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Comments 90801 to 90850:
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Peter Hogarth at 10:17 AM on 27 March 2011A Plan for 100% Energy from Wind, Water, and Solar by 2050
adelady at 08:39 AM on 27 March, 2011 It's only less than a century since the last of the great steel hulled cargo carrying four masted barques were still running commercially. The massive shift to fossil fuel powered vessels took only a generation (a positive lesson) but the transition also took more than will, technology, and imagination, it was a question of raw economics. Unfortunately, now as then, few people look to return on investment over timescales of even a single generation, and as Danas summary suggests, the competitive psychology of the free market is seen as a real barrier. Time to read the study. -
L.J. Ryan at 10:08 AM on 27 March 20112nd law of thermodynamics contradicts greenhouse theory
KR Q2) What is the LW radiation emissivity of the earths surface? Note: I'm not asking about the effective surface to space emissivity but rather the surface emissivity. -
Rob Honeycutt at 10:08 AM on 27 March 2011Models are unreliable
Eric... But how could you possibly rationalize sensitivity that low? The only papers that make such a claim (Lindzen 2009) have been shown to be questionable, and are not supported by paleoclimate estimations. -
Stu at 09:45 AM on 27 March 2011Models are unreliable
Eric, "To specifically answer Rob (#313) the model I would propose is a low sensitivity, short time lag model in which CO2 and natural forcing creates about 1.2C sensitivity (defined as temperature change for a doubling of CO2 or 3.7W/m2" The sensitivity of a model is an emergent property, not pre-programmed. That's why one function of models is to estimate sensitivity. You could certainly tweak a model to produce a high or low sensitivity, but the ultimate goal should be to make a model that reproduces the entire climate system as realistically as possible, and then see what sensitivity it has... -
michael sweet at 09:40 AM on 27 March 2011A Plan for 100% Energy from Wind, Water, and Solar by 2050
Dana: This is a terrific post. It is good to show what the options are. I notice that everyone lives the same standard of life that we have today, or better! And it is cheaper in the end! This counters the skeptic argument that without Fossil Fuels we all have to go live in caves. Don: That is the saddest question. -
adelady at 08:39 AM on 27 March 2011A Plan for 100% Energy from Wind, Water, and Solar by 2050
Peter Hogarth. Sail for cargo vessels? Not very likely - but kites could very easily develop to help the proposed "hybrid hydrogen fuelcell-battery systems" the authors are keen on for shipping. -
Albatross at 08:38 AM on 27 March 2011Of Satellites and Air – A Primer on Tropospheric temperature measurement by Satellite
Peter @14, Thanks for that great link-- super resource. -
RobertS at 08:31 AM on 27 March 2011The Libertarian Climate Conundrum
From Peru, "Americans are funny. "Libertarianism" elsewere is a branch of COMMUNISM ("Libertarian Communism", a.k.a. Anarchism). How the far right hijacked a term associated with the fartest extremes of the socialist left is still a mistery to me." Yes, political labels evolve. This is no revelation. Both "liberal" and "conservative" also had very different meanings historically than they do in modern American politics. They still do have different meanings in other parts of the world. "Libertarian" was co-opted by the right in the early 20th century to distinguish themselves from the statists that co-opted the term "liberal". -
Daniel Bailey at 08:29 AM on 27 March 2011Temp record is unreliable
Keep in mind, Chris, that Fig D you refer to is only for the United States and is based on running 5-year means. In English, this translates to the info shown for the last 5 years on the graph is less certain and more variable (relative to that which preceded it). The Yooper -
les at 07:44 AM on 27 March 2011Temp record is unreliable
146 sjshaker Ask you self this. If you had seen that graph in the early 1990s - obviously only with the numbers up to then - would you not say the same thing? Would you have been right? Given which, do you think looking at the ups and downs over a time range of a couple of years is reliable? -
johnd at 07:41 AM on 27 March 2011Weather vs Climate
actually thoughtfull at 06:49 AM, your comment about terrible weather predictions in your area is quite telling. Firstly you probably accept it because it might only impact on whether your take an umbrella or not and so the free, but entertaining forecast attached to the TV news remains useful in providing a topic of conversation, and an excuse to complain. But for those whose businesses and enterprises depends on accurate short and long range forecasts, that is not only not good enough, but totally unacceptable. So what do they do? They seek out services that have proven track records and provide real value for money. Free is hardly ever free. So one of the points that your comment raises is, whilst, as you noted, there are weather forecasters out there that are virtually useless, but probably still retain a large and faithful following, and whilst there are also probably unknown to yourself, weather modelers, that by virtue of providing reliable and useful projections for more astute investors, and are able to charge high fees for their services, is it possible that the same range of expertise might also be within the ranks of those who model climate? Just for interest:- (1)How many people who read this thread are totally dependent on accurate forecasts for planning the next year or two forward? (2)How many people are totally dependent on accurate forecasts to make decisions about umbrellas? -
