Another open thread. OT comments from the Amazon drying thread have been moved over. As usual, substantive comments only please and no abuse.
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844 Responses to "Unforced variations 3"
Ric Merrittsays
Patrick 027
@ 23 March 2010 at 7:23 PM —
Thank you for all the details. Knowing the theoretical targets that limit devices is a wonderful thing. The real questions come in that rich middle ground between physics and engineering (not to mention human factors, which may also be decisive).
Trying to concentrate solar power, for example, is a plausible step, and may be economic. To do it on the real Earth, living in our actual society and economy, you have to make small proofs of concept, then raise enough capital to try it at scale, which is approximately where we are now. The early attempts will understandably be far too expensive, but one hopes to do better with experience and economies of scale.
Let’s say this goes reasonably well, with some investment capital from private or government entities we hope will prove far-sighted. Keep in mind that all the while you are building the wonderful mirrors and towers, or whatever your scheme uses, mostly with fossil fuels. This of course is drawing crucial resources from other crucial projects, like keeping humanity alive and worth living, so the competition is fierce. And you are very proud of your particular scheme, but let’s face it, some of those other dunderheads are wasting those precious, dwindling resources on blind alleys. Perhaps ethanol from corn, or tar sands, are blind alleys, for various reasons. And you have to admit, the mirrors and towers are pretty expensive. (Windmills also concentrate solar power, of course. All the same reasoning applies to them, mutatis mutandis.)
But we aren’t even halfway to the promised land yet. Now that your scheme is showing some hope, start doing it over and over, replicating it worldwide, with less and less fossil fuel, eventually none to speak of. That’s the part nobody knows will work. Counting on being constantly richer (Lomborg’s forehead-slapping error, though he is not alone) is circular reasoning. What if we stop getting richer? We’ve proved previously that we don’t need Peak Oil to get seriously messed up by greed, pyramid schemes, political-economic corruption, and the 4 Horsemen. You have to wonder how all that will feed back when Peak Everything and climate change are thrown in. How will that investment buildup, economic restructuring, and electrification of transportation go in times of decline and war? If you aren’t worried about that, you aren’t thinking.
Also, even if the human factors go better than expected, we lack even a proof of concept showing how much net useful energy can come from renewable technology without using fossil fuels. That’s pretty tough to model. We know at least a little is available, because it’s been done, with wood and dung and muscle built from photosynthesis. We’d like to do better than that. I think you just have to try it. Until we get further down the road, we won’t know where it goes.
This sort of topic can get gloomy. I’m not in favor of dropping dead, and I am in favoring of thinking and caring and doing the best possible with what’s at hand. Assuming that constantly increasing wealth comes from technical knowledge is dangerous. We don’t know what percentage is actually due to fossil fuels.
BPL, 341 “Some renewables are now cheaper than fossil fuels”.
The figures I found so far agreed more on less on this: 0.05$ per kWh for the oil (at 70$ a barrel) and around 0.3$ per kWh for solar energy. (coal is even a lot cheaper, about 0.01$ per kWh).
So that we have a factor of at least 6.
You are saying that this factor has now been reduced to 1? Are you talking about solar panels? Can you direct me to some studies showing that?
Many thanks
John Petersays
HR@329
Thanks for your interpretation, it’s very interesting to me, I’ll re-read Mike’s initial description and see if I can understand it. In any case thanks again for your contribution to my education. (I’m trying to understand what a “regional model” really is and there seems to be a lot of fairly high powered statistics to crawl through).
I apologize for not being clearer about Mike’s interview. What caught my attention were some questions and answers at the end; the interviewer and Mike were in a fast paced Q&A. To make it easier so there’s no mistake about what Mike said I’ll reproduce it here:
Interviewer – Robert Frederick
Now, as the title of your team’s paper makes note, the time period that you and your team analyzed includes the Little Ice Age and the Medieval Climate Anomaly. Interviewee – Michael Mann
Right. Interviewer – Robert Frederick
When are those periods? And, according to your team’s model, what happened? Interviewee – Michael Mann
So, the complication sometimes in defining those periods is that, unlike the recent warming of the past century, past periods of warming or cooling tend to be very heterogeneous regionally. That means that if one region was relatively warm, there’s a good chance that other regions were cold, and vice-versa. because of that, it means that it’s actually somewhat of a challenge to define, in a global sense, the Little Ice Age or the Medieval Climate Anomaly. What used to be called the “Medieval Warm Period,” most Scientists favor now the use of the term the “Medieval Climate Anomaly” for the reason that I just cited, that it wasn’t warm everywhere, and that’s very clear in our own reconstructions. So, these intervals are a challenge to define because they are so spatially, they’re variable regionally. The warming and cooling happens in different places and different times, but if you look at, say, the average temperature over the Northern Hemisphere, there is a period of somewhere between the 9th century and the 13th century where temperatures were relatively warm compared to subsequent centuries, and, in fact, a period during the, roughly the, say, the 17th century to the 19th century, or somewhere about there, where temperatures averaged over the Northern Hemisphere were relatively cool in comparison with that Medieval Period. But if you look at theMedieval Period, even though it was relatively warm compared to that Little Ice Age, it compares, in a global sense, at most with the level of warming that we saw in the mid-20th century. It doesn’t reach the levels of warmth that we’ve seen in the most recent decades, at least globally. So we used those two intervals characterizing overall when it was relatively cool and relatively mild averaged over the Northern Hemisphere to define the intervals that we would call the Medieval Climate Anomaly and the subsequent Little Ice Age, and then we looked at the spatial patterns of those time intervals. Interviewer – Robert Frederick
What aspects then, more precisely, of your team’s model of the past may help in predicting current climate change? Interviewee – Michael Mann
Well, there are really two very interesting observations in the reconstructed patterns that we were actually able to test against climate model predictions. And so, we took those same periods – that Medieval Climate Anomaly period and the Little Ice Age period –and we know, imperfectly, but we have some idea of what the level of natural factors that influenced climate in the past, we sort of know what those factors were. We have a good idea of how the output of the sun has varied over the past thousand years, although there’s some uncertainty. We have a fairly detailed record of the history of explosive volcanic eruptions. And so, these are two natural factors contrasting, for example, with the human factor of increasing greenhouse gas concentrations. These are natural factors that influence climate over time. And we took those factors and we ran two different climate models with the estimated difference in the levels of volcanism and solar output in those two different intervals – in the Medieval Climate Anomaly and the Little Ice Age period. One of the models is the NCAR-coupled model. The other model we used was the NASA Goddard Institute for Space Studies coupled model. So, it gave us sort of a sampling of two different physical representations of the way the climate system responds to these natural factors. And we could look at both of those models, we could see what they predicted, and we could see how it compared with what we actually observed. And what we observed was that the surface temperature patterns during the Medieval era counter intuitive l look more like the La Niña phenomenon, when it’s cold in the eastern and central tropical Pacific. Now, this is a period of time when solar output was relatively high, there was relatively little explosive volcanism, so there was a net heating of the global climate, it was a relatively warm interval, and yet those same factors appear to have drove the climate not into the warm El Niño state of the tropical Pacific, but the cold La Niña state, a bit counterintuitive. We also saw in the reconstructed pattern, that when you compared the Medieval era to the Little Ice Age era, aside from the Medieval era actually being cooler in the tropical Pacific, counter- intuitively what we used to think of the Medieval Warm Period, is that it was actually cold in the tropical Pacific in comparison with the Little Ice Age, which is what we normally think of as the cold period. Interviewer – Robert Frederick
So, this is the idea of the tropical Pacific acting as a thermostat. Interviewee – Michael Mann
Absolutely, and we see that in the reconstructions. As it turns out, neither of the two models that we looked at actually exhibit that response. There are only relatively small subsets of coupled climate models that exhibit this tropical thermostat response; most of the models do the opposite. When you warm the tropical Pacific, the models respond with an El Niño-like state, and when you cool the tropical Pacific, they respond with a La Niña-like state. So the majority of the models used in the most recent IPCC projections, for example, don’t favor the thermostat response – they favor an El Niño-like response to a warming at the surface, like the warming that we’re seeing with increased greenhouse gas concentrations. However, the paleoclimate record of the past thousand years, in our analysis, suggests that at least with respect to the response that the climate has exhibited to natural factors, the response appears to be that thermostat response – it appears to be the opposite of what most of the IPCC projection models project.
Interviewer – Robert Frederick
So is it your team’s intention, then, to try to get your model included in the next assessment of the Intergovernmental Panel on Climate Change, the IPCC? Interviewee – Michael Mann
Well, the two models… Interviewer – Robert Frederick
The NCAR and NASA ones are already in there. Interviewee – Michael Mann
Yeah, exactly. So the – yeah, I think that it’s useful, and in the next IPCC assessment, it may very well be the case that there will be a new section that deals with the question of how paleoclimate data can inform our understanding of some of these fairly complex, dynamical responses of the climate. So, while I don’t see our results as being made explicitly part of an IPCC projection, I do see them as potentially informing our assessment of the extent to which we think the current generation models are, or are not, capturing some of the regional mechanisms that may be important in making regional climate change assessments. Interviewer – Robert Frederick
Michael Mann, thank you very much. Interviewee – Michael Mann
Thank you. It was a pleasure talking with you.
This was the time of the climate-gate problems with the MSM; I thought Mike was caught off-guard by the IPCC question but he fielded it very well. He’s one scientist who knows how to talk to the press.
Before your post, I believed I understood this interchange so I posted that understanding. What do you make of it? ;-}
Patrick 027says
Re Simon Abingdon – signal verse noise:
More generally, a signal is any component of the data’s structure that you are ‘looking for’ and noise is everything else. So what is noise and what is a signal depend on what issue you are studying. A cycle can be a signal. The most basic signal of forced climate change is a longer-term trend, which reflects the change in forcing over time plus a lag-time from thermal inertia, etc. If any noise could occur with long-period trends, than the data alone wouldn’t be enough to pinpoint what the signal is, but considering the physics of the noise (how much low frequency noise could there be?) and using multiple dimensions (spatial-temporal patterns, heat content changes) can help tease things out. However, a change in the texture of the noise itself could constitute a signal of sorts.
