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Razo at 02:26 AM on 5 June 2014Models are unreliable
So with regards to baselines.
I can understand the need to do it to compare models, less so with perterbations of the same model. But I'm suprised that people use it when comparing models with the actual data. Its one thing to calculate and present ensemble mean, its quite another to offset model runs or different models to match the mean of the baseline. This becomes an arbitrary adjustment, not based on any physics. Could you explain this to me please?
Also, Dikran you say
"Now the IPCC generally use a baseline period ending close to the present day, one of the problems with that is that it reduces the variance of the ensemble runs during the last 15 years, which makes the models appear less able to explain the hiatus than they actually are."
You seem to be saying a higher variance is better. Having the hiatus within the 95% confidence interval is a good thing, but a narrower interval is better if you want to more accurately predict a number, or justify a trend.
Another thing to add, as I understand if the projected values are less than 3 times the variance, one says there is no result. If it is over 3 times one says there is a trend, and not until the ratio is 10, does one quote a value. looking at the variablity caused by changing the baseline, as well as the height of the red zones in post 723, the variance appears to be about 2.0C, the range of values is about 6.0 (from 1900 to 2100). Can one use thse same rules here?
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Pierre-Emmanuel Neurohr at 01:38 AM on 5 June 2014President Obama gets serious on climate change
"Most importantly, we finally have a president who is a world leader."
We - the non-American part of the world - have a leader. You are very kind to let us know.Some of us could think that even if this plan was actually successful, Americans and their leader would continue to be the most climate-destroying persons on Earth, with something like 15 to 20 t of CO2 per person per year. The US and its leader would continue to set a bad example in all matters related to the climate of the Earth through their ever-increasing obsession for raw materials and energy overconsumption, which cannot but lead to more droughts and more flooding.
It takes quite a bit of extreme nationalism to manage to not see these facts. Orwell would either laugh or cry.
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CBDunkerson at 01:10 AM on 5 June 2014President Obama gets serious on climate change
actually thoughtful wrote: "The President's policies, while an improvement, are in the category of too little to late. And likely a smokescreen for approving Keystone XL - all the while lulling the sheeple into a false sense of complacency."
Actually, given how long he has 'delayed deciding' on Keystone XL it seems very likely to me that Obama will wait until after the congressional elections this November and then kill the proposal. If he were going to approve it he should have done so by now. Delaying allows Democrats in fossil fuel states to boost their chances of election by campaigning in favor of it. Then, once the midterms are over, Obama can kill it without impacting the balance of congressional power for the remainder of his presidency.
As to, "too little to late"... I'd say rather that Obama is enacting regulations which would force a rapid phase out of coal... if that weren't already happening without them. Natural gas, wind, and solar have been shredding the coal power industry in the Unitied States. That said, these new regulations should speed up the process. Thus far, coal plants have mostly been running to 'end of life' and then shutting down in favor of other sorts of power generation. These new regulations will force many existing coal plants to shut down before reaching their end of life.
The regulations don't go far enough to completely resolve U.S. emissions problems, but again... I don't think they need to. 'Market forces' are already taking care of that. The initial fall of coal was due to natural gas, but in the past few years natural gas power development has dwindled and solar has soared... last quarter new electricity generation in the U.S. was 74% solar, 20% wind, 4% natural gas, 1% geothermal, and 1% everything else. That's 95% renewable. Obviously it will take time to replace all the existing fossil fuel based power generation, but when nearly all new electricity production developed is renewable the changeover is inevitable.
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Razo at 00:46 AM on 5 June 2014Climate is chaotic and cannot be predicted
correction:
The key phrase is *'for certain values of the parameters'*, not 'oscillating unpredictably'.
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Razo at 00:44 AM on 5 June 2014Climate is chaotic and cannot be predicted
I seem to be being critisized for not making any assertion by the moderator and making false assertions by others. So I will try to make an assertion here, to at least be worthy of the criticism. ;-)
Firstly, my previous post was adding to the definition of chaos. Although I do not know why it would be rebuted, a rebuttal would be on my definition of chaos. I didn't touch the rest of the argument.
But now I will. It's seems to me that people are confusing randomness and mathematical chaos a little.
"For certain values of the parameters, the overall movement of the atmospheric air was oscillating unpredictably"
The key phrase is 'for certain parameters', not 'oscillating unpredictably'.
"Actually proving that these indices are chaotic is exceedingly difficult, but Tziperman et al. (1994) showed in a simple model how El Niño is likely a seasonally induced chaotic resonance between the ocean and the atmosphere."
The key phrases here are 'induced chaotic resonance', which I called 'alternative equilibrium configurations', and 'proving that these indices are chaotic is exceedingly difficult'. But then, I'm not sure if the next sentance is correct:
"Chaotic influences from oceans and volcanoes etc. makes both weather more unpredictable and creates the unpredictable part of the 'wiggles' around the average trend in climate"
That is, although volcanic eruptions are chaotic in the regular sense or the word and can impact the climate greatly, do they involve indicies that are chaotic at certain values? Also, I don't think the formation of high pressure air masses come about after thier chaotic parameters reach a critical value.