cjshaker at 07:39 AM on 27 March 2011Temp record is unreliable
At NASA's GISS Surface Temperature Analysis webpage http://data.giss.nasa.gov/gistemp/graphs/ The Annual Mean Temperature Change in the United States appears to have peaked and is dropping at the end of the graph? http://data.giss.nasa.gov/gistemp/graphs/Fig.D.gif -
From Peru at 07:29 AM on 27 March 2011The Libertarian Climate Conundrum
Americans are funny. "Libertarianism" elsewere is a branch of COMMUNISM ("Libertarian Communism", a.k.a. Anarchism). How the far right hijacked a term associated with the fartest extremes of the socialist left is still a mistery to me. So far, Obama has not done a good work, but not because did an intervention in the economy, but but because that intervention was too LITTLE by far! He should have wiped out all the Las-Vegas-Casinos like crowd out of the banking system, nationalizing the whole finacial system and put the speculators that destroyed the US and Europe economy (thanks to the non-regulation of Mr. George Bush) on trial, demanding they to PAY for all the damage they done. On the climate front, the nationalization of General Motors and intervention in Chrisler should have been used to make an U-turn and make a series of 4-Year Plans for the Auto Industry to improve efficiency and switch to hybrids and electric vehicles, and shutting down the production of SUVs and similar monsters. The plans should have been strictly enforced by the government adiministration (after all, if you buy a company, you should administate it, or not?) But instead Obama choose to make enormous bailouts to the bankrupt financial-industrial complex while leaving the same people that lead the nation to disaster still in office, continuing to do the same irresponsible speculation that caused the crisis in the first place. Obama lost the opportunity to change the terminally ill economy of the USA. The people that caused the crisis are still there, and the bailouts that avoided a second Great Depression also saved the anti-people crowd (the financial speculators) from self-destruction. Some people dislike regulation. Maybe they like poisoned river streams, breath choking smoke, food and oil prices skyrocketing, and banks taking the homes of the people ... Regulations would have prevented the 2007-2011 crisis. Now, without a massive government intervention in the economy, the seeds are still there for a second economic collapse. -
cjshaker at 07:18 AM on 27 March 2011We're heading into an ice age
Here is another way of finding the temperature delta over the 100,000 year glacial cycle, from measuring the concentrations of atmospheric noble gases dissolved in groundwater. He came up with a delta T of 8.8 C, which is fairly close to what we see on the graph of proxy temperatures derived from the ice cores http://www.ldeo.columbia.edu/~etg/werner/maryland/MD.Abstract.html -
actually thoughtful at 07:11 AM on 27 March 2011A Plan for 100% Energy from Wind, Water, and Solar by 2050
Dana1981 - it is true that a heat pump run from renewable electricity sources is a great way to solve the issue of heat (and even more elegantly - build an envelope that doesn't need to be heated/cooled), and that is the reason for the paradoxical argument that using more electricity is better. But solar thermal for heat is an important technology that takes a notable portion of the load off of electricity and puts it in locally managed systems. It is also currently 4-5 times more efficient than making electricity from renewable resources. It is often overlooked because it isn't drop dead simple like plugging in some PV panels (with respect to the PV installers out there). And while we must stay focused on the future, and ending carbon emissions, we also have to stay in touch with reality, and the reality is that switching from gas to coal-fired electricity for a heat pump is a net INCREASE in carbon emissions. Sure, eventually (bounded by the end of fossil fuels) it will be powered by renewables. But even the study you are high-lighting for us doesn't see even new power coming from renewables (only) until 2030 - there is low hanging fruit here to switch to solar thermal for process heat, space heating, and even space cooling (absorption chiller run by a high temp solar thermal collector system (high temp being 180F-212F)). Solar thermal is the easy "S" of WWS, and meets all the requirements of the study's authors. I myself was very surprised to learn that carbon emission went up with the use of a ground source heat pump (using national average mix of fuels to create the electricity). It does sound good on paper, as it is much more efficient than compressor-cooling, which is done almost entirely with electricity. And it just makes sense to use the same great technology for heat (this is where it fails). Solar heating will be the more efficient method for the foreseeable future. And of course if you live in the desert southwest, you can create your cooling through evaporation, so long as we have water. If you accept that we are using more electricity than we can currently produce via renewables (and this will be the case for a while), and you understand that solar thermal has a (small to medium) per BTU edge over renewable methods of creating electricity (including wind) - then it just follows that you create heat from solar thermal first, then create heat from other methods (waste industrial, geothermal, wind, solar thermal (concentrating), wave, PV (probably in that order)). -