Completely Fed Upsays
Didactylos, I would think that ending comment would more validly be placed at your feet…
Andreas Bjurströmsays
345 Richard Ordway,
It seems that you never really listen to what I actually say. The same goes for most people I have discussed with here. And your response is very telling for how politicized climate science is and how that results in a trench warfare with very limited options on how to understand and respond to this very complex and broad problem.
Gillessays
BPL :”BPL: Well, I said I’d stop answering Gilles, but this was too stupid to resist.
They dropped renewables for fossil fuels because fossil fuels were cheaper at the time. Some renewables are now cheaper than fossil fuels, and others are becoming so. And the costs of fossil fuels in terms of pollution and damage to peoples’ health wasn’t properly factored into their costs (and still isn’t).”
BPL : if the situation has changed, we should see that in the marginal capacity added each year. So can you remind me which fraction of the increase of energy (except last year where the energy consumption decreased) is brought by renewable energies in the recent years, compared with fossil fuels ?
“”””345 Richard Ordway,
It seems that you never really listen to what I actually say…
and I don´t find your hard core view of scientism consensus very recognizable to working scientists. They usually work in cutting edge areas without consensus..””””
This is ripe. Please present some evidence that there is not a scientific consensus from publishing climate scientists whose work holds up over time.
===========================================================================
CONSENSUS
QUOTE: “A plethora of studies from diverse sources indicates a consensus that climate changes will result from mans’ combustion of fossil fuels and changes in land use.”
1979-National Academy of Sciences Archives, “An evaluation of the Evidence for CO2-induced Climate change, Assembly of Mathematical and Physical Sciences, Climate Research Board, Study Group on Carbon Dioxide, 1979, Film label: CO2 and Climate Change: Ad Hoc: General.
Okay dude. I personally have known many of the world’s top publishing climate scientists whose work holds up over time for over 11 years at the climate research center where I was for 11 years as well as NOAA and EPA scientists… and saw many of them and talked to many of them on an almost daily basis.
They accepted the consensus’s for what it was…written solidly in the peer review, but still willing to keep an open mind. Your ideas are mad.
Patrick 027says
Correction: The formula (1-Tc/Th) * [1 – (Th/Ts)^4] was specifically for dish or other such concentrators that theoretically can focuse sunlight so that at the focus, the flux per unit area would be the same as at the surface of the sun (except for atmospheric effects). It could apply to a parabolic trough concentrator but only if the material at the focus only acted as a blackbody in a limited range of directions… otherwise it might be necessary to … use the square root of Ts in place of Ts (? I haven’t actually done the math yet for that problem).
Ray Ladbury has forgotten more about science than you’ve ever known.
Peer review and consensus is how modern science is done, and it has been a fantastically productive system. Everyone I’ve ever encountered who argued against the idea of scientific consensus was a pseudoscientist.
It’s not prejudice just because someone disagrees with you.
I know how a nuclear plant works. I believe a safe nuclear plant can be built. It’s just that I think it would no longer be cost-effective if it were safe. And the damn things take forever to build. Other options are better. If our options were ONLY coal or nuclear, I’d take nuclear. But they aren’t. Period.
I’m talking about windmills. And possibly biodiesel; I haven’t seen the latest figures.
Didactylossays
Completely Fed Up: No.
Didactylossays
Naindj:
BPL and others sometimes fall into overly-simplistic views on energy cost. The reality is that energy costs vary considerably by country, state – even by individual installation. BPL and CFU will try to push the California figures, and pretend that no others exist. I have yet to see figures for California that properly account for subsidies. You seem to be using whole-US figures. In the US, coal is still very cheap.
I would be very interested if you happen to find any similarly credible sources for global energy costs. I’m not naive enough to claim that the UKERC figures are in any way definitive (but they are the result of academic studies and have no clear bias, unlike most sources of energy cost estimates).
Andreas Bjurströmsays
362 Barton Paul Levenson,
Stephen Schneider shows a rather critical view of the IPCC conservative concensus culture (in his new book). Is he a pseudo-scientist according to you?
360 Richard Ordway,
Ýou still don´t read what I actually say. I was mere contesting that a strong culture of concensus are good for scientific progress. To be critical and question the taken for granted are very important in science.
But sure, I can give an example of concensus and climate change. 100 years ago Svante Arrhenius argued that a warmed climate due to AGW is beneficial for humankind. In the cold war era, many climate scientists in the USA was worried of atomic winter. They also worried that aerosols could cause cooling. And they had a technocratic view on the possibility to control climate (keep it stable). The environmental discource where climate is seen as a problem of the environment started in the 1970´s. The concensus we see today stems from this era, and have been gradually produced. We dont know yet, if the concensus frame of today will change in say 10 or 20 years. I would be very surpriced if we dont understand climate differenty in 20 years time.
Didactylossays
BPL:
You have made your prejudice about nuclear power very clear in the past. And since those previous discussions, you have already forgotten that different countries have different energy needs, and different renewable resources, and different practical constraints.
Proof, if any were needed, that I am talking to someone who has made up his mind years ago, and who is not open to further discussion.
CND? Chernobyl? Who knows what cemented your opinion. If you honestly believed that “a safe nuclear plant can be built”, then you would not argue against nuclear power using emotive appeals to hysteria, patently false claims about financial viability and frankly ridiculous lists of nuclear fatalities.
Perhaps you could use your list of fatalities to calculate your own estimate of deaths per GWY? Don’t forget to exclude the military accidents.
Ray Ladburysays
Andreas says, “Of cource there is a “certain body of knowledge that virtually any researcher in a field must agree upon to be productive”. However, this core body of knowledge change with time.”
Well thank you Dr. Obvious–and you will note that it changed via the efforts or scientists–experts in the field.
Andreas: “Your “concensus is truth” viewpoint can neither explain why scientific knowledge change nor why some important truth can be true one day and false the next.”
Actually, Andreas, first, I never equate consensus with truth. Rather, I state that consensus gives the most reliable approximation of trugh we have at any moment. And my view explains quite precisely why an “important truth” (or rather an approximation thereov) may change. It does so because a new approximate truth does a better job at explaining the phenomena under study. And then to be maximally productive, scientists in that field must adopt that truth–a new consensus emerges.
Moreover, my viewpoint explains why once the explanatory power of a theory becomes sufficiently great, it is very rarely overturned but instead tends to be refined gradually over time. Such gradual evolution is much more common than scientific revolution. It is what we as scientists work at on a daily basis.
Andreas: “If you bothered to pay closer attention to real science, and less to scientific ideology and wishful thinking, you’d know that.”
Actually, Andreas, I not only pay attention to science, I do science. Very applied science, it is true, but it is application of the scientific method. Would you care to name some real scientists who buy into your postmodern [edit]?
John Petersays
BPL@363
Why either/or? Phase the coal out. Phase the nuclear in. Bridge the gaps with solar, wind, biodiesel whatever.
Sounds pretty good to me.
Rick Brownsays
#344 Andreas Bjurstrom, thinking he’s responding to Ray Ladbury #336:
“I am also a real scientist . . .”
Not being a scientists myself, I’ll accept that you are a “real” one. I’ll also humbly suggest that you’ll be a “good” scientist, i.e., contributing to the body of scientific knowledge, when you learn to constrain your highly developed confirmation bias, which has been much in evidence in most of your many postings (generalized, along the lines of “I came to this site and found just what I expected . . .tsk, tsk”). Perhaps you could put it in a blind trust along with your similarly unhelpful, self-described, “warrior” side.
I’m really not interested in encouraging you to post again, so please feel free to consider the following question rhetorical. Where, precisely did Ray L. say that scientific consensus “is truth?”
Phil Scaddensays
“But sure, I can give an example of concensus and climate change. 100 years ago Svante Arrhenius argued that a warmed climate due to AGW is beneficial for humankind. In the cold war era, many climate scientists in the USA was worried of atomic winter. They also worried that aerosols could cause cooling. And they had a technocratic view on the possibility to control climate (keep it stable). ”
I dont agree. Since Arrhenius the consensus is that GHG cause warming. At rate of CO2 production in Arrhenius time, the warming might be well be beneficial but I strongly doubt that he would have thought rapid warming was good. The consensus is still that aerosols cause cooling and your only reason for not worrying about an atomic winter is that risk of atomic war has receded. I’ll be very surprised if the consensus here will change in even 10,000 years time.
John Petersays
Soo@331
It seem pretty simple to me. We do the energy balance easily by looking at the earth and sun as black body radiators sitting in space.
The sun radiates mostly IV radiation at the earth. Some gets reflected to space the rest gets absorbed.
The earth radiates IR to space. At the outer edge of the atmosphere these energies must be equal.
The surface temperature of the earth is warmer (35C) than needed to radiate enough energy balance the sun’s. Enough of the energy radiated by the earth is trapped in the atmosphere to reduce the net earth energy to balance with the sun.
To calculate the earth radiation instantaneous emission is averaged diurnally and over latitudes, pole to pole.
If I have this (nearly) right, I can’t envision doing this average “regionally”
> At the outer edge of the atmosphere these energies must be equal.
When? Why? Says who?
John Petersays
t_p_hamilton@335
Thanks for noticing.
If regional models don’t work too well (yet), I have a problem with the “hot here, cold there” explanation we try to use to explain GW. How do we know who’s hot and who’s cold if our models won’t tell us?
As a physicist
“Paleoclimate comparisons might help, they might not.”
makes sense to me, although Mike’s answer is a little better PR.
