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dana1981 at 06:36 AM on 5 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Ugh, well I just wated 5 minutes of my life reading Tisdale's post. If Tisdale ever actually says anything intelligent, then let me know. Until then I prefer not to waste my time reading his drivel.
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Jose_X at 06:21 AM on 5 October 2013Residence Time and Prof Essenhigh
funglestrumpet @14:
Man is adding CO2 and some of that is leaking back out. This we all seem to agree on. But..
The argument described at the top is a simplified model. Too simplified. It assumes that the atmosphere is a pipeline. It obviously is not. While an engine might have most of the air coming in at one location then move to exit elsewhere, perhaps crudely approximated as a single file queue, the atmosphere has lots of CO2 rise high to areas where there are few sinks. There is no physics that I know that suggests a model of a queue applies. The CO2 is *not* following a path single file that takes it way up high and then spins and comes down to leave at the ground level. That 5 year figure is the result of a simplified queue model. You can forget about it unless perhaps you want to believe the man-made CO2 entering and leaving the atmosphere is doing so in as a queue.
Another analogy is the difference between fast moving draft air in a narrow cooridoor that is open at each end. This is like a queue. The atmosphere instead is like a huge balloon with two openings near each other, where one opening slowly adds air and the other slowly removes it. In this balloon example, we have nothing resembling a queue.
Besides that the flow is not like a queue IMO, you are asking a different question than what is presented above. The five year is supposed to be the average time for CO2 to move into the atmosphere and back out, but the question you are asking is how long before we return to the same quantity of CO2 we had if we stop adding CO2. You care about how long before the air in the balloon gets back to the same quantity if we remove one of the several drivers adding air into the balloon.
If we stop adding, there will be a net loss of CO2 that will slowly work its way back towards a more natural condition. It will take many years to make it most of the way there, but like an exponetial decay curve (if that model were to resemble the effect) we would never really get back all the way. Of course, the earth is more complex. If we plant and manually sustain more trees (or add other CO2 sinks.. eg, consume CO2 via microorganisms that sequester the result in some chemical form), then we could not only get back to "normal" as defined by today's system but even go beyond it. And then there are planetary effects and basically a bunch of effects (feedbacks) that don't follow the exponential decay model either.
Sorry to not give you a precise answer. You asked in the right place and some studies address that concern. I just wanted to give an idea that what you are asking has nothing to do with this abstract 5 year calculation. -
funglestrumpet at 06:21 AM on 5 October 2013Residence Time and Prof Essenhigh
MA Rodger @ 15
Thanks, that is exactly what I was looking for!
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MA Rodger at 05:39 AM on 5 October 2013Residence Time and Prof Essenhigh
funglestrumpet @14.
Archer 2005 concludes with the following line that may be what you are looking for. (I have edited a little it to make its meaning clearer.)
A better approximation of the lifetime of fossil fuel CO2 for public discussion might be ‘‘300 years, except for 25% of the CO2 that lasts forever." -
funglestrumpet at 04:59 AM on 5 October 2013Residence Time and Prof Essenhigh
HELP!!! Could someone please help a poor confused bloke like me who comes here to help them do battle at the street level on the climate change front (think Daily Mail readers and the like)?
For instance, when 'debating' with a typical denier on the "global warming has stopped" meme, I have tended to use the argument that it takes ages (plus or minus an age or two) for CO2 to fall out of the atmosphere (and sod what Newton might have to say on the topic because apples are a lot heavier than CO2 molecules and thus fall more readily).
It follows that global warming cannot have stopped because the excess CO2 we have pumped into the atmosphere over that last half century or so is still airborne and will be there for a long time yet warming the planet as it does so. Five years is not even near half an age, so what number of years should I use in presenting my case, 5, 50, 75 or what?
I imagine the answer lies in the article somewhere, but it is well hidden from a simpleton like me.
