Oh, ok, right, jshore, I’ll just stand here and wait while you look for that … should I hold my breath while I wait for you to come up with this study, or will it be a while?
And while we’re waiting, consider this. After people on the Straight Dope Message Board repeatedly claimed that anthropomorphic global warming was a huge danger, someone apparently did some research in one of those media databases to see which single message board had the largest number of scientifically incorrect claims about global warming. Want to guess who it was? None other than the Straight Dope Message Board itself.
I finally managed to dig the story that I was thinking of. It turns out that I misremembered somewhat what it was about, i.e., it did not involve the media as a whole but only CNN in particular:
I don’t get this complaint. Why is it necessarily a good thing for media coverage to be “balanced”, even if it is discussing an issue where one side of the debate is far more scientifically credible than the other?
If I were reading media stories about, say, evolution, and 41% of the stories supported evolutionary theory while 53% presented balanced coverage of evolution vs. creationism, I would definitely consider that a case of media bias against evolutionary theory. Because creationism is much less justified scientifically than evolution is.
Similarly (although to a lesser extent, natch), claims that anthropogenic climate change is occurring are better supported scientifically than claims denying it. Sure, climate-change skeptics can successfully critique details of the anthropogenic hypothesis as an explanation of global warming (and of course should be encouraged to do so, since that’s how science makes progress). But unless and until the skeptics come up with a non-anthropogenic hypothesis that explains the evidence equally successfully, they don’t really have a scientific debate; they just have a list of (comparatively minor) suggestions for improvement.
Sorry, that’s not how science works. It’s not necessary to propose an alternative hypothesis in order to disbelieve in some hypothesis. In the 1600’s, although the composition of the moon was not known, it was still not widely believed to be made out of green cheese.
In fact, in a subject as poorly understood as the climate, it may not even be possible to present an alternative hypothesis … it may be caused by something like a change in a combination of DMS, albedo, and the solar wind, but the truth is, we don’t know.
Since there is very little evidence for the CO2 hypothesis (bear in mind that a computer can be programmed to give any desired result, so model results are not evidence), the onus is not on the people who don’t believe the CO2 hypothesis to disprove it, but on those who believe in the hypothesis to substantiate it.
This will be somewhat difficult, given that for a good part of the time (about 1945 to 1975, and 2001 to 2006) CO2 levels were rising steadily, while the temperature was dropping or staying level. This is explained away by those who believe in AGW as being due to aerosols, but that doesn’t even pass the laugh test. That’s because the aerosols are concentrated in the northern hemisphere, but both hemispheres cooled. If the “CO2 is the main driver of climate, except for the aerosols” theory were correct, the Southern Hemisphere should have shown a different response than the Northern … but it didn’t. And why has there been so little warming in the Southern Hemisphere?
Also, CO2 theory proposes that the poles will warm faster than the equator, but while the North Pole has warmed, the South Pole has not. And why have the oceans cooled in the last couple of years, and not warmed much in the years before that? (References available upon request, it’s all in the scientific literature).
Here’s another question. Much is made of the fact that temperature and solar irradiance were quite correlated until about 1980, but have “decoupled” since then. This is taken as “proof” that CO2 is to blame, because we don’t have an alternative explanation for the recent warming, of the type you are requesting. Here’s the problems with that kind of reasoning.
One is that there is very little in the field of climate science that is agreed upon as solid fact. One of the things which is least resistant to criticism is the metric we are discussing, the continued increase in global temperature since 1975. Phil Jones (of the HadCRUT temperature record) has refused to open his data to public view, which means that it is worthless scientifically. There are a variety of problems with the individual ground stations, which are known to exist but whose total effect is unknown. There is an unknown amount of urban (more properly local) warming. There is no central documentation of the history, location, and layout of the world’s ground stations. In short, we don’t have a good grasp of even the dimensions of the divergence you are asking people to explain.
Another problem is that air temperature is a horrible metric, because it does not measure the energy in the air. To do that, you need to include the amount of water vapor in the air, and we have very poor figures on that.