How chaos could impact climate might be more like this, I think. If one could show that global warmimg is effecting the chaotic indicies that cause ElNino to the degree that it becomes a more frequent and long lasting event, ie, the regular weather, that could impact climate. Or maybe if one could show that the pacific trade winds, that are presently causing a slow down of average global surface temperatures, are an induced chaotic resonance caused by global warming itself.(These are just absolute hypothetical ideas by me, I am not saying this is happening. the point is indicies reaching critical values)
Regarding Lorenz's chaotic systems of rising warm air, well its on the scale of local weather thats going on all the time. I would guess it is accounted for emperically in the models as required (depending on the purpose of the model: forcasting, climate change, or downscaling etc)
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dhogaza at 00:12 AM on 5 June 2014President Obama gets serious on climate change
"Why didn't he do this the day he entered office in 2008?"
Because the Supreme Court ruling affirming the right of the EPA to regulate cross-state emissions was announced on April 29, 2014, perhaps? Remember that an appeals court had struck down that right a couple of years earlier.
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dhogaza at 00:10 AM on 5 June 2014President Obama gets serious on climate change
"Howabout "FUSION" our own earth bound sun feeding electricity into a revamped National Grid by 2030...there's a goal!!"
If past history is any indication, in 2030 fusion will still be 50 years in the future, just as it is today.
Money is being spent on fusion research. Progress is still unimpressive. Perhaps the nut will crack someday, perhaps it will always be a dream.
But criticizing Obama for not banking on fusion is rather silly.
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geoffrey brooks at 22:34 PM on 4 June 2014President Obama gets serious on climate change
I can see from the howls of protest from the coal industry and coal states that:
1) Coal becoming only 30% (down from 40%) of the USA electrical power by 2030 - is too little too late. A target the USA is unlikely to meet with the measly greedy politicians we have in charge.
2) If US clean coal technology truly exists - it should be given to China and other coal burners - and we should help implement it. A $5 tax on oil to invest in this and other clean energy - such as fusion.
3) We should keep the Carbon in the ground - coal is the dirtiest and most expensive to clean up. The 2030 goal should be less than 5% electricity from coal
4) We already subsidizes the farming industry not to grow crops...
why not the coal industry not to mine it???
A tax on Natural Gas (much cleaner) used to generate electricity could be levied and given to the coal industry to keep their coal in the ground. The monies for not mining should be spent on re-educating the work-force, maintaining their pensions, providing transitional payments, and ensuring that they get excellent health benefits - not to enrich the greedy. If the miners are not mining, the coal will stay where it belongs in the ground - NOT in the air.
5) President Obama - you need imagination, planning and foresight to help save the planet. Lets see some. Howabout "FUSION" our own earth bound sun feeding electricity into a revamped National Grid by 2030...there's a goal!!
Geoffrey Brooks
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Dikran Marsupial at 18:56 PM on 4 June 2014Climate is chaotic and cannot be predicted
Razo, I should point out that just because weather is chaotic that does not imply that climate (the long term statistical properties of the weather) is similarly chaotic. It is not difficult to think of other phsyical systems where this is the case, for example a double pendulum in the presence of an electromagnet.
Sadly expertise in one field is often a recipe for the Dunning-Kruger effect when moving into a different field as it can blind you to the important differences between fields and give undue confidence in ones ability that makes you unable to see your mistakes. The climate modellers are experts in their field, best to understand first and make assertions afterwards.
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calyptorhynchus at 15:05 PM on 4 June 2014President Obama gets serious on climate change
oops 2009
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calyptorhynchus at 13:12 PM on 4 June 2014President Obama gets serious on climate change
Why didn't he do this the day he entered office in 2008?
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Tom Curtis at 09:59 AM on 4 June 2014Climate is chaotic and cannot be predicted
Razo @71, I am going to disagree with TD. You have not shown the relevance of your claims. You are not a researcher into climate models drawing inspiration from another field. Nor do you show how that inspiration from another field should effect our thinking about climate models. At best you have pointed out that in another field there are certain problems and that it is possible that the same problems exist for climate models. As a response to that, pointing out that it is also possible that they do not exist for climate models is an adequate rebutal.
In this case, however, we can make a stronger rebutal because we know future climate states are constrained by the requirements of conservation of energy, and hence constrained by the forcing history. As such, it is analogous to a hollow ball containing a 3D triple pendulum running down a u shaped track. The detailed motion of such a ball will be chaotic, but the mean path and velocity of the ball will be well constrained, and departures from those means will be short term variations only.
Moderator Response:[TD] Tom, I didn't write that Razo showed the relevance of his/her claims, only that he/she at least tried this time. Better than before. Nonetheless, Razo's followup post was mere continuation of his/her sermonizing without addressing the specific features of climate models that have been explained to him/her; so I deleted it.
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Razo at 08:33 AM on 4 June 2014Climate is chaotic and cannot be predicted
i will respond still to this question as it is directed to me. You may delete them if you wish.
TC, its still relevant because the mathematics of physical phenomena can be very similar between many fields in the physical sciences: electromagnetics, fluid dynamics, thermodynamics...(it's been many years ago now since university). climate models integrate partial differential equations. One can get inspiration from other fields, and many breakthroughs are done this way.
I don't want to take more room on this post for this, but it's a fundemental point.
Moderator Response:[TD] Good, at least you explained what you claim is relevant. However, you continued to fail to address how the specifics of climate models that have been explained to you are trumped by the "lessons" of models of entirely different domains.
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Mal Adapted at 08:28 AM on 4 June 2014President Obama gets serious on climate change
"We finally have a president that understands science."
