship between the frequency of light poured into a body of water and the change in the evaporation rate and change in the temperature gradient of a body of water. Now different frequencies of light will give different results, even if the energy input into the system is the same.
    For instance, pure water absorbs light at 450 nm very poorly but absorbs much more strongly at 900nm, by about three orders of magnitude and at 10 micron by seven orders of magnitude. (http://www.lsbu.ac.uk/water/images/watopt.gif)
    The preitrance of the two wavelength is directly proportional to the extinction coefficient.
    If an energy packet, say 8w/m2, is delivered to the ocean at 450 nm it will penetrate the ocean about 18 meters before half is absorbed. The absorbed light causes an increase in kinetic energy of the water molecule and the excretion of IR, so that blue light therefore causes deep heating. If exactly the same amount of energy were delivered at 900 nm half will be blocked in the first 2 cm. This is the reason that water looks blue, red light is absorbed.
    IR radiation from atmospheric CO2 re radiance will be half absorbed by the first 2 microns of the surface. This absorbance will be enough to kick some of the molecules on the right of the Boltzmann curve, further to the right, giving them escape velocity. So red light and IR will increase the evaporation of the water, but have little effect on the temperature, because of lack of prenitrance.
    This means that light in the blue end of the visible band will tend to heat the water in bulk, whereas the red and IR will only “heat” the surface.

    “3)Heat is transfered from the surface to the depths by ocean currents. One consequence of all that warm water evaporating is that the water on top tends to be saltier, and this increases density. After the water flows north a bit and cools, it is heavy enough to sink down to the even colder depths. This is what drives the Gulf Stream, for instance.”
    Why is heat not conducted? Why does water have such a heterogeneous temperature profile that correlated with depth? What happens when heat is injected at depth?
    This last one is very interesting as near high temperature undersea vents the temperature gradient can be 100 degrees cm-1. Is it possible to heat the deep water or is heat exchange to the surface too fast?

    4)The oceans are heated by all the radiation they absorb, not just the IR. Basically the oceans will be heated to the point where they are in thermal equilibrium with the atmosphere and the radiation field above them. Increase the temperature or the radiation and the oceans will heat more. This is one of the things you can find out in text books and journals.
    See my response 3 and 4. How is heat transferred up and down the oceans?

    5)I can’t quite figure out what you’re asking here. If you want to know how much of the IR radiation at the wavelength of CO2 absorption will be absorbed if said photons are incident on the ocean, the answer is all of it. Radiation is radiation. Radiation is not radiation, see reply to 1).
    “It is a fundamental principle of quantum theory that all photons of the same energy are indistinguishable.”
    It is also true that both you and a pack of howling baboons are examples of solutions to Schrodinger’s wave equation, but that neither here or there.
    “What CO2 does is increase the energy that stays in the atmosphere. That warms the whole planet–oceans and all.”
    The question is if CO and water help ensure that heat the reach the surface of the atmosphere ground interface is recycled by bouncing back outgoing IR radiation, why does not the same system exist under the seas?
    There is more water and CO2 in the oceans than in the atmosphere, so why is not IR radiation from the sea bed not continually recycled so that the oceans boil away? No IR radiation form the blackbody radiation of the seabed will ever be able to escape, so where does this energy go?

    6)Why would there be such a runaway heating? Most of the oceans is insulated from what goes on at the surface by the warm layer above it that absorbs all the light.
    You see, even you can recognize that only the surface should warm up, increasing evaporation, not heating.

    “If you want controlled experiments, stay in the lab.”

    I work in the lab almost six days a week and all my experiments have the appropriate controls.

    “The rather sizeable sum your experiment would cost would be better spent on experiments, modeling and satellite missions that would tell us something we don’t already know.”

    I had always though that Billions were being thrown at climate science, so I wondered why the guys and gals never bother to conduct any actual experiments.

    [Response: I’m not really sure I want to jump in here, but the preferential absorbtion of different wavelengths in the ocean is pretty well understood , and while it does make a difference, it has no particular impact on the uptake of heat by the ocean in climate change experiments. Secondly, lots of ‘actual experiments’ are conducted in climate science – both in the lab and in the field. They can be challenging, but that’s never put off determined people. – gavin]

  45. 145
    Michael says:

    A funny read… a sense of humor certainly helps in something that is as hotly debated as global warming.

    I once listened to a very stimulating talk about Charles Darwin and the theory of evolution. It was given by an entomologist who naturally looks for genetic relationships among insects. He made a comment that I think applies to this debate about global warming: “Let’s stop pretending we know more than we really know.”

    Let’s face it… global climate models, though they may be “physical models,” certainly don’t resolve all of the physics when they operate at resolutions on the order of 100s to 1000s of kilometers. When you can’t resolve physics, you are forced to make assumptions and create ways to represent the physical processes that you think are important. So, let’s be honest about the global climate models, we still have a long way to go, and one questions whether or not we ought to be making decisions that will cost our society billions and trillions of dollars based on these “physical” models. Our technological growth has occurred because we have had access to inexpensive power, which in the U.S. means coal power. And to think of all the CO2 that is dumped into our atmosphere running the supercomputing clusters that produce our global warming predictions!!!