Don Gisselbeck at 07:02 AM on 27 March 2011A Plan for 100% Energy from Wind, Water, and Solar by 2050
What would have happened if hypothetically moral and intelligent leaders after 9/11 had invested a trillion dollars or so into renewable energy instead of wasting money on stupid wars? -
dana1981 at 06:51 AM on 27 March 2011A Plan for 100% Energy from Wind, Water, and Solar by 2050
actually thoughtfull - regarding heat pump carbon emissions, I suppose a key to this plan is that we're also transitioning toward renewables in the power grid at the same time we're increasing the use of heat pumps. -
actually thoughtful at 06:49 AM on 27 March 2011Weather vs Climate
Two comments: one, where I live, weather predictions are still terrible. I think the "Can't predict weather...can't predict climate" argument is based in enough reality ("Can't predict weather") that it really, truly needs to be addressed. I do think it was well addressed here. As to Poptech and Ken Lambart and a few other posters. I hope smart, knowledgeable people will continue to refute the ideas they present when they are wrong. I personally don't have any problem seeing that models work (Hansen 1988 is still mind boggling to me - 23 years ago he knew what would happen to us right now!). But the claims that Trenberth's travesty is still with us will give me pause until we can irrefutably (within reason) put it to bed. Perhaps others are the opposite - they understand the limitation of ARGO, have read the studies regarding deep ocean temperatures (and a few lakes which give us fascinating insights into ocean heat content and heat transfer behavior) and see no problem with the supposedly missing heat. It is for those readers (presumably many X larger than those of us who post - else this is a lot of work for very few eyeballs...) that honest refutations of misinformation (regardless of the sincerity of the poster - wrong is wrong) are so valuable. Perhaps the moderators have to be even more hard nosed to move the debate to the right thread? That would ensure that those of us taken in by the false claim would read the background/supporting post and hopefully get a better understanding, so as not to be taken in by the same claim next time. -
johnd at 06:49 AM on 27 March 2011Weather vs Climate
Here is a paper that could be posted in various different threads as it has relevance to a number of topical subjects such as weather/climate modeling, modeling reliability, SST. Read and enjoy/learn/weep as so inclined. Impact of Global Ocean Surface Warming on Seasonal-to-Interannual Climate Prediction -
Eric (skeptic) at 06:47 AM on 27 March 2011Models are unreliable
i didn't find "Schwartz" in a cursory search of this thread. It is two of the entries on PT's list (the 2007 paper plus the 2008 response). In the 2007 rebuttal by Foster et al, http://www.jamstec.go.jp/frsgc/research/d5/jdannan/comment_on_schwartz.pdf the climate system time lag was claimed to be irreducibly complex: "Such a multicomponent physical system cannot be expected to act with a single time scale. Even if the system evolves according to an AR(1) process, it must be a vector AR(1) process with many distinct time scales" They criticize Schwartz's short time constant by a inference to the long time constant of the deep ocean. But there is no set of independent variables on which to perform a vector AR1, all of the other temperature variables (deep ocean, mixed ocean, cryosphere) are functions of global average surface temperature. Schwartz is correct in his rebuttal http://www.ecd.bnl.gov/pubs/BNL-80226-2008-JA.pdf that the time constants in the models can be reduced to a single time constant which can be estimated using AR1. The critics (Foster, Annan, Schmidt and Mann) conditionally accept the AR1 premise, then work backwards from their models with high climate sensitivity to prove that the time AR1 time constant can't be as short as Schwartz claims. But that's really putting the cart before the horse. To specifically answer Rob (#313) the model I would propose is a low sensitivity, short time lag model in which CO2 and natural forcing creates about 1.2C sensitivity (defined as temperature change for a doubling of CO2 or 3.7W/m2) -
muoncounter at 06:31 AM on 27 March 2011A Plan for 100% Energy from Wind, Water, and Solar by 2050
Jacobson's prior work on the adverse health effects of urban CO2 domes make this plan that much more urgent. Jacobson's study is the first to look at the health impacts of carbon dioxide domes over cities and his results are relevant to future air pollution regulations. Current regulations do not address the local impacts of local carbon dioxide emissions. ... "There has been no control of carbon dioxide because it has always been thought that CO2 is a global problem, that it is only its global impacts that might feed back to air pollution," Jacobson said. -