Well, yes. My votes for Obama have been decisions on the margin, like all my votes have become over the years. He's done some things I really don't like, but since the only 2012 GOP presidential primary candidate to explicitly support both the teach of Evolution in public schools and the scientific consensus on AGW dropped out of the race early, and several of the rest actually renounced their previous support for the consensus, my choice for Obama was clear.
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Tom Curtis at 08:18 AM on 4 June 2014Climate is chaotic and cannot be predicted
Razo @69, so? Did the person in question have experience of climate models, and tell you that the same considerations applied to climate models? Did they explain how the climate was supposed to evade the limits placed by conservation of energy on variability in climate? If not, your analogy has no relevance to the discussion, and your implied argument from authority is irrelevant.
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Razo at 07:55 AM on 4 June 2014Climate is chaotic and cannot be predicted
I would point out the person that told me this was a person that could read Bell laboratory research on superconductors and say that the same math can apply to solid mechanics and bifurcation, ST Ariaratnam.
Moderator Response:[JH] So what! Name dropping is no substitute for well-reasoned comments that are relevant to the OP, or in response to someone else's on-topic comment
Per the SkS Comments polciy (which you should read in its entirety):
The purpose of the discussion threads is to allow notification and correction of errors in the article, and to permit clarification of related points.
Very few of your posts have met this standard.
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Razo at 07:53 AM on 4 June 2014Climate is chaotic and cannot be predicted
Okay then.
i offered the phrase 'alternative equilibrium configuration' as a concept to help people understand chaotic systems changimg states. Before I used to have a kind of mythical understanding of bifurcation problems. When it was told to me, it was a real help in understanding.
Second I continue the very simple analogy of modelling columns to suggest requirements for a model: the alternative configuration has to be programmed into the model, the numerical algorithm has to be very robust.
these may seem trivial to some, but I don't think they are. I am not making any statement on the worthiness of existing GCM.
Moderator Response:[TD] This site is not an appropriate place for you to ruminate on topics marginally or totally irrelevant to climate change. You have responded to moderator requests to specify the relevant point you are trying to make by posting more ruminations and your own admission that you are not addressing the "worthiness of existing GCM." We will begin to simply delete your posts that are irrelevant to the topic.
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John Hartz at 07:14 AM on 4 June 2014Climate is chaotic and cannot be predicted
All: Please do not Post any responses to Razo until he makes a specific point about the OP. .
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Tom Curtis at 07:12 AM on 4 June 2014Climate is chaotic and cannot be predicted
Razo @64, when it comes to chaos, many people who are slightly informed probably have the lorenz attractor in mind as archetypical of strange attractors:
With the lorenz attractor, after a given number of steps (successive evaluatons of the formula), it is not even possible to predict which lobe you will be in so that you truly have a bifurcation. The bifurcation is reversible, however, which makes it quite unlike column buckling. More importantly, the lonrenz attractor is not the only strange attractor, and not all strange attractors have a multilobe shape. The rossler attractor, for example, has a single lobe:
With the rossler attractor, it is not possible to tell well in advance on which side of the "orbit" you will be, but you will generated values will always orbit the same point. The analogy to bifurcation fails.
The climate system is even more precictable than a rossler attractor (in one sense). Specifically, thermodynamics requires the climate system to have a net zero energy exchange between the planet and space over a very short term. Consequently while it is not possible to predict far in advance exactly how far the planet will diverge from that equilibrium point within limits, it is possible to predict that it will track the equilibrium point very closely (within plus or minus 0.3 C from observations over the holocene).
There is a possibility, however, of genuine bifurcations. Melting of ice sheets, release of methane, large scale vegetative die back and other possible consequences of global warming could suddenly shift the equilibrium point. Such sudden shifts, however, are almost certainly towards a warmer climate. That is, to the extent that models fail to capture such bifurcations, they underestimate the potential risk from global warming. It is strange that when pseudo-skeptics plead the chaos of the climate system, they always assume that that chaos is predictable, and will counter the effects of global warming. We know enough, however, to know the genuine bifurcations are unpredictable, and will make things worse.
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Razo at 06:13 AM on 4 June 2014Climate is chaotic and cannot be predicted
I could add to my last post ^^^, about modeling column buckling. Its a rather simple problem but is analogous to bigger chaos problems, I think.
In order to model column buckling you need to do equilibrium in the deformed configuration. That is, the other possible degrees of freedom and their physcal behaviour have to be introduced in to the model. For numerical models, the increment steps and constiuative relations algorithms must be able to handle large changes.
Moderator Response:[JH] What is the point you are attempting to make?
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Razo at 05:56 AM on 4 June 2014Climate is chaotic and cannot be predicted
Strangely, there are not a lot of comments on this topic. LOL
The little I know on chaos I would like to share. As it was explained to me by ST Ariaratnum, an apparent god in random vibrations. Chaotic systems are analogous to bifurcation problems, like column buckling. As a forcing reaches a critical value, large changes in the system can occur.
A column buckles when it reaches its critical load. Ariaratnum however prefered to call it the 'alternate equilibrium configuration'. So the column buckles when it reaches a state where it can resist the load by deforming in a different way. At this forcing, this altrenate configuration stores less potential energy (this last sentance I don't remember well).
Moderator Response:[JH] What is the point you are attempting to make?