Global warming predictors that back-casted successfully would be even more impressive to me as a financial analyst…
Andreas Bjurströmsays
372 Phil Scadden,
You misunderstand me. I don´t argue about “GHG cause warming” concensus. Climate change is a complex of hundreds of different theories and “hypothesis” and facts and speculations and evaluations …
Im not sure why you cherry-pick just one of the most well-established facts as a symbol for climate change as a whole. To disagree with me you must first understand what I was saying.
David Millersays
Naindj (354): Sorry, but I’ve got to call BS if you’re talking about coal fired electricity going for a cent per KWH.
We are talking about a delivered price for new generation capacity, right? A cent per KWH doesn’t cover the fuel, let alone the plant cost.
Citation required if you’re going to stick with that number.
David Millersays
Someone – Tim Jones, I think, opines:
This isn’t necessarily so. If it takes more energy to extract the oil than the oil provides it won’t be worth doing no matter what the price. If the energy returned is less than the energy invested you have a negative ERoEI.
I wish that were so.
Unfortunately, it’s not always so. It is true if you’re using some of the extracted energy in order to extract more.
With in-situ combustion of coal an tar sands, however, the economics picture is very different than the EROEI picture. How many barrels of would-be oil are burned in place is irrelevant to making a profit. All that counts is money invested and hydrocarbons extracted. Burning 3 barrels in the ground for each barrel extracted means the extraction rate is 25%, but it’s worthwhile if there’s a good financial ROI.
Coal is the same deal. They’re already talking about partially burning it for the producer gas output. Coal to liquid! And you don’t even have to remove the top of the mountain first!!
So, from an greenhouse gas point of view, things could get very ugly when oil starts getting expensive again.
“”””Stephen Schneider shows a rather critical view of the IPCC conservative concensus culture (in his new book). Is he a pseudo-scientist according to you?””””
Please give actual quotes from Steve Schneider in your statements. I doubt he or Joe Romm disagree with the scientific consensus that we humans are causing global warming.
________________________________________________________________________
CONSENSUS
1) The USA’s highest science body-1979:
QUOTE: “A plethora of studies from diverse sources indicates a consensus that climate changes will result from mans’ combustion of fossil fuels and changes in land use.”
1979-National Academy of Sciences Archives, “An evaluation of the Evidence for CO2-induced Climate change, Assembly of Mathematical and Physical Sciences, Climate Research Board, Study Group on Carbon Dioxide, 1979, Film label: CO2 and Climate Change: Ad Hoc: General.
_________________________________________________________________________
2) This scientific consensus was repeated by governments of about 120 countries in 1995 in the peer reviewed literature:
QUOTE: “The balance of evidence suggests a discernible human impact on global climate.”
Houghton et al., eds., Climate Change 1995, 5. It’s not hysterical, not catastrophic, …human fingerprint had become scientifically detectible. This was a scientific consensus.
————————————————————————
3) This scientific consensus was repeated in the peer reviewed Science Journal in 2004 by a respected scientist… and the information has held up over time:
QUOTE: “The scientific consensus is clearly expressed in the reports of the Intergovernmental Panel on Climate Change (IPCC)…But there is a scientific consensus on the reality of anthropogenic climate change….In recent years, all major scientific bodies in the United States whose members’ expertise bears directly on the matter have issued similar statements.” Oreskes 2004, Journal of Science.
Study showed that scientists had a consensus that warming would happen since late 1970s…and it did:
_________________________________________________________________________
Why did so many people (nearly ½ Americans) have the impression of a raging debate?
Short answer: That is the impression that a small but powerful group of people, aided and abetted by well-funded think-tanks and a compliant mass media, wanted them to have.
-Peer reviewed Oreskes,- her scholarly book the Merchants of Doubt.
John Petersays
Hank Roberts@374
Hank, you asked:
When? In equilibrium, a day is pretty good, a year would be even better
Who? Probably Stephan or Boltzman. Read Ram’s 0-dimensional model in the 1989 Physics Today Review. Maybe Trenberth around 1997 or any other energy balance description. Out in space radiation in equals radiation out. Otherwise we get hotter or cooler.
Try http://oceanworld.tamu.edu/resources/oceanography-book/radiationbalance.htm
for a more professional description.
@ #373 John Peter says: 24 March 2010 at 6:53 PM
John, I’m thinking you are talking about two issues here. One is the overall extent of global warming (net radiation), being induced by an increase in greenhouse gases and all the follow on consequences of that (ice loss etc). The other is the response to global warming in different regions and localities. There is a lot of work going on in regard to both aspects.
The climate models are able to use smaller grids as computing capacity increases and this should help work out regional changes more precisely.
You’ve got me interested in just how the radiation side of things is variously measured and calculated. I’m so far figuring there are various ways of doing it, using data from satellites and ground-based instruments. The new NASA climate site (http://climate.nasa.gov/) is very good and has a lot of information, but it’s not always easy to find exactly what you want :)
Patrick 027says
Correction for CSP efficiency limits:
The actual limit for concentration of solar radiation (in terms of flux per unit area) is [(distance from center of sun)/(solar radius)]^2 ~= 215^2 ~= 46,300. (I vaguely recall reading that it could be concentrated up to 80,000 times – perhaps this requires some shift in the … I don’t know, it just doesn’t sound right, it would break the second law of thermodynamics; perhaps I misunderstood what the 80,000 specifically measures).
But reaching such a limit for the entirety of the solar flux that is being concentrated may require some nongeometic optics, or at least, something more than a parabolic dish, or a simple lens, so far as I can tell.
Consider for example a parabolic dish, with rays from the center of the solar disk reflecting off the dish precisely onto a focal point. Now what happens to the rays from the limb of the solar disk? If the aperture of the dish is small relative to it’s curvature, then all lines from the focal point to the dish will have nearly the same length, so the rays from the limb of the solar disk reaching different parts of the dish will all make their closest pass to the focal point at about the same distance from the focal point (that distance gets larger for reflected rays from the more distant parts of the dish). And if the aperture is relatively small, the reflected rays from the center of the sun will still be in nearly the same direction, so the rays from the limb will get closest to the focal point while nearly in the plane perpedicular to the axis of the dish (and to the incident solar rays). Thus an approximate image of the sun should be produced on a flat surface at the focal point. However, the small aperture means that the dish covers a small solid angle as seen from this surface; in terms of the flux per unit area, it brings the sun somewhat closer but still far from the theoretical limit.
In order to get to that limit, all points on the target surface would have to ‘see’ the sun in all directions exterior to the target. The dish would have to large enough for the focal point to be within the plane of the dish’s edge, so that radiation reflected off the dish would cover the full hemisphere as seen from all points on the target surface. However, the ‘image’ (if it can be called one?) of the sun produced on this surface by rays reflected from the outer parts of the dish would be larger, and in fact, getting near the edge of the dish, not all reflected sunlight would even reach the surface – near the edge, only about half of the solar rays would reach the target surface at first pass and they would be spread out over an area nearly the size of the aperture of the dish itself (the other rays would be reflected back up after hitting near the edge of the dish on the opposite side of the dish, and they would pass through the target surface mainly near the edge of the dish).
Alternatively, one could have a sphere or ellipsoidal surface at the focus, to better recieve rays from near the edge of the dish. But for a dish of such dimensions that the focus is in the plane of the edge of the dish, the surface recieving radiation from the edge of the dish would only ‘see’ the dish covering about half the ‘field of view’ – the flux per unit area would be half of the theoretical limit; also, in order to capture all solar rays reflected from the dish, the targe would have to extend out to points where reflected rays are only coming from that one part of the dish, thus the flux per unit area would not be so large. The dish can be expanded to increase the concentration; the concentration reaches the theoretical limit when the dish is a full ellipsoid with the other focus at the sun (although a hole in the ellipsoid behind the sun is allowed) – obviously that’s not practical at this point in history, if ever.
Still, the compromises available needn’t fall too far short.
Considering either a parabolic dish or trough, with a flat target surface facing into the dish/trough passing through the focal point/line, just large enough to capture all reflected solar radiation:
—–
With dish aperture radius or trough aperture half-width = a.
distance from center of dish/trough to focal point/line = r.
a/r = g
distance to center of sun = ds
radius of sun = Rs
angle from center of solar disk to limb = q
sin(q) = Rs/ds
height of dish/trough edge = h = r * (a/(2*r))^2 = a^2 / (4*r)
h/a = a/(4*r) = g/4,
Radius or half-width of target = Rt
—-
a/(r – h) = tan(b)
tan(b) = 1/(r/a – h/a) = 1/(1/g – g/4) = 1/G
where G = 1/g – g/4
and
where b is the angle from vertical of the reflected ray from the center of the solar disk, reflected from the edge of the dish/trough.
—-
(relative to both incident and reflected rays from the center of the solar disk, rays from the solar limb will be at an angle q. The reflection of the limb from any point on the reflector will form a circle (in the approximation of the sun as a sphere) on a surface perpendicular to the ray from the disk’s center, but it will be an ellipse on the target surface, with the point farthest from the focus being on the far side of the focus from the point at which the ray was reflected).
—-
q+b is the angle from vertical of the reflected ray from the solar limb that reaches the target surface farthest from the focal point.
C’ = Approximate concentration factor = area of aperture / area of target
C = concentration factor = (area of aperture – area of target)/area of target
Concentration factor for a parabolic trough
C’ = a/Rt
C = C’-1
Concentration factor for a parabolic dish
C’ = (a/Rt)^2
C = C’-1
S = incident direct beam solar flux per unit area (standard full sun (1 atmosphere) is 1000 W/m2, although that may be too large if it includes diffuse radiation)
sigma ~= 5.67e-8 W/(m2*K4)
Teq = (C*S/sigma)^(1/4)
eff = (1 – Tc/Th) * [1 – (sigma * Th^4 / (C*S)]
Brian Dodgesays
“I don´t find your hard core view of scientic concensus very recognizable to working scientists. They usually work in cutting edge areas without concensus.” All that “standing on the shoulders of giants” stuff is just conspiratorial BS to keep the grant money rollin’ in.