Alexandre at 06:22 AM on 27 March 2011A Plan for 100% Energy from Wind, Water, and Solar by 2050
Great series of posts about these comprehensive studies on the transition to renewables. Thanks and keep it coming. -
actually thoughtful at 06:09 AM on 27 March 2011A Plan for 100% Energy from Wind, Water, and Solar by 2050
Good news: most of these studies greatly under-predict what can be done with solar thermal space heating. The industry "wisdom" is that you can get 40-50% with solar thermal. I have installed space heating systems in a dozen homes that are much closer to 75%. And with smarter controls, I believe I can get north of 80%. So various combinations of solar thermal and ground source heat pumps work everywhere. A caution with heat pumps - they reduce heating costs by ~50% - but they don't reduce carbon emissions with the current mix of fuels to create electricity. Given the multi-decade struggle we are in to ramp up electricity production from electricity, it is a very good move, in a significant space heating climate, to use solar thermal to minimize the load and use a heat pump, or even burning natural gas, as the final backup. That is much preferable to adding additional load to the electric grid, which is currently coal dominated, and in the future will always be hard pressed to get enough renewable sources on line. Don't add to that load with space heating. {Also note that a window upgrade (to R-5 or higher) increases comfort and decreases energy required to heat/cool the house. -
Stu at 06:04 AM on 27 March 2011Models are unreliable
In reply to Poptech: "...my point [is that] if your initial conditions are uncertain that makes the results uncertain. Uncertain is a damn sight removed from worthless, don't you think? I said: "In climate models, if you are expecting them to perfectly model the exact evolution of the atmosphere, then you are essentially expecting them to be a perpetual weather model." You said: "That is exactly my point. If they cannot do this, their results are meaningless. Calling computer code a "climate model" does not change how computers work." So we've gone from uncertain to meaningless? Well, weather models also can't perfectly model the evolution of the atmosphere. Are their results meaningless? If you have ever taken an unbrella with you because the weatherman said it would rain, there's a good chance you did it on guidance that you yourself consider 'meaningless'. I said: "Additionally, to be 'perfect', a climate model would need both perfect initial knowledge of the entire ocean, cryosphere and biosphere, and perfect knowledge of the future evolution of all things that affect climate: solar output, GHGs, aerosols, volcanoes, etc etc etc. And what's more, the 'perfect' model is a pipe dream because models treat continuous time and space as finite blocks." You said: "Exactly, which is why computer climate models for predictions are worthless." Climate models are supposed to estimate the avolution of the climate for a given scenario. One thing they aren't is a deterministic forecast. They provide a projection, not a prediction. That's not just a matter of semantics, there is a distinct difference in meaning. Oh, and as you agreed with me in all of the above except interpretation, you have some hubris to claim that: "Stu you display ignorance of computer systems and computer science." - care to point out where? -
2nd law of thermodynamics contradicts greenhouse theory
L.J. Ryan - I did answer your question: 240 W/m^2 incoming flux is expected to, and does, generate a temperature of about 287K in the Earth climate system. How was I not clear about that? "Q1) What is the SW radiation emissivity of the earths surface": Irrelevant question - it's zero. The Earth is not at a temperature to glow in visible light. The Earth effective absorptivity, on the other hand, is about 70-75% for the solar spectrum. The band-limited input energy that doesn't overlap with the output IR is why input power is essentially fixed. -
L.J. Ryan at 05:47 AM on 27 March 20112nd law of thermodynamics contradicts greenhouse theory
KR 854 You've skipped the SW absorption step. Since you seem to be avoiding my question---Ok, "incoming energy is essentially fixed" i.e. ~240W/m^2, so what temperature should be generated via this, and only this flux?---lets try it this way. Q1)What is the SW radiation emissivity of the earths surface? -
Peter Hogarth at 05:36 AM on 27 March 2011A Plan for 100% Energy from Wind, Water, and Solar by 2050
Thanks Dana. As we look forwards, here's a nostalgic thought. I haven't even thought about the numbers, but the economics of large sail powered (or at least assisted) cargo vessels might be viable and the technology well proven? Now that we have satellite technology to plot the best course to catch the optimum winds... -
2nd law of thermodynamics contradicts greenhouse theory
DB - Thanks, that's where I was trying to point; I was trying to (A) refer to that graph (yes, that's the one) and to (B) make a point that this information been presented since the beginning of this thread. Sorry about the poor typing/tags; there may be more caffeine in my immediate future. -