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actually thoughtful at 05:11 AM on 4 June 2014President Obama gets serious on climate change
The President's policies, while an improvement, are in the category of too little to late. And likely a smokescreen for approving Keystone XL - all the while lulling the sheeple into a false sense of complacency.
I realize that appears a tad cynical. I submit it is also accurate.
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shoyemore at 04:57 AM on 4 June 2014President Obama gets serious on climate change
This is surely not a complete coincidence? Obama and Xi must have been having some contacts on the matter.
Absolute cap to come into effect, climate adviser says on the day after US announces ambitious carbon plan
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KR at 04:44 AM on 4 June 2014Models are unreliable
nickels - If you feel that the climate averages cannot be predicted due to Lorenzian chaos, I suggest you discuss this on the appropriate thread. Short answer: chaotic details (weather) cannot be predicted far at all due to nonlinear chaos due to slightly varying and uncertain detailed starting conditions. But the averages are boundary problems, not initial value problems, are strongly constrained by energy balances, and far more amenable to projection.
Steve Easterbrook has an excellent side-by-side video comparison showing global satellite imagery versus the global atmospheric component of CESM over the course of a year. Try identifying which is which, and if there are significant differences between them, without looking at the captions! Details (weather) are different, but as this model demonstrates the patterns of observations are reproduced extremely well - and that based upon large-scale integration of Navier-Stokes equations. The GCMs perform just as well regarding regional temperatures over the last century:
[Source]
Note the average temperature (your issue) reconstructions, over a 100+ year period, and how observations fall almost entirely within the model ranges.
Q.E.D., GCMs present usefully accurate representations of the climate, including regional patterns - as generated by the boundary constraints of climate energies.
---
Perhaps SkS could republish Easterbrooks post? It's an excellent visual demonstration that hand-waving claims about chaos and model inaccuracy are nonsense.
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Anthony10658 at 04:15 AM on 4 June 2014Republican witness admits the expert consensus on human-caused global warming is real
Another misdirection. Let's forget 97% and just say "Most" or "almost all" research point to human industrial and agricultural byproducts as being the cause of rising global temperatures. Then the debate moves to -1) is this bad and 2) if yes what can and should we do about it.
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Dikran Marsupial at 03:32 AM on 4 June 2014Models are unreliable
"The future is uncertain nonetheless."
A statement of the exceedingly obvious. However you have not written anything that would support the contention that the future is any more uncertain than the model projections state, or that the models are not useful or basically correct.
"If we had observations of the future, we obviously would trust them more than models, but unfortunately …… observations of the future are not available at this time. (Knutson & Tuleya – 2005)."
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nickels at 03:16 AM on 4 June 2014Models are unreliable
Oh, and this inability to integrate the model forward with accuracy doesn't even touch on the fact that the model itself is an extreme approximation of the true physics. Climates models are jam-packed with adhoc parameterizations of physical process. Now the argument (assuming the model was perfect) is that averages are computable even if the exact state of the climate in the future is not. Its a decent arguement, and in general this is an arguable stance. However, there is absolutely no mathematical proof that the average temperature as a quantity of interest is predictable via the equations of the climate system. And there likely never will be. But, again, all of this is not a criticism of climate modelling. They do the best they can. The future is uncertain nonetheless.
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Composer99 at 03:11 AM on 4 June 2014Antarctica is gaining ice
edaaaa - Please re-post your comment to a thread where it is on topic.
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nickels at 03:07 AM on 4 June 2014Models are unreliable
@scaddenp, in fact the navier stokes are absolutely non-predictable. This is what the whole deal with Lorenz is all about. In fact, we cant event integrate a simple 3 variable differential equation with any accuracy for anything but a small amount of time. Reference:http://www.worldscientific.com/doi/abs/10.1142/S0218202598000597
Now, if we assume that climate scientists are unbiased (I've been in the business, this would be a somewhat ridiculous assumption), the models would provide our BEST GUESS. But they are of absolutely NO predictive value, as anyone who has integrated PDE's where the results matter (i.e. Engineering) knows.
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KR at 02:36 AM on 4 June 2014There's no empirical evidence
Note: I am not stating that Von Storch is a pseudo-skeptic, just that the selection of 1998 is statistically ill-considered, and that claims of trends from that time point are not supported by the data.
Further discussion on this topic (i.e. no warming since...) should probably move to this thread, as it is somewhat off-topic here.
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Dikran Marsupial at 02:34 AM on 4 June 2014There's no empirical evidence
Just to add to KR's comment, if you look at a comparison of the AR4 SRESA1B model ensemble with the observations (courtesy of RealCLimate):
you can see that the observations were further into the upper tail of the envelope of model runs than they are into the lower tail of the distribution in recent years.
Now, ask yourself why the skeptics were not interested in pointing out the model observation "inconsistency" in 1998. Cherry picking indeed, the 1998 one clearly wasn't ripe. ;o) -
KR at 02:19 AM on 4 June 2014There's no empirical evidence
Razo - WRT Von Storch and the avoidance of ENSO effects on trends, it is notable that: if you select as an endpoint an extrema value from a time series, the statistical significance of anything terminating there is much much lower.
There's a good discussion of this over on Tamino, under Cherry-p. Von Storch followed in the trail of many a pseudo-skeptic, and selected the 1998 El Nino (3-sigma in scale) as one of his trend endpoints. Without noting the fact that it was indeed a time series variation extrema.