Even ignoring the water vapor issue, we don’t even have any agreement on how to measure the “average global temperature”. Should we use area-averaging, or EOF averaging? Should we average the whole world, or average each of the hemispheres individually and then average them (the more common method)? How do we deal with gridcells where there is only fragmentary data? For coastal areas, should we use the ocean temperature or the land temperatures? For the ocean, should we use the air temperature records, or the sea temperature records? How do we deal with gridcells that contain a great variety of microclimates, perhaps at different elevations? How do we adjust for the fact that as we go further back in time, the number of stations changes? How do we deal with missing data? How do we adjust for the fact that for a good chunk of the world, we have absolutely no temperature data at all? How many daily records must be present in a month, or in a year, to say we have enough to use? Each of these questions has no inherently “correct” answer, and each one has its scientific proponents and detractors. Thus, even the question about how much the temperature has risen since 1975 can’t be answered.
Beyond the difficulties of measurement and measurement error, our understanding of the climate is very primitive, simply because the climate is so complex. Climate is an immense, multi-stable, driven, chaotic, optimally turbulent, constructally organized tera-watt scale heat engine, with dozens of forcings and feedbacks, both internal and external, and both known and unknown. It is composed of five major subsystems (ocean, atmosphere, lithosphere, cryosphere, and biosphere), none of which are well understood. Each of these subsystems has its own forcings and feedbacks, again both known and unknown, which affect both itself and the system as a whole.
In addition, because of the sheer size of the system, our measurements of the various phenomena have large error margins. Even with satellites, we don’t have good figures for such basic things as total upwelling radiation at different frequencies, the albedo, global average downwelling radiation, or the temperature of the lower atmosphere. Our scientific understanding of complex, chaotic, driven, turbulent systems is so poor, and our measurements are so uncertain, that we can not predict the next month’s weather or the next decade’s climate in anything more than the most general terms.
Despite (or perhaps because of) this lack of knowledge, the ugly truth is that many climate scientists seem extremely reluctant to say “we don’t know”. As a result, the mystique has grown up that we understand the climate, and people like yourself and others expect or request that we explain short-term (25 year) fluctuations in the climate. Unfortunately, given our current state of knowledge, this is not necessarily possible.
Take for example the effects of the solar magnetic field on climate. This effect is known, but is very poorly understood. Is it responsible for the recent warming? There is much current scientific investigation of this question, but still, we don’t know.
This is separate from the effect of solar coronal mass ejections and the solar wind on climate, which is even less understood. And all of that is made even murkier because it is the interaction between the earth’s magnetic field and the solar magnetic field which shapes the final field, and that interaction is poorly understood.
Or how about the effect of land use changes? NOAA has said publicly that they may have a greater effect than CO2 changes. Are they responsible for some, part, or all of the recent warming? We don’t know.
It is well known that there are a variety of short-term (multi-decadal) oscillations or shifts in the climate system, such as the Pacific Decadal Oscillation, the Arctic Oscillation, the Atlantic Multidecadal Oscillation, and others. These have significant effects on the global temperature. Could one of these, or a combination of these, or other unknown natural oscillations have caused the recent warming? We don’t know.
Methane is not a well-mixed gas. Levels vary all over the world. It has recently been discovered that plants emit methane, perhaps a third of the global totals. This methane is concentrated in the lowest levels of the atmosphere. Worldwide, the planet is greening. What effect has this had on the instrumental temperatures, which are measured in the lowest layers of the atmosphere? We don’t know.
It has recently been discovered that plankton emit a gas (DMS) that cause the formation of clouds above them. What effect does this have on the climate? We don’t know.
How much has the sun’s irradiance changed since 1975? Despite satellite records, there is scientific dispute about that question as well, because of the lack of overlap between satellites that have given very different answers.
What about the electrical effects? The tops of thunderstorms are electrically charged to about 6 kilovolts compared to the bottom … what effect do changes in that electrical potential, which is modified by things like the solar wind, have on the total energy released? And how is that accounted for in the models? … oops, forgot, the models don’t have thunderstorms …
How about albedo changes? Could they have caused the temperature changes? Unfortunately, again, we don’t have good measurements of the albedo either, so we don’t know.
Finally, how do these (and a host of other forcings and feedbacks) affect each other? What happens if a swing in the PDO occurs at the same time as a swing in the cosmic ray intensity, or any of hundreds of other possible interactions? This we really, really don’t know.