CMsays
With apologies to the anarchist comic strip Wildcat: Scientists practice dog-eat-dog consensus, while denialists disagree like zombies.
:)
Andreas Bjurströmsays
379 Richard Ordway,
Again you do not read what I actually say. I hope you can see the big difference between these two statements:
“critical view of the IPCC conservative concensus culture ” (AB)
“disagree with the scientific consensus that we humans are causing global warming (RO).
Please read Scheiders book and you will see that the AB statement is true whereas the RO statement are totally false (I dont think a single quote captures this). Scheider believes strongly in the scientific consensus … and that is probably one of several reasons to his scepticism towards conservative concensus culture. The same is probably true of Jim Hansen for example.
CMsays
Andreas,
The frustration has been mutual. I for one would have liked to learn more about the interesting field you are working on, and your findings might have usefully informed some discussions here. But not the way you’ve been communicating. As long as we’ve known you, you’ve been arguing by ill-phrased assertion. You’ve been telling working scientists how scientists work, then called them ideological for not recognizing themselves in your description, which does not appear to be based on much in the way of field studies. You do not back your claims either with data or references — with the notable exception of your no doubt painstaking analysis of the TAR bibliography, but I don’t think that speaks to many of the points you’ve been arguing. I assume your reference to the comments section here is ironic, and that really you know about representative samples and blog readerships. As for theory, you’ve been telling your critics that they’re not competent to judge what you’re saying because they don’t know the relevant social science literature, and you defend this approach as being merely the reverse of the attitude of the natural scientists here. But many people here go on to actually cite scientific studies, whether to help others learn, or just to show they know what they’re talking about. Do you?
Andreas Bjurströmsays
369 Ray Ladbury,
I think your moral emphasise the collective of the average not that good researchers whereas mine emphasise the brilliant minds that reshape science and cause big breakthroughs. We have a number of such heroic individuals in clmimate change for example. Svante Arrhenius is one of them. Ge liked to be brave and to speculate rather than to restrict himself and nurce the concensus of his time (and he combined this with quantitative data). Today we are glad that he did that. History attend to such minds rather than the cautios minds that nurse concensus.
Andreas Bjurströmsays
386 CM,
I agree with most of your fair critique (as always) but you miss the symmetry (many here act the same as me, some even worse) and the power assymetry (I am one against many) and the purpose of the site (to combat political and scientific climate denialism) and the attitude between “the two cultures” (to overcome this, both sides must contribute with an open attitude) etc. In short, you cant attribute the whole cause of the total breakdown of communication to me.
Ray Ladburysays
Andreas,
Again, I am emphasizing consensus as a standard for RELIABLE approximations of truth. Any single mind, however brilliant, can be wrong. When Newton dominated British science single-handedly, his insistence on a corpuscular theory of light dragged Britain down the wrong path for nearly a hundred years, while Europe dominated optics. On the other hand, although Einstein never accepted the indeterminacy or nonlocality of quantum mechanics, the rest of the physics community continued to progress around him. That is the difference that consensus can make.
Yes, there will be brilliant minds who are well in front of the consensus. However, the competitive nature of science means that every scientist is always on the lookout for new techniques and ideas and theories that will improve his understanding and thereby give him a competitive edge. Scientific consensus advances reliably because
1)scientists are motivated to be early adopters of powerful new ideas and techniques
2)scientists are reluctant to abandon ideas that work for ideas that while intriguing have yet to prove their mettle.
In any case, I contend that requiring a brilliant mind to convince lesser minds like mine of the correctness of her approach is not an insurmountable or unreasonable hurdle. It is like publication–it forces scientists to find improved ways of communicating their ideas and finding applications that demonstrate the usefulness thereof.
Believe it or not, Andreas, I am not hostile to sociological studies of science. My reticence toward much of what passes for scholarship in that field stems from a recognition that the authors have published before they understood the culture they thought to analyze. I have read a plethora of studies that were absolute bullshit attacking science from the political left, the political right, feminist studies, minority studies, sociology, anthropology and even divinity. What all of them had in common was that they did not bother to understand the culture they purported to “deconstruct”.
The problem with most such studies is that they ignore the most notable and important trait of science–the fact that it works astoundingly well in the overwhelming majority of cases and corrects itself on those rare occasions where it does not work well. It is my opinion that until you understand why that is true, you don’t have sufficient understanding of science to say anything meaningful about it. Hint: Scientific consensus plays a huge role in that success.
Completely Fed Upsays
“whereas mine emphasise the brilliant minds that reshape science and cause big breakthroughs”
And then jump to the ASSUMPTION that the IPCC denialists are the ones able to create breakthroughs and deny that the IPCC were the ones who made a breakthrough.
t_p_hamiltonsays
John Peter says:”Global warming predictors that back-casted successfully would be even more impressive to me as a financial analyst…”
Models have back-casted successfully, for the historical record where the temperatures are more precisely known. The low precision in regional paleoclimate is a data problem, not a model problem. That is the reason paleoclimate data may not help much to distinguish between different models. For example – the large uncertainty about the medieval warm period is based on the fact that the northern hemisphere is where most of the land is, and most of the temperature proxies. What we know so far does not indicate warming globally for the medieval period.
The models have also future casted very well (globally), and continue to do so. Large scale effects, such as polar amplification, are quite clear now.
t_p_hamiltonsays
John Peter asks:”If regional models don’t work too well (yet), I have a problem with the “hot here, cold there” explanation we try to use to explain GW. How do we know who’s hot and who’s cold if our models won’t tell us?”
Our thermometers tell us. Weather is chaotic, but climate is the average. The temperature per se is not as much a concern as precipitation patterns, melting ice and rising sea levels (the last two are no-brainer, except for the rate at which we need to adapt).
Rod Bsays
Richard Ordway (353), if you are implying the US Navy is a strong protagonist AGWer, I would suggest that such misleading exaggeration is not helpful to you all.
Rod Bsays
Richard Ordway (360), I might be totally wrong but I think Andreas is mainly saying your consensus is a straw man that you’ve built into an idol.
[Response: If that’s what he’s saying, he’s wrong. There is a very strong consensus on the basics.–Jim]
Completely Fed Upsays
Rod B if you have evidence that Richard’s information is wrong, please present it, rather than smear his post with innuendo.
Ray Ladburysays
No, Rod, rather Richard is suggesting that the Navy is at least reality based.
ge0050says
The idea that long range climate forecasts are more reliable than short term forecasts is fundametally flawed. The simplest example is the coin toss. Over time, you can forecast that the number of heads and tails will balance out. Applying this logic to forecasting, it could be argued that like heads and tails, the errors plus and minus will balance out, and the forecast will become more reliable.
The problem with this is that in the case of climate forecasting, stock market forecasting, currency exchange rate forecasting, inertial guidance systems, and many other “real world” situations, the errors are not heads and tails. The errors are cumulative.
The law of large numbers works for a coin toss because the probability distribution remains the same going forward in time. This does not hold true for systems in which errors are cumulative. The mean may remain unchaned, but the deviation increases. This makes these systems inherently unpredicatble and chaotic.
Looking at chaotic data is like looking at the clouds. It is easy to see pictures of faces or animals – yet we know these are illusions. Like the human mind, pattern recognition software, is also very good at finding patters where no pattern exists.
Climate Modelling is a form of pattern recognition. You train it by looking at the past, trusting that it will predict the future. We are yet to find any modelling software that can predict the stock market long term better than chance. There is no reason to expect climate models will do any better.
[Response: Rather, you have some very fundamentally flawed understandings of predictability in relation to statistics, boundary conditions, and climate modeling. Fortunately, you can address that by reading archived articles here and elsewhere.–Jim]
> John Peter says:
> radiation in equals radiation out. Otherwise we get hotter or cooler.
Yes. It’s called equilibrium, and stays equal in the absence of forcings.
The “Otherwise” you refer to is the climate sensitivity, over a variety of timescales, to changing something that affects that equilibrium.
We burn carbon, fast.
As much carbon burned since 1970 as was burned since civilization started.
Of the CO2 produced at this rate, about half is handled by natural biological cycles and the other half builds up in the atmosphere for a long time.
With the increase in CO2 in the atmosphere, radiation out is delayed, and no longer equals radiation in.
We get hotter.
That’s why we’re talking about this.
Andreas Bjurströmsays
390 Completely Fed Up:
“the IPCC denialists are the ones able to create breakthroughs”
393Rod B says:
25 March 2010 at 9:20 AM
“””Richard Ordway (353), if you are implying the US Navy is a strong protagonist AGWer, I would suggest that such misleading exaggeration is not helpful to you all.””””
____________________________________________________________________
My, my, my, my- that got quite a rise didn’t it?
It is apparently a fact from a direct quote from a US Rear Adm (“For the U.S. Navy, climate change is a challenge — and not a crisis,” said Rear Adm. David Titley, who is leading the Navy’s Task Force Climate Change.”)
…if you want to disprove it, you need to give evidence instead of giving your political opinion. It is what rational people do.
———————————————————————–
‘If true, the US Navy has an active climate change task force:
‘”For the U.S. Navy, climate change is a challenge…” said Rear Adm. David Titley, who is leading the Navy’s Task Force Climate Change.’
Patrick 027
@ 23 March 2010 at 7:23 PM —
Thank you for all the details. Knowing the theoretical targets that limit devices is a wonderful thing. The real questions come in that rich middle ground between physics and engineering (not to mention human factors, which may also be decisive).
Trying to concentrate solar power, for example, is a plausible step, and may be economic. To do it on the real Earth, living in our actual society and economy, you have to make small proofs of concept, then raise enough capital to try it at scale, which is approximately where we are now. The early attempts will understandably be far too expensive, but one hopes to do better with experience and economies of scale.