In the presence of such selection of an extrema, the required p-value for statistical signifcance can be 10x normal!! That's because in any system with noise you can find short trends up and down, meaning once you start selecting extrema endpoints, you need far more supporting data to make your claim(s). Supporting data that simply doesn't exist in the temperature record.
1998 trend claims are the essence of cherry-picking, of selecting a subset of data that appears to support a claim while ignoring the remainder of the data that contradicts that claim. It's a "fallacy of selective attention, the most common example of which is the confirmation bias", and such claims are logical fallacies.
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edaaaa at 01:28 AM on 4 June 2014Antarctica is gaining ice
I simply ask a factual question as to the basis of the study pointing to 97.1% peer reviwed abstracts. The opening excerpt quantifies the study in the following "...peer-reviewed scientific literature, examining 11 944 climate abstracts from 1991–2011 matching the topics 'global climate change' or 'global warming'. We find that 66.4% of abstracts expressed no position on AGW, 32.6% endorsed AGW, 0.7% rejected AGW and 0.3% were uncertain about the cause of global warming. Among abstracts expressing a position on AGW, 97.1% endorsed the consensus position that humans are causing global warming..." - After doing the math - Including the small percent of those that do not support AGW) doesnt this mean that 97.1% of 4014 (or so) abstracts and not 97.1% of the science "community" or scientists agree ?? And if so, in the interest of truth and fact, dont you seek to clarify this within the media so they can more intelligently inform the public ?? - http://iopscience.iop.org/1748-9326/8/2/024024/pdf/1748-9326_8_2_024024.pdf
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heb0 at 00:17 AM on 4 June 2014Republican witness admits the expert consensus on human-caused global warming is real
"The science isn't settled" in much the same way that "the models are wrong." Just as models are by definition not completely accurate, scientific understanding of the climate is incomplete. But both of those statements, on their own, are useless, and both of them could be said about any field of scientific research, no matter how universally accepted. They require quantification to be anything meaningful. Yet, those who trumpet them don't seem interested in quantification, only in spreading that message.
I don't know much about Richard Tol, but lately he strikes me much like Roger Pielke: stubbornly contrarian yet slipperily vague. If memory serves me correctly, both have a strange habit of pedantically seizing on miniscule points of contention and then trying to use that to justify rejecting much larger parts of the science. When you call them on it, it's almost impossible to get them to admit which part of the conensus they disagree with, yet they will, if unchecked, make pretty denial-ish claims. It's fitting that they were both invited as witnesses.
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Alexandre at 22:45 PM on 3 June 2014Republican witness admits the expert consensus on human-caused global warming is real
I don't expect "skeptics" to build on previous conclusions or aknowledged evidence. It wouldn't surprise me if Tol claimed that "the science isn't settled" next month. Climate inactivity does not rely on coherence - quite the opposite.
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Tom Curtis at 20:01 PM on 3 June 2014Human CO2 is a tiny % of CO2 emissions
scaddenp @257, based on ice core data, there is approximately a 90 ppmv rise in CO2 concentration between glacial and interglacial. That yields a CO2 increase per degree C between 11.25 and 30 ppmv per degree C with the former for an 8 C increase in temperature, and the later for an assume 3 C increase. A reasonable central estimate is 18 ppmv per degree C (5 degree increase). For the 0.8 C increase in temperature experienced since the industrial revolution, that yields and expected increase of 14.4 ppmv or 12% of the CO2 increase todate. As you say, it is unlikely that all of that increase would have happened over so short a time.
As an alternative emperical measure, taking the global temperatur anomaly from 1010 AD to 1800 AD (Mann 2008) and ice core CO2 records, the regression shows an 8.1 +/- 2.9 ppmv increase in CO2 per degree C. Based on that regression the expected increase for the global temperature increase since the pre-industrial of 0.8 C is 6.5 +/- 2.3 ppmv of CO2, or 3.5 - 7.3%. The time resolution of the CO2 record is 75 years, and I used a 75 year average of the temperature record to maintain equivalent resolution. That regression, therefore, yields a reasonable but not precise estimate of the increase that would have occurred from temperature increase alone.
As far as showing the absurdity of the pseudo-skeptic claims that the increase in atmospheric CO2 was caused by the temperature increase goes, the difference between 3% and 10% is not relevant. Therefore I indulged my habit of using conservative (for my position) estimates for rough figures where it makes little difference. The long and short, then, is that, yes I agree with you. But I don't think the difference is enough to warrant keeping track of for rough estimates.
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Dikran Marsupial at 18:54 PM on 3 June 2014Models are unreliable
Razo wrote "I can appreciate baseline study is a little more complex. I think the topic of my post 706 is not effected by this."
No, as KR pointed out, baselining is actually a pretty simple idea. It is a shame that you appear to be so resistant to the idea that you have misunderstood this and are trying so hard to avoid listening to the explanation of why the good fit is obtained during the baseline period (and why it is nothing to do with the models themselves). You will learn very little this was as most people don't have the patience to put up with that sort of behaviour. However, ClimateExplorer allows you to experiment with the baseline period to see what difference it makes to the ensemble. Here is an CMIP3 SRESA1B ensemble with baseline period from 1900-1930:
here is one with a baseline period of 1930-1960:
1960-1990:
1990-2020:
I'm sure you get the picture. Now the IPCC generally use a baseline period ending close to the present day, one of the problems with that is that it reduces the variance of the ensemble runs during the last 15 years, which makes the models appear less able to explain the hiatus than they actually are.