In fact, of the 12 forcings listed by the IPCC in the Third Annual Report, the “Level of Scientific Understanding” (LOSU) of nine of them is rated as “Low”, or “Very Low” … that’s a very poor understanding of the majority of the forcings (and doesn’t even include some known forcings, or any of the forcings we haven’t discovered), yet despite that, people like yourself say “explain the historical record”. Sorry, but … we don’t know.
Now, faced with this lack of knowledge, the standard response from the AGW crowd is “it must be CO2? … but why must it be CO2? Not knowing is certainly not proof of anything. In addition, the change doesn’t fit the theoretical model of CO2 effects. Why would CO2 cause very little effect until 1975 (as evidenced by the close correlation between solar activity and temperature up to that point) and then suddenly cause a large effect? Why would the sun suddenly stop affecting the temperature in 1975? We don’t know, but saying “we can’t explain it, so it must be CO2? is nonsense.
So, despite the existence of a wide variety of possible explanations, I regret that I cannot offer you any solid hypothesis about what caused the divergence. We don’t even have any evidence that is resistant to criticism regarding whether the divergence is of the claimed size. It is one of the many, many unsolved mysteries of the climate.
However, the fact that I don’t have an alternative hypothesis does not prove that your hypothesis is correct. All any of this proves is that there are still many, many things about the climate we don’t know.
Finally, given the amount of scientific uncertainty, given that actual studies of climate scientists reveals wide disagreement on these questions, given that a number of those who disagree with the AGW hypothesis are PhD scientists with dozens of peer reviewed publications, given that even scientists involved in the UN IPCC process disagree with the what the UN says, given the UN IPCC’s ugly habit of freezing out world-renowned scientists who don’t believe the revealed AGW wisdom, given that the IPCC has publicly stated that they will change what the scientists say so that it matches what the politicians say, given that the debate continues both here and around the world, I find the AGW supporters calls for media censorship under the false flag of “balanced reporting is unfair” to be pathetic, but all too typical.
w.
PS - there is an unfortunate tendency by AGW supporters to echo Bush’s widely (and properly) reviled line that “if you’re not for us, you’re against us”, as though this were a binary debate, CO2 on one side, “Not CO2” on the other. This is not the situation at all.
Have humans had an effect on the climate? I, and most scientists, would say yes. But that’s not the question. There are actually two unresolved questions, “how?”, and “how much?” There is a lot of evidence saying that one of the main culprits is black carbon (soot), not CO2. There is a lot of evidence saying that land-use changes have been the major factor. Aerosols are likely a factor, but our understanding of aerosols is very poor. There is also a lot of evidence that natural forcings play a major role.
These are more than theoretical questions. If we spend billions, perhaps trillions, to reduce CO2 only to find out that the real culprits were black carbon and land-use change, we will have committed an enormous crime against our children and the poor of the world.
Even among scientists who believe that there is a discernible human influence on climate, there is wide disagreement about “how” and “how much”. In this situation of great scientific uncertainty, calling for an end to balanced reporting is a sick Orwellian joke.
Which may well mean that there were a bunch of idiots making stupid arguments against AGW; about it, just not in favor. Sounds rather like what’s happened recently…
This is a quite odd thing to have said; computer modelling may not be particularly accurate or reliable in some cases, but it very definitely is not about ‘programming to give a desired result’.
Mangetout, people on both side of the aisle agree that the models are “tuned” to reproduce the past temperature trend … aka “programming to give a desired result” …
Do you seriously think they reproduce the past temperature trend based on fundamental physical principles, when the effects of the forcings have huge error margins? Of course not. They adjust the effects of the various forcings, and tune the various parameters in the model, to get the results they desire, even the modelers admit that. Here’s a quote from Gavin Schmidt, one of the NASA programmers on the GISS climate model:
Tuning a model to try to get it to mimic known/observed conditions is necessary just to try to make the model realistic - it’s not at all the same as programming it to achieve a desired result - if that were the case, there would be no point at all in running the model.
I think you might have hit the nail on the head there.
You, Intention and I are all, I believe, programmers and that gives us a certain insight into ‘models’.
For my sins, the last ‘model’ I wrote was deliberately designed to provide authoritative looking output that could be (ahem) manipulated by an adept user.