Let’s say this goes reasonably well, with some investment capital from private or government entities we hope will prove far-sighted. Keep in mind that all the while you are building the wonderful mirrors and towers, or whatever your scheme uses, mostly with fossil fuels. This of course is drawing crucial resources from other crucial projects, like keeping humanity alive and worth living, so the competition is fierce. And you are very proud of your particular scheme, but let’s face it, some of those other dunderheads are wasting those precious, dwindling resources on blind alleys. Perhaps ethanol from corn, or tar sands, are blind alleys, for various reasons. And you have to admit, the mirrors and towers are pretty expensive. (Windmills also concentrate solar power, of course. All the same reasoning applies to them, mutatis mutandis.)
But we aren’t even halfway to the promised land yet. Now that your scheme is showing some hope, start doing it over and over, replicating it worldwide, with less and less fossil fuel, eventually none to speak of. That’s the part nobody knows will work. Counting on being constantly richer (Lomborg’s forehead-slapping error, though he is not alone) is circular reasoning. What if we stop getting richer? We’ve proved previously that we don’t need Peak Oil to get seriously messed up by greed, pyramid schemes, political-economic corruption, and the 4 Horsemen. You have to wonder how all that will feed back when Peak Everything and climate change are thrown in. How will that investment buildup, economic restructuring, and electrification of transportation go in times of decline and war? If you aren’t worried about that, you aren’t thinking.
Also, even if the human factors go better than expected, we lack even a proof of concept showing how much net useful energy can come from renewable technology without using fossil fuels. That’s pretty tough to model. We know at least a little is available, because it’s been done, with wood and dung and muscle built from photosynthesis. We’d like to do better than that. I think you just have to try it. Until we get further down the road, we won’t know where it goes.
This sort of topic can get gloomy. I’m not in favor of dropping dead, and I am in favoring of thinking and caring and doing the best possible with what’s at hand. Assuming that constantly increasing wealth comes from technical knowledge is dangerous. We don’t know what percentage is actually due to fossil fuels.
Oops, if true, it looks like Shell Oil is still trying a type of insidious deception campaign as of March 2010.
http://www.reuters.com/article/idUSLDE62N0ZH20100324?type=marketsNews
[Response: Unbelievable.–Jim]
If true, the US Navy has an active climate change task force:
‘”For the U.S. Navy, climate change is a challenge…” said Rear Adm. David Titley, who is leading the Navy’s Task Force Climate Change.’
http://www.nytimes.com/cwire/2010/03/24/24climatewire-accelerating-arctic-changes-pose-long-term-r-99952.html
BPL, 341 “Some renewables are now cheaper than fossil fuels”.
The figures I found so far agreed more on less on this: 0.05$ per kWh for the oil (at 70$ a barrel) and around 0.3$ per kWh for solar energy. (coal is even a lot cheaper, about 0.01$ per kWh).
So that we have a factor of at least 6.
You are saying that this factor has now been reduced to 1? Are you talking about solar panels? Can you direct me to some studies showing that?
Many thanks
HR@329
Thanks for your interpretation, it’s very interesting to me, I’ll re-read Mike’s initial description and see if I can understand it. In any case thanks again for your contribution to my education. (I’m trying to understand what a “regional model” really is and there seems to be a lot of fairly high powered statistics to crawl through).
I apologize for not being clearer about Mike’s interview. What caught my attention were some questions and answers at the end; the interviewer and Mike were in a fast paced Q&A. To make it easier so there’s no mistake about what Mike said I’ll reproduce it here:
Interviewer – Robert Frederick
Now, as the title of your team’s paper makes note, the time period that you and your team analyzed includes the Little Ice Age and the Medieval Climate Anomaly.
Interviewee – Michael Mann
Right.
Interviewer – Robert Frederick
When are those periods? And, according to your team’s model, what happened?
Interviewee – Michael Mann
So, the complication sometimes in defining those periods is that, unlike the recent warming of the past century, past periods of warming or cooling tend to be very heterogeneous regionally. That means that if one region was relatively warm, there’s a good chance that other regions were cold, and vice-versa. because of that, it means that it’s actually somewhat of a challenge to define, in a global sense, the Little Ice Age or the Medieval Climate Anomaly. What used to be called the “Medieval Warm Period,” most Scientists favor now the use of the term the “Medieval Climate Anomaly” for the reason that I just cited, that it wasn’t warm everywhere, and that’s very clear in our own reconstructions. So, these intervals are a challenge to define because they are so spatially, they’re variable regionally. The warming and cooling happens in different places and different times, but if you look at, say, the average temperature over the Northern Hemisphere, there is a period of somewhere between the 9th century and the 13th century where temperatures were relatively warm compared to subsequent centuries, and, in fact, a period during the, roughly the, say, the 17th century to the 19th century, or somewhere about there, where temperatures averaged over the Northern Hemisphere were relatively cool in comparison with that Medieval Period. But if you look at theMedieval Period, even though it was relatively warm compared to that Little Ice Age, it compares, in a global sense, at most with the level of warming that we saw in the mid-20th century. It doesn’t reach the levels of warmth that we’ve seen in the most recent decades, at least globally. So we used those two intervals characterizing overall when it was relatively cool and relatively mild averaged over the Northern Hemisphere to define the intervals that we would call the Medieval Climate Anomaly and the subsequent Little Ice Age, and then we looked at the spatial patterns of those time intervals.
Interviewer – Robert Frederick
What aspects then, more precisely, of your team’s model of the past may help in predicting current climate change?
Interviewee – Michael Mann
Well, there are really two very interesting observations in the reconstructed patterns that we were actually able to test against climate model predictions. And so, we took those same periods – that Medieval Climate Anomaly period and the Little Ice Age period –and we know, imperfectly, but we have some idea of what the level of natural factors that influenced climate in the past, we sort of know what those factors were. We have a good idea of how the output of the sun has varied over the past thousand years, although there’s some uncertainty. We have a fairly detailed record of the history of explosive volcanic eruptions. And so, these are two natural factors contrasting, for example, with the human factor of increasing greenhouse gas concentrations. These are natural factors that influence climate over time. And we took those factors and we ran two different climate models with the estimated difference in the levels of volcanism and solar output in those two different intervals – in the Medieval Climate Anomaly and the Little Ice Age period. One of the models is the NCAR-coupled model. The other model we used was the NASA Goddard Institute for Space Studies coupled model. So, it gave us sort of a sampling of two different physical representations of the way the climate system responds to these natural factors. And we could look at both of those models, we could see what they predicted, and we could see how it compared with what we actually observed. And what we observed was that the surface temperature patterns during the Medieval era counter intuitive l look more like the La Niña phenomenon, when it’s cold in the eastern and central tropical Pacific. Now, this is a period of time when solar output was relatively high, there was relatively little explosive volcanism, so there was a net heating of the global climate, it was a relatively warm interval, and yet those same factors appear to have drove the climate not into the warm El Niño state of the tropical Pacific, but the cold La Niña state, a bit counterintuitive. We also saw in the reconstructed pattern, that when you compared the Medieval era to the Little Ice Age era, aside from the Medieval era actually being cooler in the tropical Pacific, counter- intuitively what we used to think of the Medieval Warm Period, is that it was actually cold in the tropical Pacific in comparison with the Little Ice Age, which is what we normally think of as the cold period.
Interviewer – Robert Frederick
So, this is the idea of the tropical Pacific acting as a thermostat.
Interviewee – Michael Mann
Absolutely, and we see that in the reconstructions. As it turns out, neither of the two models that we looked at actually exhibit that response.
There are only relatively small subsets of coupled climate models that exhibit this tropical thermostat response; most of the models do the opposite. When you warm the tropical Pacific, the models respond with an El Niño-like state, and when you cool the tropical Pacific, they respond with a La Niña-like state. So the majority of the models used in the most recent IPCC projections, for example, don’t favor the thermostat response – they favor an El Niño-like response to a warming at the surface, like the warming that we’re seeing with increased greenhouse gas concentrations. However, the paleoclimate record of the past thousand years, in our analysis, suggests that at least with respect to the response that the climate has exhibited to natural factors, the response appears to be that thermostat response – it appears to be the opposite of what most of the IPCC projection models project.
Interviewer – Robert Frederick
So is it your team’s intention, then, to try to get your model included in the next assessment of the Intergovernmental Panel on Climate Change, the IPCC?
Interviewee – Michael Mann
Well, the two models…
Interviewer – Robert Frederick
The NCAR and NASA ones are already in there.
Interviewee – Michael Mann
Yeah, exactly. So the – yeah, I think that it’s useful, and in the next IPCC assessment, it may very well be the case that there will be a new section that deals with the question of how paleoclimate data can inform our understanding of some of these fairly complex, dynamical responses of the climate. So, while I don’t see our results as being made explicitly part of an IPCC projection, I do see them as potentially informing our assessment of the extent to which we think the current generation models are, or are not, capturing some of the regional mechanisms that may be important in making regional climate change assessments.
Interviewer – Robert Frederick
Michael Mann, thank you very much.
Interviewee – Michael Mann
Thank you. It was a pleasure talking with you.
This was the time of the climate-gate problems with the MSM; I thought Mike was caught off-guard by the IPCC question but he fielded it very well. He’s one scientist who knows how to talk to the press.
Before your post, I believed I understood this interchange so I posted that understanding. What do you make of it? ;-}
Re Simon Abingdon – signal verse noise:
More generally, a signal is any component of the data’s structure that you are ‘looking for’ and noise is everything else. So what is noise and what is a signal depend on what issue you are studying. A cycle can be a signal. The most basic signal of forced climate change is a longer-term trend, which reflects the change in forcing over time plus a lag-time from thermal inertia, etc. If any noise could occur with long-period trends, than the data alone wouldn’t be enough to pinpoint what the signal is, but considering the physics of the noise (how much low frequency noise could there be?) and using multiple dimensions (spatial-temporal patterns, heat content changes) can help tease things out. However, a change in the texture of the noise itself could constitute a signal of sorts.