Now as to why the observations are currently in the tails of the distribution of model runs, well it could be that the models run too warm on average, or it could be that the models underestimate the variability due to unforced climate change, or a bit of both. We don't know at the current time, but there is a fair amount of work going on to find out (although you will only find skeptics willing to talk about the "too warm" explanation). The climate modellers I have discussed this with seem to think it is "a bit of both". Does it mean the models are not useful or skillful? No.
Razo also wrote "I wanted to point out to Dikran Marsupial, that the point of my post 706 was that the model that includes man made forcings only seems to be reducing the large error of the natural forcing only model in the 1850s when they are combined."
Well perhaps you should have just asked the question directly. I suspect the reasons for this are twofold: Firstly it is to a large extent the result of baselining (the baseline period for these models is 1880 to 1920), if you made the "error" of the "natural only" models smaller in the 1850s, that would make the difference in the baseline period bigger than currently shown and hence this is prevented by th ebaselining procedure. The same baselining causes the "anthropogenic model" to have large "errors" from the 1930s to the 1960s. The primary cause is baselining. Now if you have a better model that includes both natural and anthropogenic forcings, you get a model that doesn't have these gross errors anywhere, because the warming over the last century and a half has had both natural and anthropogenic components. So this is no surprise.
Now it is a shame that you didn't stop to find out what baselining is and why it is used when you first saw it on Tamino's blog, rather than carry on trying to criticise tghe models with incorrect arguments. Please take some time to do some learning, don't assume your background means you don't have to start at the beginning (as I had to), and dial the tone back a bit.
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scaddenp at 15:04 PM on 3 June 2014Human CO2 is a tiny % of CO2 emissions
TC. I would have to humbly disagree with you on this one. I dont believe that we would have received a 10% increase - yet. Ocean mixing delays that solubility response.
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Tom Curtis at 14:50 PM on 3 June 2014Human CO2 is a tiny % of CO2 emissions
rdbachel @254, you may be interested to read this summary of how we know the CO2 rise to be anthropogenic. The mass balance argument (we know how much we have emitted, and it is more than the increase in CO2) and the isotope arguments mentioned by scaddenp are the most important pieces of evidence, but no the only ones.
To slightly complicate things, had the temperature increase we experienced over the last century occurred without any increase in anthropogenic emissions over pre-industrial levels, we would still have experienced about 10% of the increase in CO2 levels that have actually occurred. This is known due to the known (from experiment) solubility of CO2 in water with temperature, and from comparisons to CO2 increases in past eras when temperatures have risen (as at the end of glacials). However, the rise in directly anthropogenic CO2 has been far faster than that potential increase. That is known from mass balance, and from the fact that ocean acidity increased over that period whereas it would have decreased if the CO2 increase in the atmosphere was due to thermal sources. Further, even if some of the increase should be attributed to temperature, that temperature increase is itself primarilly anthropogenic so that any CO2 increase in the atmosphere caused by it is also anthropogenic.
So called "skeptics" about AGW sometimes argue that the CO2 increase is natural and due to temperature rise. To do so they entirely ignore the rates at which CO2 rises in the atmosphere with increased global temperature (which are too small by a factor of 10 to account for the actual rise experienced), and the concurrent increase in ocean acidity, which proves the amount of CO2 dissolved in the ocean is increasing at the same time.
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scaddenp at 14:38 PM on 3 June 2014Nuclear testing is causing global warming
While they take a lot of energy, on the scale of other things, it is insignificant. World production of Uranium for all purposes has never exceeded 70,000 tonnes per year. World production of say coal by comparison is around 3,000,000,000 tonnes per year.
If you assumed that energy to extract uranium was say 10 times as much as that required to extract coal, (actually pretty similar), then energy cost from mining uranium is just 0.02% of that spent mining coal.
All the heat that we generate from all our industry in whatever form amounts to only 0.028W/m2. The heating from human-produced greenhouses gases is 2.9W/m2 by comparison. (See the "its waste heat" argument)
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scaddenp at 14:25 PM on 3 June 2014Human CO2 is a tiny % of CO2 emissions
Firstly, we know with reasonable accuracy how much coal and petroleum are being burnt every year. We know that not all of that stays in the atmosphere (or the rise in CO2 would be larger). At the moment, the sea is moping up some of those emissions and becoming less alkaline in the process (that is also measured) so CO2 is not coming from the sea. The change in the pH allows us to calculate how much CO2 is being dissolved. As the oceans warm, this will change and eventually the oceans will begin to emit CO2 - hopefully not in the next century or so.
Sources of CO2 have different ratios of the carbon isotopes C14, C13, C12. For instance, fossil fuels have no C14 (it is short-lived). You can look at ratios of these isotopes in the air and water and check if the proportions match emissions from humans or some other source.
The "hole in the ozone layer" is a pictureque but inaccurate description. All the gases (including ozone) in the atmosphere are bound to the earth by gravity. The ozone layers doesnt trap any gas. Ozone is produced in tiny amounts in upper atmosphere by interaction of oxygen with UV radiation. This has a very important effect in shielding the lower atmosphere (where we live) from UV. Chemicals released into the atmosphere (CFC) are chemically destroying ozone especially above Antarctic so that it is much thinner ("the hole") in those places.