2nd law of thermodynamics contradicts greenhouse theory
L.J. Ryan - That link to #27 was intended to be the chart; sorry if I was unclear. Given a power to be radiated of 240W/m^2, the Stefan-Boltzmann relationship of Power=emissivity*Area*σ*T^4, where σ is the SB constant, and the [observed, measured!] effective emissivity from ground to space of ~0.612, I expect the surface temperature to be about 287K. A black body could emit 240W/m^2 at a much lower temperature. But: if radiated power remains fixed (by the 1st law of thermodynamics, conservation of energy), any gray body object (or planet) with a lower emissivity must necessarily have a higher temperature than a black body to radiate that power level. Which is the point I have been trying to make for the last several posts. -
les at 05:32 AM on 27 March 2011One of the best climate change ads I've seen
33 superfreak - "truthiness" From here “truthiness” — the Word of the Year in 2005, according to the American Dialect Society, which defined it as “the quality of preferring concepts or facts one wishes to be true, rather than concepts or facts known to be true.” Well, yes I guess if you post up truthiness it may not get you very far... but go for some cold hard facts or detailed analysis and it'll probably be fine. -
RobertS at 05:14 AM on 27 March 2011The Libertarian Climate Conundrum
Muoncounter, May I suggest that, if you're making a political argument, you do so in a separate comment rather than under the guise of "moderator". It tends to make it seem less like you're arguing for the site as a whole. Just a suggestion. Overall, though, I agree with Scaddenp. -
Peter Hogarth at 04:52 AM on 27 March 2011Models are unreliable
Perhaps time to revisit Hansens model updated with observed data up to Feb 2011, putting six more years worth of real data onto the chart in the intermediate version of this post:
I’ll offer few comments other than the obvious but easily and often missed point that observed average global temperatures have in fact gone up since 1988, and that they have not levelled off, and they certainly aren’t going down. Limitations of this particular model have been discussed elsewhere (it slightly over-predicted CO2 levels). A massive amount of work has been done since. Hansen had many critics at the time.
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L.J. Ryan at 04:43 AM on 27 March 20112nd law of thermodynamics contradicts greenhouse theory
KR 852 "To echo your posting - Do you agree?" somewhat Ok, "incoming energy is essentially fixed" i.e. ~240W/m^2, so what temperature should be generated via this, and only this flux. your hyperlink #27 goes nowhere..or is it the included chartModerator Response: [DB] See above. -
Albatross at 04:26 AM on 27 March 2011Weather vs Climate
Moderators, why is Poptech being permitted to troll and derail this thread? I agree with Rob @60, SkepticalScience is above this kind of nonsense and typically has a very high signal-to-noise ratio, that is why it is pretty much the only place that I choose to post on climate issues. -
Rob Honeycutt at 04:01 AM on 27 March 2011Weather vs Climate
flambeaub.... I know it seems futile at times but I think it is a valuable exercise debating Poptech. I always try to put myself in the shoes of the broader readership here. What are they seeing in the conversation? I believe they easily see through PT's distortions and they see the other commenters here being mostly reasonable in their responses to him. People easily see the extremes PT goes to to defend his position. In that I believe the debate with him helps people to understand the larger debate on climate is almost exactly the same. On top of that, it's a bit of a car crash every time PT stops by. And like a car crash it's hard for people NOT to watch. It appeals to our more base level instincts. I don't think anyone wants to see Skeptical Science become just about this kind of car crash. Many may disagree with this but overall, from time to time, a PT car crash serves it's purposes. -
MichaelM at 03:55 AM on 27 March 2011Weather vs Climate
Poptech et al provide great examples of the other side. They show off the arguments they have so badly that it is almost reassuring and at times comical. -
flambeaub at 03:30 AM on 27 March 2011Weather vs Climate
I just started reading this blog a few days ago and find the information useful and more up to date than I can find anywhere else. However, I must say that I find it strange that Poptech seems to have hijacked this discussion and intelligent people are spending lots of time rebutting the same stupid arguments and he is not listening. Is this really the best use of our time and energy? -
2nd law of thermodynamics contradicts greenhouse theory
L.J. Ryan I'll reply to those points out of order, first noting that you keep stating "240 W/m^2 emitted at 255K" without the very important black body included. Q3 - "By "thermal spectra" do you mean "atmospheric forcing"?" No. I mean the thermal emission spectra of the objects in question. The Sun's and Earth's thermal emission spectra are not identical (#27), and in fact barely overlap. Hence what affects one region (visible, IR, etc.) may or may not affect others.