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william5331 at 04:35 AM on 5 October 2013Residence Time and Prof Essenhigh
There is a grain of hope, losely related to Prof. Essenhigh's contentions. Carbon dioxide varies about 7ppm annually or more accurately, 8 up and 6 down. Natural processes remove far more CO2 than any silly system we could devise to sequester Carbon dioxide. Of course we must first stop pouring Carbon dioxide into the atmosphere but then we could give Gaia a chance and restore her systems for removing CO2 to their full potential.
http://mtkass.blogspot.co.nz/2013/03/removing-atmospheric-carbon-dioxide.html
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raywey at 04:23 AM on 5 October 2013Residence Time and Prof Essenhigh
A useful analogy (and a bit closer to the actual situation than the queue) especially here in Caifornia where lots of people have spas and swimming pools:
My pump circulates water into and out of my spa at an input rate of **** (fill in your
favorite number) and removes it at the same rate. But I have taken my garden whose
and added water at a much smaller rate (&&&&). The residence time for any molecule of water in the spa is short compared to the time the hose fills an empty spa, but does anyone think that it is not the hose that is causing the water level in the spa to increase? -
Composer99 at 04:04 AM on 5 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
If that's what Tisdale comes up with as an "only imaginable reason", then I submit that he is admitting to having a very stunted imagination.
Which would be selling himself short: like most "pro/semi-pro" contrarians/deniers, Tisdale actually has a very fertile imagination. (Unfortunately, he has the bad habit of mistaking (or misrepresenting) the fruits thereof for reality.)
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Rob Honeycutt at 03:55 AM on 5 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Let's look at Tisdales opening complaint where he states,
The models presented from the IPCC’s 1st, 2nd and 3rd Assessment Reports are considered obsolete, so the only imaginable reason the IPCC included them was to complicate the graph, redirecting the eye from the fact that the CMIP3/AR4 models performed poorly.
Really? The only imaginable reason? Do you start to wonder why Lewandowski is publishing on conspiracy ideation amoung climate denialists?
So, Tisdale starts off with the assumption that there are no other possible explanations for including FAR, SAR and TAR data. I can offer a simple explanation. How about the idea that they would be criticized if they didn't include them?
I have a hard time fathoming why any half way intelligent person would read beyond this one statement in Tisdale's post, other that just morbid curiosity.
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Rob Honeycutt at 03:42 AM on 5 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Bob... Tisdale randomly dismisses Tamino's point, that was clearly accepted by the IPCC as being correct, that it is not proper to baseline on a single anomalous year.
This is exactly the problem with "leaked" versions of a draft paper. Those who are so mentally inclined, like Tisdale, McIntyre and others, are going to divine nafarious intent where there is none.
Tisdale also lacks the capacity to do actual statistical analysis to show his point, something that Tamino is capable of doing and, in fact, did.
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Bob9499 at 03:16 AM on 5 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Dana, Bob Tisdale comments on your post:
http://wattsupwiththat.com/2013/10/04/no-matter-how-the-cmip5-ipcc-ar5-models-are-presented-they-still-look-bad/
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Albatross at 02:36 AM on 5 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Hi OPatrick,
No worries, we seem to have had a miscommunication. I think that we are on the same page now :)
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OPatrick at 02:29 AM on 5 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Albatross @23 - I never bought it as such in the first place, I just thought that Dana was mistaken to have said Curry had quoted the IPCC discussing the issue in the SPM, when she was actually quoting something which she felt (to be generous) had been left out of the Approved version. As we have both shown the replacement wording is not different enough to justify her criticisms.
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Albatross at 02:20 AM on 5 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Opatrick @19,
The following claim by Curry is demonstrably false:
"Nowhere in the final WG1 Report do we see the honest statement that appeared...."
Please read AR5 WG1 that was released this past Monday. They say, and I quote:
"Most simulations of the historical period do not reproduce the observed reduction in global-mean surface warming trend over the last 10–15 years (see Box TS.3). There is medium confidence that the trend difference between models and observations during 1998–2012 is to a substantial degree caused by internal variability, with possible contributions from forcing inadequacies in models and some models overestimating the response to increasing greenhouse-gas forcing."
Now do you still buy Curry's claim as being correct? I hope not.
You also seem to be missing the point (I noted another problem with Curry's comment in my post @12 above).
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OPatrick at 02:17 AM on 5 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Bob @16 - yes I read it, but having done so fairly quickly I am far from clear of the point she is making. Her ability to communicate her points clearly, other than her opinion of Tamino, is not fantastic.
However, she does say that Tamino is correct to have criticised the draft AR5 WG1 SPM report for incorrectly aligning projections to observations in a single year and then rants about Dana who is quoted having credited Tamino for pointing out what she has just said he was correct about.
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kanspaugh at 02:15 AM on 5 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Could it be that Curry just wants publicity? Thinks the more she's in the news, the better for her consulting business? And, since she can't get much press attention as a climate scientist -- not bright enough -- she'll get it as a contrarian? Could it be, in short, that Judy is all about the Almighty Dollah?