Didactylos, I would think that ending comment would more validly be placed at your feet…
345 Richard Ordway,
It seems that you never really listen to what I actually say. The same goes for most people I have discussed with here. And your response is very telling for how politicized climate science is and how that results in a trench warfare with very limited options on how to understand and respond to this very complex and broad problem.
BPL :”BPL: Well, I said I’d stop answering Gilles, but this was too stupid to resist.
They dropped renewables for fossil fuels because fossil fuels were cheaper at the time. Some renewables are now cheaper than fossil fuels, and others are becoming so. And the costs of fossil fuels in terms of pollution and damage to peoples’ health wasn’t properly factored into their costs (and still isn’t).”
BPL : if the situation has changed, we should see that in the marginal capacity added each year. So can you remind me which fraction of the increase of energy (except last year where the energy consumption decreased) is brought by renewable energies in the recent years, compared with fossil fuels ?
358Andreas Bjurström says:
“”””345 Richard Ordway,
It seems that you never really listen to what I actually say…
and I don´t find your hard core view of scientism consensus very recognizable to working scientists. They usually work in cutting edge areas without consensus..””””
This is ripe. Please present some evidence that there is not a scientific consensus from publishing climate scientists whose work holds up over time.
===========================================================================
CONSENSUS
QUOTE: “A plethora of studies from diverse sources indicates a consensus that climate changes will result from mans’ combustion of fossil fuels and changes in land use.”
1979-National Academy of Sciences Archives, “An evaluation of the Evidence for CO2-induced Climate change, Assembly of Mathematical and Physical Sciences, Climate Research Board, Study Group on Carbon Dioxide, 1979, Film label: CO2 and Climate Change: Ad Hoc: General.
Okay dude. I personally have known many of the world’s top publishing climate scientists whose work holds up over time for over 11 years at the climate research center where I was for 11 years as well as NOAA and EPA scientists… and saw many of them and talked to many of them on an almost daily basis.
They accepted the consensus’s for what it was…written solidly in the peer review, but still willing to keep an open mind. Your ideas are mad.
Correction: The formula (1-Tc/Th) * [1 – (Th/Ts)^4] was specifically for dish or other such concentrators that theoretically can focuse sunlight so that at the focus, the flux per unit area would be the same as at the surface of the sun (except for atmospheric effects). It could apply to a parabolic trough concentrator but only if the material at the focus only acted as a blackbody in a limited range of directions… otherwise it might be necessary to … use the square root of Ts in place of Ts (? I haven’t actually done the math yet for that problem).
And all other caveats still apply.
AB (344),
Ray Ladbury has forgotten more about science than you’ve ever known.
Peer review and consensus is how modern science is done, and it has been a fantastically productive system. Everyone I’ve ever encountered who argued against the idea of scientific consensus was a pseudoscientist.
Did (350),
It’s not prejudice just because someone disagrees with you.
I know how a nuclear plant works. I believe a safe nuclear plant can be built. It’s just that I think it would no longer be cost-effective if it were safe. And the damn things take forever to build. Other options are better. If our options were ONLY coal or nuclear, I’d take nuclear. But they aren’t. Period.
Naindj (354),
I’m talking about windmills. And possibly biodiesel; I haven’t seen the latest figures.
Completely Fed Up: No.
Naindj:
BPL and others sometimes fall into overly-simplistic views on energy cost. The reality is that energy costs vary considerably by country, state – even by individual installation. BPL and CFU will try to push the California figures, and pretend that no others exist. I have yet to see figures for California that properly account for subsidies. You seem to be using whole-US figures. In the US, coal is still very cheap.
You can find breakdowns by country and power source here: http://www.ukerc.ac.uk/Downloads/PDF/07/0706_TPA_A_Review_of_Electricity.pdf
I would be very interested if you happen to find any similarly credible sources for global energy costs. I’m not naive enough to claim that the UKERC figures are in any way definitive (but they are the result of academic studies and have no clear bias, unlike most sources of energy cost estimates).
362 Barton Paul Levenson,
Stephen Schneider shows a rather critical view of the IPCC conservative concensus culture (in his new book). Is he a pseudo-scientist according to you?
360 Richard Ordway,
Ýou still don´t read what I actually say. I was mere contesting that a strong culture of concensus are good for scientific progress. To be critical and question the taken for granted are very important in science.
But sure, I can give an example of concensus and climate change. 100 years ago Svante Arrhenius argued that a warmed climate due to AGW is beneficial for humankind. In the cold war era, many climate scientists in the USA was worried of atomic winter. They also worried that aerosols could cause cooling. And they had a technocratic view on the possibility to control climate (keep it stable). The environmental discource where climate is seen as a problem of the environment started in the 1970´s. The concensus we see today stems from this era, and have been gradually produced. We dont know yet, if the concensus frame of today will change in say 10 or 20 years. I would be very surpriced if we dont understand climate differenty in 20 years time.
BPL:
You have made your prejudice about nuclear power very clear in the past. And since those previous discussions, you have already forgotten that different countries have different energy needs, and different renewable resources, and different practical constraints.
Proof, if any were needed, that I am talking to someone who has made up his mind years ago, and who is not open to further discussion.
CND? Chernobyl? Who knows what cemented your opinion. If you honestly believed that “a safe nuclear plant can be built”, then you would not argue against nuclear power using emotive appeals to hysteria, patently false claims about financial viability and frankly ridiculous lists of nuclear fatalities.
Perhaps you could use your list of fatalities to calculate your own estimate of deaths per GWY? Don’t forget to exclude the military accidents.
Andreas says, “Of cource there is a “certain body of knowledge that virtually any researcher in a field must agree upon to be productive”. However, this core body of knowledge change with time.”
Well thank you Dr. Obvious–and you will note that it changed via the efforts or scientists–experts in the field.
Andreas: “Your “concensus is truth” viewpoint can neither explain why scientific knowledge change nor why some important truth can be true one day and false the next.”
Actually, Andreas, first, I never equate consensus with truth. Rather, I state that consensus gives the most reliable approximation of trugh we have at any moment. And my view explains quite precisely why an “important truth” (or rather an approximation thereov) may change. It does so because a new approximate truth does a better job at explaining the phenomena under study. And then to be maximally productive, scientists in that field must adopt that truth–a new consensus emerges.
Moreover, my viewpoint explains why once the explanatory power of a theory becomes sufficiently great, it is very rarely overturned but instead tends to be refined gradually over time. Such gradual evolution is much more common than scientific revolution. It is what we as scientists work at on a daily basis.
Andreas: “If you bothered to pay closer attention to real science, and less to scientific ideology and wishful thinking, you’d know that.”
Actually, Andreas, I not only pay attention to science, I do science. Very applied science, it is true, but it is application of the scientific method. Would you care to name some real scientists who buy into your postmodern [edit]?
BPL@363
Why either/or? Phase the coal out. Phase the nuclear in. Bridge the gaps with solar, wind, biodiesel whatever.
Sounds pretty good to me.
#344 Andreas Bjurstrom, thinking he’s responding to Ray Ladbury #336:
“I am also a real scientist . . .”
Not being a scientists myself, I’ll accept that you are a “real” one. I’ll also humbly suggest that you’ll be a “good” scientist, i.e., contributing to the body of scientific knowledge, when you learn to constrain your highly developed confirmation bias, which has been much in evidence in most of your many postings (generalized, along the lines of “I came to this site and found just what I expected . . .tsk, tsk”). Perhaps you could put it in a blind trust along with your similarly unhelpful, self-described, “warrior” side.
I’m really not interested in encouraging you to post again, so please feel free to consider the following question rhetorical. Where, precisely did Ray L. say that scientific consensus “is truth?”
“But sure, I can give an example of concensus and climate change. 100 years ago Svante Arrhenius argued that a warmed climate due to AGW is beneficial for humankind. In the cold war era, many climate scientists in the USA was worried of atomic winter. They also worried that aerosols could cause cooling. And they had a technocratic view on the possibility to control climate (keep it stable). ”
I dont agree. Since Arrhenius the consensus is that GHG cause warming. At rate of CO2 production in Arrhenius time, the warming might be well be beneficial but I strongly doubt that he would have thought rapid warming was good. The consensus is still that aerosols cause cooling and your only reason for not worrying about an atomic winter is that risk of atomic war has receded. I’ll be very surprised if the consensus here will change in even 10,000 years time.
Soo@331
It seem pretty simple to me. We do the energy balance easily by looking at the earth and sun as black body radiators sitting in space.
The sun radiates mostly IV radiation at the earth. Some gets reflected to space the rest gets absorbed.
The earth radiates IR to space. At the outer edge of the atmosphere these energies must be equal.
The surface temperature of the earth is warmer (35C) than needed to radiate enough energy balance the sun’s. Enough of the energy radiated by the earth is trapped in the atmosphere to reduce the net earth energy to balance with the sun.
To calculate the earth radiation instantaneous emission is averaged diurnally and over latitudes, pole to pole.
If I have this (nearly) right, I can’t envision doing this average “regionally”
> At the outer edge of the atmosphere these energies must be equal.
When? Why? Says who?
t_p_hamilton@335
Thanks for noticing.
If regional models don’t work too well (yet), I have a problem with the “hot here, cold there” explanation we try to use to explain GW. How do we know who’s hot and who’s cold if our models won’t tell us?
As a physicist
“Paleoclimate comparisons might help, they might not.”
makes sense to me, although Mike’s answer is a little better PR.