Q1 - "..so solar input to the earth SURFACE of 240 W/m^2 equates to~255K." Inexact and misleading.
The sun provides ~240 W/m^2 via the 70-75% of solar emissive spectra that makes it through to the surface. This amount is at different wavelengths than the Earth thermal emission. And while 240 W/m^2 may be the energy emitted by a black body at 255K, neither solar input or Earth output is an unfiltered black body curve.
Q1 - Nonsense. 255K represents the maximum black body temperature, but since solar input is mostly unaffected by GHG's (except for WV/clouds, but the sum effect appears to decrease emission relative to absorption, increasing forcing) - incoming energy is essentially fixed.
And in order to radiate 240W/m^2, a temperature of 255K is an absolute minimum temperature for a gray body such as the Earth, as decreasing emissivity reduces power emitted at any particular temperature.
To echo your posting - Do you agree?
Moderator Response:[mc] fixed unclosed bold tag
[DB] KR, I think I guessed correctly as to which comment you were linking to & also included the Figure it seemed likely you had in mind. If I'm wrong, let me know & how to fix it & I will.
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Rob Honeycutt at 03:11 AM on 27 March 2011Models are unreliable
What gets me about this issue is the "skeptics" only use it as a way to instill doubt about climate change. They offer no alternate solution. No one claims that models can perfectly predict future climate but they can give us very important perspective on what we are doing to the climate. Does anyone expect that any specific area on the planet will change exactly the way models show? No. But we get strong indications of what ways the planet is going to change. Enough of an indicator to seriously look for ways to deal with the problem. If the "skeptics" were serious about this issue they'd offer up something better. How would they propose to test changes in the climate system? Modelers are doing what is necessary to test conditions. If "skeptics" think they're getting it wrong somehow then they need to produce their own models instead of just playing the doubt game. -
actually thoughtful at 02:58 AM on 27 March 2011A Plan for 100% Renewable Energy by 2050
Gilles - your analysis assumes man is strictly logical in his actions - therefore utilize every available "cheap" unit of FF. But your analysis ALSO assumes man is strictly illogical in his actions - therefore ignore the climate change cost of every available "cheap" unit of FF. In reality man is loosely logical. As we experience more and more of the effects of climate change, as we drive the costs of renewables down in comparison to "cheap" FF and as people see those that pay 20% of what they pay for energy (through conservation and renewable systems) and that their capital costs where strictly less than 20% greater for this benefit - man will choose the renewable route. This will happen much quicker in less developed countries of course, just as these countries were quick to develop cell phone technology. Add to that the fact that citizens of these countries are not having to reduce their consumption in any way, rather, their life is greatly improved by buying a Nissan Leaf and 8 solar panels to allow motorized transportation, preferable to walking/horse. The issue is how long does it take to convince loosely logical man to get on with it? And the cost of waiting too long is beyond imagination - basically Japan's last two weeks in nearly every country on earth, only with fewer resources to deal with the problem. -
Dikran Marsupial at 02:46 AM on 27 March 2011Models are unreliable
Playing devils' advocate for a moment, if the models are as sensitive to the parameters that they can explain essentially any historical phenomena (as implied by Poptech), then why has no skeptic produced a model with a set of parameters that can explain the climate of the 20th century without CO2 radiative forcing? Has this been done? I suspect the reason is simple, the models are not that sensitive to the tuning of parameters, especially as the parameters are often constrained by knowledge of the physics, so they can't be set to completely arbitrary values. -
IanC at 02:41 AM on 27 March 2011Weather vs Climate
Mods: I have moved my post to the model thread so please remove my previous post here. Gilles and HR, I have questions for you here.