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rdbachel at 13:59 PM on 3 June 2014Human CO2 is a tiny % of CO2 emissions
I was wondering if somebody could explain a part of the answer to me? Fistly, the answer states that rises have been noticed. If this is true, why is the complete rise solely based on humans and why can this not be a dramatic rise naturally occuring? What is to say that this is a new rise not previously seen in history before that is natural? I do, think that humans contribute to a rise in co2....to clarify. Secondly, I am assuming that the things I heard on tv were true and that there is a hole in the ozone. If there is a hole, why wouldnt the co2 just escape through that hole? Why wouldnt oxygen and nitrogen escape through that too?
Im really just trying to get some answers here. The problem, from my perspective and I think a good majority of others, is that as a lot of the comments show, this is science. I am not a scientist. That doesnt mean I was raised to trust anybody telling me what they have is true. I need this explained is some everyday, simple language please.
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rdbachel at 13:44 PM on 3 June 2014Nuclear testing is causing global warming
Hello everyone...well myself, right now. I think that the point of this argument was not that the nuclear weapons themselves have contributed to warming. I believe that the point of this argument is that the process of making the nuclear material requires massive amounts of fossil fuels to buid facilities, dig ore, refine, transport and then fire. Taking a conservative estimate of 2000 nuclear weapons fired since 1940 the amount of fossil fuel emissions would be a great number!
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michael sweet at 12:04 PM on 3 June 2014Models are unreliable
Razo,
Calibration of Global Climate Models is difficult. I understand that they are not calibrated to match the temperature trend (either for forcast or hindcast). The equations are adjusted so that measured values like cloud height and precipitation are close to climatological averages for times when they have measurements (hindcasts). The temperature trends are an emergent property, not a calibrated property. This also applies to ENSO. When the current equations are implemented ENSO emerges from the calculations, it is not a calibrated property.
Exact discussions of calibration seem excessive to me. In 1894, Arrhenius calculated from basic principles, using only a pencil, and estimated the Climate Sensitivity as 4.5C. This value was not calibrated or curve fitted at all— there was no data to fit to. The current range (from IPCC AR5) is 1.5-4.5C with a most likely value near 3 (IPCC does not state a most likely value). If the effect of aerosols is high the value could be 3.5-4, almost what Arrhenius calculated without knowing about aerosol effects. If it was really difficult to model climate, how could Arrhenius have been so accurate when the Stratosphere had not even been discovered yet? To support your claim that the models are not reliable you have to address Arrhenius' projection, made 120 years ago. If it is so hard to model climate, how did Arrhenius successfully do it? Examinations of other model predictions (click on the Lessons from Past Predictions box to get a long list) compared to what has actually occured show scientists have been generally accurate. You are arguing against success.
A brief examination of the sea level projections in the OP show that they are too low. The IPCC has had to raise it's projection for sea level rise the last two reports and will have to significantly increase it again in the near future. Arctic sea ice collapsed decades before projections and other effects (drought, heat waves) are worse than projected only a decade ago. Scientists did not even notice ocean acidification until the last 10 or 20 years. If your complaint is that the projections are too conservative you may be able to support that.
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scaddenp at 11:43 AM on 3 June 2014Models are unreliable
Razo: So? That doesnt make them unreliable nor unskillful. You seem to saying "its complex therefore they must be wrong". Much more importantly, you dont have to rely on models to verify AGW. Nor to see that we have problem. Empirically sensitivity, is most likely between 2 and 4.5. From bottom up reasoning, you need a large unknown feedback to get sensivitity below 2. (Planck's law get you 1.1, clausius-clapeyron gives you 2, with albedo to follow). And as for models, the robust predictions from models seem to be holding up pretty good. (eg see here ).
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John Hartz at 11:02 AM on 3 June 2014There's no empirical evidence
Razo: Here are some more facts about GCMs for you to ponder.
Climate Models Show Potential 21st Century Temperature, Precipitation Changes
Posted Sep. 27, 2013, NASA/GISS"New data visualizations from the NASA Center for Climate Simulation and NASA's Scientific Visualization Studio at Goddard Space Flight Center, Greenbelt, Md., show how climate models used in the new report from the United Nations' Intergovernmental Panel on Climate Change (IPCC) estimate possible temperature and precipitation pattern changes throughout the 21st century.
"For the IPCC's Physical Science Basis and Summary for Policymakers reports, scientists referenced an international climate modeling effort to study how the Earth might respond to four different scenarios of carbon dioxide and other greenhouse gas emissions throughout the 21st century. The Summary for Policymakers, the first official piece of the group's Fifth Assessment Report, was released Fri., Sept. 27.
"This modeling effort, called the Coupled Model Intercomparison Project Phase 5 (CMIP5), includes dozens of climate models from institutions around the world, including from NASA's Goddard Institute for Space Studies."
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Tom Curtis at 10:43 AM on 3 June 2014There's no empirical evidence
Razo @208:
1) von Storch et al (unpublished*) shows a temperature increase over the 15 year interval at 40% of what they claim to be the preceding 30 year trend in the only fully global temperature series used (GISS). They state:
"Estimates of the observed global warming for the recent 15-year period 1998-2012 vary between 0.0037 C/year (NCDC), 0.0041 C/year (HadCRUT4) and 0.008 C/year (GISS). These valuesare significantly lower than the average warming of 0.02 C/year observed in the previous thirty years1970-2000."