Global warming predictors that back-casted successfully would be even more impressive to me as a financial analyst…
372 Phil Scadden,
You misunderstand me. I don´t argue about “GHG cause warming” concensus. Climate change is a complex of hundreds of different theories and “hypothesis” and facts and speculations and evaluations …
Im not sure why you cherry-pick just one of the most well-established facts as a symbol for climate change as a whole. To disagree with me you must first understand what I was saying.
Naindj (354): Sorry, but I’ve got to call BS if you’re talking about coal fired electricity going for a cent per KWH.
We are talking about a delivered price for new generation capacity, right? A cent per KWH doesn’t cover the fuel, let alone the plant cost.
Citation required if you’re going to stick with that number.
Someone – Tim Jones, I think, opines:
This isn’t necessarily so. If it takes more energy to extract the oil than the oil provides it won’t be worth doing no matter what the price. If the energy returned is less than the energy invested you have a negative ERoEI.
I wish that were so.
Unfortunately, it’s not always so. It is true if you’re using some of the extracted energy in order to extract more.
With in-situ combustion of coal an tar sands, however, the economics picture is very different than the EROEI picture. How many barrels of would-be oil are burned in place is irrelevant to making a profit. All that counts is money invested and hydrocarbons extracted. Burning 3 barrels in the ground for each barrel extracted means the extraction rate is 25%, but it’s worthwhile if there’s a good financial ROI.
Coal is the same deal. They’re already talking about partially burning it for the producer gas output. Coal to liquid! And you don’t even have to remove the top of the mountain first!!
So, from an greenhouse gas point of view, things could get very ugly when oil starts getting expensive again.
Andreas Bjurström says
“”””Stephen Schneider shows a rather critical view of the IPCC conservative concensus culture (in his new book). Is he a pseudo-scientist according to you?””””
Please give actual quotes from Steve Schneider in your statements. I doubt he or Joe Romm disagree with the scientific consensus that we humans are causing global warming.
________________________________________________________________________
CONSENSUS
1) The USA’s highest science body-1979:
QUOTE: “A plethora of studies from diverse sources indicates a consensus that climate changes will result from mans’ combustion of fossil fuels and changes in land use.”
1979-National Academy of Sciences Archives, “An evaluation of the Evidence for CO2-induced Climate change, Assembly of Mathematical and Physical Sciences, Climate Research Board, Study Group on Carbon Dioxide, 1979, Film label: CO2 and Climate Change: Ad Hoc: General.
_________________________________________________________________________
2) This scientific consensus was repeated by governments of about 120 countries in 1995 in the peer reviewed literature:
QUOTE: “The balance of evidence suggests a discernible human impact on global climate.”
Houghton et al., eds., Climate Change 1995, 5. It’s not hysterical, not catastrophic, …human fingerprint had become scientifically detectible. This was a scientific consensus.
————————————————————————
3) This scientific consensus was repeated in the peer reviewed Science Journal in 2004 by a respected scientist… and the information has held up over time:
QUOTE: “The scientific consensus is clearly expressed in the reports of the Intergovernmental Panel on Climate Change (IPCC)…But there is a scientific consensus on the reality of anthropogenic climate change….In recent years, all major scientific bodies in the United States whose members’ expertise bears directly on the matter have issued similar statements.” Oreskes 2004, Journal of Science.
Study showed that scientists had a consensus that warming would happen since late 1970s…and it did:
_________________________________________________________________________
Why did so many people (nearly ½ Americans) have the impression of a raging debate?
Short answer: That is the impression that a small but powerful group of people, aided and abetted by well-funded think-tanks and a compliant mass media, wanted them to have.
-Peer reviewed Oreskes,- her scholarly book the Merchants of Doubt.
Hank Roberts@374
Hank, you asked:
When? In equilibrium, a day is pretty good, a year would be even better
Why? Conservation of energy. 1st Thermodynamics Law (I think maybe it was Kirkhoff’s absorption=emission?)
http://en.wikipedia.org/wiki/Laws_of_thermodynamics
Who? Probably Stephan or Boltzman. Read Ram’s 0-dimensional model in the 1989 Physics Today Review. Maybe Trenberth around 1997 or any other energy balance description. Out in space radiation in equals radiation out. Otherwise we get hotter or cooler.
Try http://oceanworld.tamu.edu/resources/oceanography-book/radiationbalance.htm
for a more professional description.
Remember we only care about radiation.
Hope this helps 8%)
@ #373 John Peter says: 24 March 2010 at 6:53 PM
John, I’m thinking you are talking about two issues here. One is the overall extent of global warming (net radiation), being induced by an increase in greenhouse gases and all the follow on consequences of that (ice loss etc). The other is the response to global warming in different regions and localities. There is a lot of work going on in regard to both aspects.
The climate models are able to use smaller grids as computing capacity increases and this should help work out regional changes more precisely.
You’ve got me interested in just how the radiation side of things is variously measured and calculated. I’m so far figuring there are various ways of doing it, using data from satellites and ground-based instruments. The new NASA climate site (http://climate.nasa.gov/) is very good and has a lot of information, but it’s not always easy to find exactly what you want :)
Correction for CSP efficiency limits:
The actual limit for concentration of solar radiation (in terms of flux per unit area) is [(distance from center of sun)/(solar radius)]^2 ~= 215^2 ~= 46,300. (I vaguely recall reading that it could be concentrated up to 80,000 times – perhaps this requires some shift in the … I don’t know, it just doesn’t sound right, it would break the second law of thermodynamics; perhaps I misunderstood what the 80,000 specifically measures).
But reaching such a limit for the entirety of the solar flux that is being concentrated may require some nongeometic optics, or at least, something more than a parabolic dish, or a simple lens, so far as I can tell.
Consider for example a parabolic dish, with rays from the center of the solar disk reflecting off the dish precisely onto a focal point. Now what happens to the rays from the limb of the solar disk? If the aperture of the dish is small relative to it’s curvature, then all lines from the focal point to the dish will have nearly the same length, so the rays from the limb of the solar disk reaching different parts of the dish will all make their closest pass to the focal point at about the same distance from the focal point (that distance gets larger for reflected rays from the more distant parts of the dish). And if the aperture is relatively small, the reflected rays from the center of the sun will still be in nearly the same direction, so the rays from the limb will get closest to the focal point while nearly in the plane perpedicular to the axis of the dish (and to the incident solar rays). Thus an approximate image of the sun should be produced on a flat surface at the focal point. However, the small aperture means that the dish covers a small solid angle as seen from this surface; in terms of the flux per unit area, it brings the sun somewhat closer but still far from the theoretical limit.
In order to get to that limit, all points on the target surface would have to ‘see’ the sun in all directions exterior to the target. The dish would have to large enough for the focal point to be within the plane of the dish’s edge, so that radiation reflected off the dish would cover the full hemisphere as seen from all points on the target surface. However, the ‘image’ (if it can be called one?) of the sun produced on this surface by rays reflected from the outer parts of the dish would be larger, and in fact, getting near the edge of the dish, not all reflected sunlight would even reach the surface – near the edge, only about half of the solar rays would reach the target surface at first pass and they would be spread out over an area nearly the size of the aperture of the dish itself (the other rays would be reflected back up after hitting near the edge of the dish on the opposite side of the dish, and they would pass through the target surface mainly near the edge of the dish).
Alternatively, one could have a sphere or ellipsoidal surface at the focus, to better recieve rays from near the edge of the dish. But for a dish of such dimensions that the focus is in the plane of the edge of the dish, the surface recieving radiation from the edge of the dish would only ‘see’ the dish covering about half the ‘field of view’ – the flux per unit area would be half of the theoretical limit; also, in order to capture all solar rays reflected from the dish, the targe would have to extend out to points where reflected rays are only coming from that one part of the dish, thus the flux per unit area would not be so large. The dish can be expanded to increase the concentration; the concentration reaches the theoretical limit when the dish is a full ellipsoid with the other focus at the sun (although a hole in the ellipsoid behind the sun is allowed) – obviously that’s not practical at this point in history, if ever.
Still, the compromises available needn’t fall too far short.
Considering either a parabolic dish or trough, with a flat target surface facing into the dish/trough passing through the focal point/line, just large enough to capture all reflected solar radiation:
—–
With dish aperture radius or trough aperture half-width = a.
distance from center of dish/trough to focal point/line = r.
a/r = g
distance to center of sun = ds
radius of sun = Rs
angle from center of solar disk to limb = q
sin(q) = Rs/ds
height of dish/trough edge = h = r * (a/(2*r))^2 = a^2 / (4*r)
h/a = a/(4*r) = g/4,
Radius or half-width of target = Rt
—-
a/(r – h) = tan(b)
tan(b) = 1/(r/a – h/a) = 1/(1/g – g/4) = 1/G
where G = 1/g – g/4
and
where b is the angle from vertical of the reflected ray from the center of the solar disk, reflected from the edge of the dish/trough.
—-
(relative to both incident and reflected rays from the center of the solar disk, rays from the solar limb will be at an angle q. The reflection of the limb from any point on the reflector will form a circle (in the approximation of the sun as a sphere) on a surface perpendicular to the ray from the disk’s center, but it will be an ellipse on the target surface, with the point farthest from the focus being on the far side of the focus from the point at which the ray was reflected).
—-
q+b is the angle from vertical of the reflected ray from the solar limb that reaches the target surface farthest from the focal point.