The Treasury, or is it the Bank of England, have something similar (well they did about 30 years ago) which they hired out to people to influence their ‘expectations’.
Well, I am happy to see you quoting from RealClimate given that I know how highly you regard it. However, I only think it is fair to present Gavin’s entire statement (with emphasis added by me):
Mangetout, thank you for your post. The problem is best illustrated by the fact that the models all include a different number and type of forcings. Some include solar, some don’t. Some include volcanoes, some omit them. Many don’t include black carbon, none include vegetation derived methane or solar magnetic variation, many don’t include sea salt or land-use change, none include natural changes in the biosphere, none include plankton-forced changes in albedo, only a few include mineral dust, the list goes on and on.
Since they don’t contain all of the forcings, they have to tune the models (to make them “realistic”, as you say) … but in reality, since they don’t use all the forcings, or even the same forcings, they’re adjusting them with artificial numbers, parameters, and flux adjustments, twisting the model output to get the desired result, which in this case is a fit to the historical record. All of the models are more or less successful in replicating the historical temperature trend, which (given the huge differences in the forcings used) gives you some idea of how much twisting is going on.
But that’s just a parlor game. The problem is, when you force a model to reproduce historical results in that artificial manner, you end up with a model which can’t be trusted to give you real results based on physical principles, because it has been bent out of shape through adjustable parameters to give the desired result of historical realism. The right way to go about it is to describe the physical processes well enough to replicate the past without any parameters … but unfortunately, we don’t understand climate well enough to do that. For some of the forcings, we don’t even know if they’re positive or negative, much less their actual size, and we have almost no knowledge of how the forcings interact. So we patch it up with parameters.
The end result of this path of parameterization was stated very clearly by Freeman Dyson , reporting on his conversation with Enrico Fermi:
You may be impressed that the models can wiggle their trunks … I fear that I am not. Unfortunately, you are correct — as you say, there is no point at all in running the models as they are currently structured.
jshore, thank you for presenting the full quote, wherein Gavin says that the number of major parameters is “3 or 4”, and that overall there are “dozens” of parameters.
However, he does not count as parameters such things as limiting the months when melt water can accumulate on sea ice, as is done in his model … look, if the model were physically correct, there would be* no need to *limit the time when melt ponds could form. Since the model isn’t physically correct, rather than fix the model, they simply limit the time of pond melt formation to two months … which in my book, and Enrico Fermi’s book, is a parameter, but isn’t a parameter to Gavin. Counting all of the parameters in the GISSE climate model that Gavin programs, there are dozens and dozens. See Enrico Fermi above for the results of this kind of use of parameters in the description of physical systems.
In addition, when the parameters used give impossible results, they just put up a limit to stop the model from running off the rails. Don’t believe me? Try this one, again from Gavin Schmidt:
Getting physically impossible results (negative masses? say what?) from your parameterization? Hey, no need to fix the underlying problem so it doesn’t produce impossible results, just put up a fence to keep the model from going off the rails …
With “dozens” of parameters in the model, as I said to Mangetout, I fear I’m not impressed.
All the best,
w.
PS - I’m still waiting for either a citation for your claim about the media giving more mention to Michaels than any other climate scientist, or an acknowledgement that there is no basis for the claim and it’s just an urban legend.
PPS - here’s a list, again from Gavin, of some of the parameters in the GISSE model:
• stratospheric semiannual oscillation
• high-latitude sea level pressure
• zonality of the flow field
• gravity waves
• hygroscopic aerosol radiative properties
• thermal fluxes
• clouds
• optical depth
• melt pond extent
• evaporation of cloud droplets
• pressure-velocity and pressure-temperature correlations
• water vapor conductance
• turbulent heat and mass flux in ice
• ice albedo
• non-local turbulent mixing
• all sub-grid scale items, including such important phenomena as thunderstorms
Short version: it doesn’t really sequester carbon.
Slightly longer version:
Oceanographers talk about “primary production” and “secondary production.” Basically, you can say PP comes from the introduction of new nutrients to the system, while SP makes use of nutrients already there in the form of dead organisms, waste products, etc. Iron seeding appears to increase SP, without affecting PP very much. What this means is that, although there is a higher level of production, new nutrients (i.e. the carbon you want to sequester) are not really being used. Thus, iron seeding does not appear to be a viable means of removing carbon (dioxide) from the atmosphere.