We immediately face problems in that 1970-2000 inclusive is a 31 year period so we do not know which trend they used. However, the Jan 1971 - Dec 2000 (Jan 1970- Dec 1999) trends are:
GISS: 0.166 +/- 0.058 (0.164 +/- 0.58) C/decade
NOAA: 0.167 +/- 0.054 (0.165 +/- 0.54) C/decade
HadCRUT4: 0.174 +/- 0.056 (0.168 +/-0.057) C/decade
Which ever trend you choose, von Storch et al have exagerated the preceding thirty year trends by 15-20%, thereby exagerating the extent of the slow down in temperature increase.
Further, they give incorrect values for the 15 year trends as well. The actual values are:
GISS: 0.073 +/- 0.147 C/decade
NOAA: 0.04 +/- 0.137 C/decade
HadCRUT4: 0.047 +/- 0.14 C/decade
Consequently the actual (reported by von Storch et al) ratio of trends using 1971-2000 for the 30 year trends are:
GISS: 0.44 (0.4)
NOAA: 0.24 (0.185)
HadCRUT4: 0.27 (0.205)
They therefore exagerate the slowdown by 10 or more percent.
2) von Storch et al avoid mentioning ENSO events to an extraordinary extent. There only reference is a casual mention that models have difficulty modelling ENSO events. He nowhere mentions the fact that 1998 was one of the largest El Nino events on record which, coming at the end of the thirty year trend and the start of the 15 year treand, exagerates the former while depressing the later. Nor does he mention the strong La Nina in 2008, nor the record La Nina (SOI Index) of 2011/2012. Nor does he mention the strong La Nina in 1974/75 (second strongest on record in the SOI). These La Ninas exagerate the 30 year trend, and supress the 15 year trend.
As a side note, von Storch et al's claims about the inability of models to model ENSO events are not strictly true. They were true of about half of models used in the CMIP3 intermodel comparison and the IPCC AR4; but it is not longer true of those used in CMIP5 and AR5. What models cannot do is generate ENSO events with the same timing as real ENSO events for the simple reason that that timing is essentially random.
3) von Storch et al make no allowance for the fact that 1998 was well above the temperature trend, or that 2011/12 by virtue of the La Nina were presumably well below it.
This is extraordinary. It means his entire argument is analogical to a person trying to prove that water does not settle to the same level because lines drawn from a point at the crest of a wave to other parts of the water surface have, on average, a negative slope.
Of course trends drawn from a peak well above the trend do not have the same statistical distribution as trends drawn from points on the long term trend line. For them to have the same statistical distributions, the series of data points (temperature records) must be a random walk. That the twentieth and early twentieth temperature record constitutes a random walk is a flat contradiction of the predictions of the models and climate scientists - yet that is the implicit assumption in von Storch et al's criticism. This flaw is made worse by both the fact that von Storch et al use a trend not only from a "peak", but to a "trough", and by the fact that they eschew any discussion of this issue.
IMO the statistical analysis in von Storch et al falls to the level of pseudo-science. I was greatly disappointed to see that von Storch had sunk that low.
* The article by von Storch et al was never published in any journal, but merely distributed on the internet. It follows, of course, that it is not peer reviewed.
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Razo at 10:01 AM on 3 June 2014Models are unreliable
michael sweet,
When I am talking about calibration, I look at it more like this (slightly simplified version follows):
Computer models are based on math. Math is equations. For curve fitting or trends one guesstimates an equation based on a graph. For more physical models, the equations are derived from basic principles. In both cases some 'calibration' is done to establish the equation's parameters. In the latter case, sometimes its easy like g=9.81 m/s2.
As I understand, GCMs basically integrate Navier Stokes equation. These are big and complicated. They can however be broken up into different pieces and a large part of the calibration can be done in parts. Some of the paramteres are omitted and some are estimated using yet another equation, and maybe curvefitting.
On top of this, computers don't do math like humans. They usually break it into small steps which they perform fast. So the solution process itself is approximate.
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Jim Hunt at 08:38 AM on 3 June 2014Republican witness admits the expert consensus on human-caused global warming is real
In my own article about the hearing I likened the proceedings to "a pantomime":
http://econnexus.org/the-scientific-consensus-on-climate-change/
I hope this doesn't sound overly political, but according to the IPCC AR5 WG I SPM “Warming of the climate system is unequivocal”. In the subsequent press release Lamar Smith said that:"A distinguished panel of experts involved in the IPCC and National Climate Assessment process unanimously stated that the science of climate change is “not settled,” as the President and others often state unequivocally."
I'm from the other side of the Atlantic, but it seems to me that an enterprising US lawyer could make a good case that Rep. Smith is guilty of libeling the President of the United States of America!
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MThompson at 08:36 AM on 3 June 20142014 SkS Weekly News Roundup #22B
In reference to knaugle on entry 11, you might take a look at the National Snow and Ice Data Center figure 6b. This shows that 2014 Antarctic sea ice is well above the two sigma variation of historic data. It would not be at all surprising that this trend contiues through winter (southern hemisphere). I'm making no attempt to identify the verbatum data source Mr. Bastardi referenced, but his assertion is likely true.
Having said that, you must be admonished that increasing Antactic sea ice in itself is scant evidence of global warming, one way or the other.
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