(a+Rt)/(r-h) = tan(b+q)
Rt = ([r-h] * tan[b+q]) – a
Rt/a = ([r/a – h/a] * tan[b+q]) – 1
= ([1/g – g/4] * tan[ arcsin(Rs/ds) + arctan( 1 / [1/g – g/4] ) ]) – 1
= (G * tan[ arcsin(Rs/ds) + arctan(1/G) ]) – 1
where G = 1/g – g/4
and g = a/r
—-
C’ = Approximate concentration factor = area of aperture / area of target
C = concentration factor = (area of aperture – area of target)/area of target
Concentration factor for a parabolic trough
C’ = a/Rt
C = C’-1
Concentration factor for a parabolic dish
C’ = (a/Rt)^2
C = C’-1
—-
Theoretical conversion efficiency for blackbody target
= eff
= (1 – Tc/Th) * [1 – (Th/Teq)^4]
where
C*S = sigma * Teq^4
S = incident direct beam solar flux per unit area (standard full sun (1 atmosphere) is 1000 W/m2, although that may be too large if it includes diffuse radiation)
sigma ~= 5.67e-8 W/(m2*K4)
Teq = (C*S/sigma)^(1/4)
eff = (1 – Tc/Th) * [1 – (sigma * Th^4 / (C*S)]
“I don´t find your hard core view of scientic concensus very recognizable to working scientists. They usually work in cutting edge areas without concensus.” All that “standing on the shoulders of giants” stuff is just conspiratorial BS to keep the grant money rollin’ in.
With apologies to the anarchist comic strip Wildcat: Scientists practice dog-eat-dog consensus, while denialists disagree like zombies.
:)
379 Richard Ordway,
Again you do not read what I actually say. I hope you can see the big difference between these two statements:
“critical view of the IPCC conservative concensus culture ” (AB)
“disagree with the scientific consensus that we humans are causing global warming (RO).
Please read Scheiders book and you will see that the AB statement is true whereas the RO statement are totally false (I dont think a single quote captures this). Scheider believes strongly in the scientific consensus … and that is probably one of several reasons to his scepticism towards conservative concensus culture. The same is probably true of Jim Hansen for example.
Andreas,
The frustration has been mutual. I for one would have liked to learn more about the interesting field you are working on, and your findings might have usefully informed some discussions here. But not the way you’ve been communicating. As long as we’ve known you, you’ve been arguing by ill-phrased assertion. You’ve been telling working scientists how scientists work, then called them ideological for not recognizing themselves in your description, which does not appear to be based on much in the way of field studies. You do not back your claims either with data or references — with the notable exception of your no doubt painstaking analysis of the TAR bibliography, but I don’t think that speaks to many of the points you’ve been arguing. I assume your reference to the comments section here is ironic, and that really you know about representative samples and blog readerships. As for theory, you’ve been telling your critics that they’re not competent to judge what you’re saying because they don’t know the relevant social science literature, and you defend this approach as being merely the reverse of the attitude of the natural scientists here. But many people here go on to actually cite scientific studies, whether to help others learn, or just to show they know what they’re talking about. Do you?
369 Ray Ladbury,
I think your moral emphasise the collective of the average not that good researchers whereas mine emphasise the brilliant minds that reshape science and cause big breakthroughs. We have a number of such heroic individuals in clmimate change for example. Svante Arrhenius is one of them. Ge liked to be brave and to speculate rather than to restrict himself and nurce the concensus of his time (and he combined this with quantitative data). Today we are glad that he did that. History attend to such minds rather than the cautios minds that nurse concensus.
386 CM,
I agree with most of your fair critique (as always) but you miss the symmetry (many here act the same as me, some even worse) and the power assymetry (I am one against many) and the purpose of the site (to combat political and scientific climate denialism) and the attitude between “the two cultures” (to overcome this, both sides must contribute with an open attitude) etc. In short, you cant attribute the whole cause of the total breakdown of communication to me.
Andreas,
Again, I am emphasizing consensus as a standard for RELIABLE approximations of truth. Any single mind, however brilliant, can be wrong. When Newton dominated British science single-handedly, his insistence on a corpuscular theory of light dragged Britain down the wrong path for nearly a hundred years, while Europe dominated optics. On the other hand, although Einstein never accepted the indeterminacy or nonlocality of quantum mechanics, the rest of the physics community continued to progress around him. That is the difference that consensus can make.
Yes, there will be brilliant minds who are well in front of the consensus. However, the competitive nature of science means that every scientist is always on the lookout for new techniques and ideas and theories that will improve his understanding and thereby give him a competitive edge. Scientific consensus advances reliably because
1)scientists are motivated to be early adopters of powerful new ideas and techniques
2)scientists are reluctant to abandon ideas that work for ideas that while intriguing have yet to prove their mettle.
In any case, I contend that requiring a brilliant mind to convince lesser minds like mine of the correctness of her approach is not an insurmountable or unreasonable hurdle. It is like publication–it forces scientists to find improved ways of communicating their ideas and finding applications that demonstrate the usefulness thereof.
Believe it or not, Andreas, I am not hostile to sociological studies of science. My reticence toward much of what passes for scholarship in that field stems from a recognition that the authors have published before they understood the culture they thought to analyze. I have read a plethora of studies that were absolute bullshit attacking science from the political left, the political right, feminist studies, minority studies, sociology, anthropology and even divinity. What all of them had in common was that they did not bother to understand the culture they purported to “deconstruct”.
The problem with most such studies is that they ignore the most notable and important trait of science–the fact that it works astoundingly well in the overwhelming majority of cases and corrects itself on those rare occasions where it does not work well. It is my opinion that until you understand why that is true, you don’t have sufficient understanding of science to say anything meaningful about it. Hint: Scientific consensus plays a huge role in that success.
“whereas mine emphasise the brilliant minds that reshape science and cause big breakthroughs”
And then jump to the ASSUMPTION that the IPCC denialists are the ones able to create breakthroughs and deny that the IPCC were the ones who made a breakthrough.
John Peter says:”Global warming predictors that back-casted successfully would be even more impressive to me as a financial analyst…”
Models have back-casted successfully, for the historical record where the temperatures are more precisely known. The low precision in regional paleoclimate is a data problem, not a model problem. That is the reason paleoclimate data may not help much to distinguish between different models. For example – the large uncertainty about the medieval warm period is based on the fact that the northern hemisphere is where most of the land is, and most of the temperature proxies. What we know so far does not indicate warming globally for the medieval period.
The models have also future casted very well (globally), and continue to do so. Large scale effects, such as polar amplification, are quite clear now.
John Peter asks:”If regional models don’t work too well (yet), I have a problem with the “hot here, cold there” explanation we try to use to explain GW. How do we know who’s hot and who’s cold if our models won’t tell us?”
Our thermometers tell us. Weather is chaotic, but climate is the average. The temperature per se is not as much a concern as precipitation patterns, melting ice and rising sea levels (the last two are no-brainer, except for the rate at which we need to adapt).
Richard Ordway (353), if you are implying the US Navy is a strong protagonist AGWer, I would suggest that such misleading exaggeration is not helpful to you all.
Richard Ordway (360), I might be totally wrong but I think Andreas is mainly saying your consensus is a straw man that you’ve built into an idol.
[Response: If that’s what he’s saying, he’s wrong. There is a very strong consensus on the basics.–Jim]
Rod B if you have evidence that Richard’s information is wrong, please present it, rather than smear his post with innuendo.
No, Rod, rather Richard is suggesting that the Navy is at least reality based.
The idea that long range climate forecasts are more reliable than short term forecasts is fundametally flawed. The simplest example is the coin toss. Over time, you can forecast that the number of heads and tails will balance out. Applying this logic to forecasting, it could be argued that like heads and tails, the errors plus and minus will balance out, and the forecast will become more reliable.
The problem with this is that in the case of climate forecasting, stock market forecasting, currency exchange rate forecasting, inertial guidance systems, and many other “real world” situations, the errors are not heads and tails. The errors are cumulative.
The law of large numbers works for a coin toss because the probability distribution remains the same going forward in time. This does not hold true for systems in which errors are cumulative. The mean may remain unchaned, but the deviation increases. This makes these systems inherently unpredicatble and chaotic.
Looking at chaotic data is like looking at the clouds. It is easy to see pictures of faces or animals – yet we know these are illusions. Like the human mind, pattern recognition software, is also very good at finding patters where no pattern exists.
Climate Modelling is a form of pattern recognition. You train it by looking at the past, trusting that it will predict the future. We are yet to find any modelling software that can predict the stock market long term better than chance. There is no reason to expect climate models will do any better.
[Response: Rather, you have some very fundamentally flawed understandings of predictability in relation to statistics, boundary conditions, and climate modeling. Fortunately, you can address that by reading archived articles here and elsewhere.–Jim]
> John Peter says:
> radiation in equals radiation out. Otherwise we get hotter or cooler.
Yes. It’s called equilibrium, and stays equal in the absence of forcings.
The “Otherwise” you refer to is the climate sensitivity, over a variety of timescales, to changing something that affects that equilibrium.
We burn carbon, fast.
As much carbon burned since 1970 as was burned since civilization started.
Of the CO2 produced at this rate, about half is handled by natural biological cycles and the other half builds up in the atmosphere for a long time.
With the increase in CO2 in the atmosphere, radiation out is delayed, and no longer equals radiation in.
We get hotter.
That’s why we’re talking about this.
390 Completely Fed Up:
“the IPCC denialists are the ones able to create breakthroughs”
In your dreams perhaps ;-)
393Rod B says:
25 March 2010 at 9:20 AM
“””Richard Ordway (353), if you are implying the US Navy is a strong protagonist AGWer, I would suggest that such misleading exaggeration is not helpful to you all.””””
____________________________________________________________________
My, my, my, my- that got quite a rise didn’t it?
It is apparently a fact from a direct quote from a US Rear Adm (“For the U.S. Navy, climate change is a challenge — and not a crisis,” said Rear Adm. David Titley, who is leading the Navy’s Task Force Climate Change.”)
…if you want to disprove it, you need to give evidence instead of giving your political opinion. It is what rational people do.
———————————————————————–
‘If true, the US Navy has an active climate change task force:
‘”For the U.S. Navy, climate change is a challenge…” said Rear Adm. David Titley, who is leading the Navy’s Task Force Climate Change.’
http://www.nytimes.com/cwire/2010/03/24/24climatewire-accelerating-arctic-changes-pose-long-term-r-99952.html ‘