    By the same token, we shouldn’t rule out theories of anthropogenic global warming based solely on solar activity observations. Without skeptics, or a reason to question, the motive for discovery is lost. To the global warming scientists out there, be grateful for the skeptics. Their questions make your efforts valid, and drive the quest to learn more about how our climate works. My sense is that we still have a lot to learn.

    Thanks to those on this blog who try to explain this science to the world. I’m an engineer, not an atmospheric scientist, so it helps to have people in this community point out the recent papers in the literature that are interesting and relevant, where one can go to learn more about the science.

  46. 146
    Timothy Chase says:

    Ray Ladbury (#138) wrote:

    James, if you read the essay by Helen Quinn, that is pretty much the argument she is making. I was not advocating the use of “I believe” over “I know”–merely giving historical perspective.

    Tim, I strongly recommend the essay.

    Belief and knowledgeâ??a plea about language
    Helen Quinn
    http://www.physicstoday.org/vol-60/iss-1/8_1.html

    Since I am at work at the moment, I only had the chance to look over it quickly, but I believe I am in agreement with it.

    The definition of knowledge I operate by is the old standard often attributed to Plato: justified true belief.

    Of course, justification isn’t usually a matter of either something being justified or not. Typically it is a matter of degree rather than kind, so at this point the question becomes, “How much justification before something counts as knowledge?”

    There is no easy answer to this question, but obviously we would want the probability (assuming we are thinking in those terms) to be more than 50 percent – preferably a good deal higher. But if someone were to deny that something is known unless it were justified to such an extent that no evidence could ever count against it, then in logic they can claim no knowledge. But in my view, radical skepticism is self-referentially incoherent (essentially self-refuting), therefore we must admit of knowledge even where, at least in principle, some evidence might count against it. Essentially a rather vanilla view. The twist is basically in regarding the framework for such an approach as incorrigible. Twisted like a Mobius strip.

    Anyway it looks like we agree on the important points.

    Not that it would matter all that much if we didn’t. No doubt there would still be plenty that we agreed on – like the necessity of doing something about climate change. Somehow I think that issue is a little more urgent than where one stands on the synthetic a priori or self-referential argumentation – at least for the foreseeable future.

  47. 147
    ray ladbury says:

    Re 144. Michael, isn’t it interesting that whenever someone comes out and says that the climate models suck and we really don’t understand climate, they are almost invariably NOT climate scientists? First, the attribution of climate change to anthropogenic greenhouse gas emissions does not in any way depend on the detailed climate models. There simply is no other mechanism that could explain it. Second, the climate models work. They nailed the effect of Mt. Pinatubo. And they have been invaluable in understanding what is actually going on. I think that it should tell us something that whenever there has been an experimental result that conflicted with model predictions (e.g. cooling of the oceans or discrepancies between tropospheric and satellite measurements), it was the experimental result that was in error. Moreover, when the models have been wrong, it has been because they were too conservative.
    Finally, WE ARE CHANGING THE CLIMATE, AND WE WILL HAVE TO DO SOMETHING ABOUT IT. So you’d better hope the models work, because otherwise we will be flying blind. Without the models we have no idea how much we need to cut ghg emissions, how close we might be to tipping points or whether particular mitigations will have any effect.
    So maybe before you suggest that we not claim more than we know, you ought to learn what we in fact do know.

  48. 148
    ray ladbury says:

    DocMartyn, What matters is energy absorbed. And if the same amount of energy is absorbed at 900 nm or at 450 nm, it has the same effect ultimately. It is true that the initial effect of energy absorbed by a vibrational or rotational band will be vibration or rotation. However, that will ultimately get turned into heat.(Look up equipartition.) Yes of course water gets heated by volcanic vents (it doesn’t usually boil, though, as the pressure is too high). However this amount of heating is negligible in the energy balance of the oceans.
    As to why you don’t get a runaway greenhouse effect in the oceans–you’e already answered your own question: the skin depth is too shallow. The light never penetrates to the deep oceans. And conduction is not a particularly effective mode of heat transfer, as it only acts at the boundary layer.
    I really can’t imagine you working in a lab. Not only do you not have an inkling about science, you don’t even realize what you don’t know.

  49. 149
    Hank Roberts says:

    Gavin, thanks for continuing to note when you see that misstatements are being made on a sustained basis.

  50. 150
    FurryCatHerder says:

    Re #145:

    Our technological growth has occurred because we have had access to inexpensive power, which in the U.S. means coal power. And to think of all the CO2 that is dumped into our atmosphere running the supercomputing clusters that produce our global warming predictions!!!

    Fortunately we have access to a lot of very cheap energy through conservation and increased efficiency, and we also have reached a point where renewable energy is cost-competitive with fossil based power.

    There was an article in this morning’s paper about the switch from incandescents to fluorescent lights. Supposedly we could cut 80 coal plants’ worth of power by switching. The Great Plains have enough wind to power the entire country. Waste stream biomass is being deployed more and more often and also produces energy cost-competitive to fossil fuels.

    The need for cheap coal power no longer exists, and if people persist in using fossil fuels, it will cease to be cheap.

    The “but we need cheap power” mantra is more about fossil power producers needing to stay in business. It has precious little to do with “needing” power.