Fascinating stuff-I knew the models were complex, but the detail is staggering. anyway, a question about dsertification; human activities have been implicated in the advance of deret areas. It is clear that grazing animals can destroy plants which provide stabilization of the soil, once removed, the soil can dry up and blow away. My question: have humans had much effect upon the advance of the sahara Desert? or is the drying of that area largely due to natural effects? What happens when humans (artificially0 alter derts-suppose the Isarelis were able to irrigate and reforest the barren lands-would this change the climate of the ME? Or would this have no effect. I’m wondering about the reforestation of N America-a centurty ago, most of Vt and NH was cleared sheep and cow pastureland-now the forests have grown back-has that made these areas colder or warmer?
Thanks for elaborating on the point, intention, what you’ve now explained is a little different to what I initially took you to mean. By ‘achieve a desired result’, I thought that you meant the accountant’s ‘What do you want the end result to be’, rather than achieve the desired result of approximating certain behaviours a real-world system in a vastly simplified model, then using that model to make predictions that may be unsafe because of the simplification.
intention: Thanks for your many posts above. I don’t really have time to respond in the detail they deserve (at least right now, during my lunch break!) but I did want to make a proposal to you. – If you believe that one can “tune” the parameters in the model to get essentially any answer you want…or at least to get good agreement with the past climate record, why don’t you simply demonstrate this? I.e., take a climate model and reproduce the global instrumental temperature record over the last 150 years without the inclusion of anthropogenic forcings! If you succeed in doing this, you could also then compare how well the model reproduces various other characteristics of climate (such as fluctuations, spatial variations both across the globe and vertically) relative to a climate model that reproduces the global instrumental temperature record with the inclusion of anthropogenic forcings.
Sure, you’re allowed to disbelieve in some widely-accepted hypothesis even if you can’t propose a better alternative. Heck, you can disbelieve in the theory of gravitation if you like: it’s a free country. But you can’t claim to have credibly debunked or refuted the accepted hypothesis unless you’ve either (a) provided an alternative hypothesis that does at least an equally good job of explaining the data, and/or (b) convincingly shown that the accepted hypothesis is scientifically untenable.
And so far, climate-change skeptics haven’t managed to achieve either of those goals in their criticisms of the hypothesis of anthropogenic climate change. The skeptics have come up with a number of valid objections concerning the precision, details and reliability of the ACC models (and good on them for that), as well as a number of stupid and erroneous objections that have helped to confuse the popular debate (for which not so good on them).
But nobody has provided a convincing argument either that the anthropogenic-warming hypothesis just can’t work scientifically, or that some non-anthropogenic hypothesis works better. Unless and until some climate scientist(s) can come up with such an argument, the anthropogenic-warming hypothesis remains the best answer we’ve got. I completely agree that we need to improve our understanding of climate science, but I don’t agree that the presence of some uncertainty requires us to eschew all action until all or even most of the uncertainty can be eliminated.
And if we don’t reduce CO2 and CO2 is the major culprit, then we will also have committed an enormous crime against our children and the poor of the world. Whichever policy choice we make, we run the risk of making a very costly mistake. Which is why, IMHO, we should base our policy choices on the scientifically best hypothesis that we’ve currently got, which is the anthropogenic-greenhouse-warming hypothesis.
Moreover, it seems that you’re over-focusing on the question of what effect humans have had on the climate, and ignoring the question of what effect we will have. If human-generated changes in the composition of the atmosphere could be somehow magically halted at their current levels, then I would be much more willing to agree with you that we have time to investigate all the other climate forcings more thoroughly before we contemplate drastic changes to our emissions policies.
But alas, that’s not the case. Humans are continuing to raise atmospheric concentrations of CO2 with ever-increasing emissions. Nobody has yet provided any convincing rebuttal to the basic anthropogenic-greenhouse-effect hypothesis: namely, the more we raise the atmospheric CO2 concentration, the more likely it is to produce global temperature increases. In other words, even if it unexpectedly turns out that our greenhouse-gas emissions haven’t yet caused significant climate problems, the more of them we keep pumping out, the more likely significant climate problems will become.
However, I only think it is fair to present Gavin’s