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IanC at 02:38 AM on 27 March 2011Models are unreliable
Gilles In a comment you made in the weather and climate thread, you said "there is some implicit selection of "good" parameters behind" Are you saying that models are bad because parameters that reflect reality are used? Gilles and HR, Correctly me if I am wrong, but both of you seem to have the opinion that 1) climate is sensitive to parameters/physical processes in the model, and without knowing precisely what theses parameters and unknown processes are, the outputs don't reflect reality. 2) the models that are able to replicate reality do so because the modellers found a set of parameter that works. would these two statements reasonably describe your views?Moderator Response:Sorry, I accidentally deleted your other thread's pointer to here. I asked John to restore it.[DB] Comment restored. -
Dikran Marsupial at 02:32 AM on 27 March 2011Models are unreliable
To get the discussion restarted on a more appropriate thread... Regarding the climate projection being "wrong", it is important to realise that the mean of an ensemble of model runs is not intended to be a projection of the actual observed temperatures over some period in the future. It is a projection of only the "forced component" of the climate, i.e. what happens in response to the change in forcings define in the particular scenario, assuming the effect of "internal variability" is negligible. This means that the projection isn't "wrong" if it doesn't exactly match the observed temperatures, because it isn't intended to. This is because the effect of "internal variability" is unlikely to be negligible, but it is of no interest as it is (i) quasi-cyclical and averages out to zero in the long term and (ii) irrelevant for determining the consequences of e.g. fossil fuel use. Where the "internal variability" is considered is in the spread of the model runs, which gives the stated "margin of error" of the projection for the purposes of comparing with observed temperatures. If the observed temperatures lie within the spread of the model runs, then the observations are consistent with what the models say is plausible. -
MichaelM at 01:53 AM on 27 March 2011Weather vs Climate
If climate scientists predict a global warming of 3.8 degrees by 2100 and it turns out to be wrong - it was 3.9 they will feel such fools.Moderator Response: [Dikran Marsupial] Typo fixed; exactly the meaning of GEP Box's quote! -
quokka at 01:45 AM on 27 March 2011A Plan for 100% Renewable Energy by 2050
#82 Giles, Using scenarios to but some bounds on the range of the problem and to promote critical thinking about the problem is quite valid. Indeed it is essential. I don't know what you are going ob about. -
Dikran Marsupial at 01:38 AM on 27 March 2011Weather vs Climate
The fundamental answer to the canard that "we can't even predict the weather N days in advance, so how can we predict the climate M years into the future" is "because climate projection is not based on predicting the weather, but on simulating weather and then taking averages". This sort of statistical simulation is completely standard in statistics and physics, I use them myself in my own research as do countless other statisticians, physicists, computer scientists. -
muoncounter at 01:25 AM on 27 March 2011Weather vs Climate
PT#44: Irrelevant, you did not answer the challenge. You cannot possibly know the exact location and velocity of an electron; no model can defeat the uncertainty principle. By your definition, the output of your computer is thus worthless. Another example: you cannot possibly know when a cosmic ray will alter the state of your computer's memory. Since you cannot build an effective and portable shield from muons, it has happened and will happen again. You must conclude that the output of your computer is thus inaccurate and cannot be trusted. But this thread is about weather and climate. Further off-topic digressions should be deleted. -
muoncounter at 01:03 AM on 27 March 2011Weather vs Climate
PT#41, 42: Your understanding of the process used in the real world is minimal. And your continued use of 'worthless' is another example of your redefinition of words to suit your own purposes. I suggest keeping a dictionary at your computer at all times. "any result on a computer system that is not 100% accurate ... not to be trusted" OK, run a computer simulation that reports the location and velocity of an electron in a semi-conductor to 100% accuracy. If you can't, you must therefore not trust anything on your computer, or for that matter any piece of electronics you use. Better turn the lights off, because computers run those too. Or you could actually try learning about things before you pontificate. -
muoncounter at 00:46 AM on 27 March 2011Weather vs Climate
PT#34: "includes empirical testing as verification." Not always. Monte Carlo methods were introduced for the Manhattan Project (and named by physicists with a sense of humor). There was no experimental verification until the Trinity test; if memory serves, there was some doubt as to whether or not it would set the atmosphere on fire - and they went ahead with the test. There are no experimental tests in the oil industry, until you pony up and drill a well. A dry hole is merely one of the expected outcomes of a suite of potentially valid models. Best advice remains: keep your opinions to yourself unless you actually know what you are talking about.
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