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Albatross at 02:09 AM on 5 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Bob @14,
Oh shame, the spinmeister fake skeptics are upset. Who is "Lucia"? Oh right, another contrarian who likes to argue and nit pick to distract while missing the bigger picture. I doubt very much that Tamio is wrong-- let me see, Tamino who is professional statistician (who has actually pubished peer-reviewed climate papers) versus a "skeptic" mechanical engineer.
Lucia is arguing semantics, white noise. Before you get too excited please also read my post @12, Curry et al. are wrong on sooo many levels ;)
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OPatrick at 02:08 AM on 5 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
dana @10 - Curry's claim was:
Nowhere in the final WG1 Report do we see the honest statement that appeared in the Final Draft of the SPM:“Models do not generally reproduce the observed reduction in surface warming trend over the last 10 –15 years.”
It seems to be true that the wording has changed from the Final Draft to the Approved SPM. The first paragraph of the final draft section on Evaluation of Climate Models begins with:
There is very high confidence that models reproduce the more rapid warming in the second half of the 20th century, and the cooling immediately following large volcanic eruptions. Models do not generally reproduce the observed reduction in surface warming trend over the last 10–15 years.
Whilst the Approved version has
The long-term climate model simulations show a trend in global-mean surface temperature from 1951 to 2012 that agrees with the observed trend (very high confidence). There are, however, differences between simulated and observed trends over periods as short as 10 to 15 years (e.g., 1998 to 2012).
The highlighted sentences (my bold) do not seem far enough apart to justify her implication of a lack of honesty.
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dana1981 at 02:08 AM on 5 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Nor, by the way, is Lucia's anal semantics nitpicking applicable to anything in the above post, by the way.
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dana1981 at 02:07 AM on 5 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Bob @14 - I hope your comment was intended as a joke. If not, you either didn't read or didn't understand the above post. As I said, IPCC Figure 1.4 is baselined using the period 1961–1990. Lucia is just being anal (which is what she does best) about the language Tamino used in his post, and her criticisms are not remotely applicable to AR5 Figure 1.4.
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Bob9499 at 02:02 AM on 5 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Opatrick, have you read Lucia's post, or was yours just a knee jerk reaction.
Moderator Response:[RH] Bob, please note that this is not WUWT or Lucia's place or Curry's blog. There are clear standards for posting here. Please read them before continuing on. Everyone here is willing to discuss the issue but you're going to have to conduct yourself in a professional manner.
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OPatrick at 01:58 AM on 5 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Bob @14 - you appear to have a different understanding of the meanings of the words 'destroy' and 'clear' from me, at least.
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Bob9499 at 01:48 AM on 5 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Lucia just destroyed your post and clearly demonstrated why Tamino is wrong.
http://rankexploits.com/musings/2013/taminos-take-on-figure-1-5/
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Albatross at 01:14 AM on 5 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Hi Chris @11,
Well yes of course, but you seem to be missing couple of key points:
1) Generating thes complex graphics takes time and to get it right almost always requires several iterations. To expect otherwise is just not being reasonable.
2) Keeping #1 in mind, note that the draft figure was stolen/leaked (probably by fake skeptic) almost a year before the release of AR5. So it is not surpring that it had a glitch.
The lesson to be learned here Chris is that one simply cannot trust fake skeptics to act in good faith or with good intentions. They will mislead and misinform at every opportunity. As a case in point, ompare for example how statistician Tamino dealt with the situation when it was brought to his attention, compared to say how McKitrick and McIntyre and Curry dealt with the situation.
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Albatross at 01:04 AM on 5 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Judith Curry exposed
Dana very nicely covered just how wrong Curry et al. are in their (biased) opinions. However, believe-it-or-not the reality is actually much worse for Curry.
Curry is of the opinion that climate models do not help her understand climate. A bizarre thing to claim for three reasons:
1) William Connolley calls out Curry on her double standard. He notes:
"...if you write a paper in which “the model simulations … were the main source of data used in the analysis” and yet you don’t think the models help, you’re not really going to write anything sane".
Exactly. Well, why does she bother using them for her research then? The truth, as we know, is that all models are wrong, but they are still incredibly useful tools. Curry is being disingenuous.
2) It gets worse though. Curry and her husband Peter Webster run a consulting company called "Climate Forecast Applications Network (CFAN)". Think about that name, what it indicates they do and then try and reconcile it with Curry's musings about climate models. From the CFAN web-site (my bolding):
"CFAN can transform future climate scenarios into meaningful information for your organization."
Those "future climate scnerious" are undoubtably based (at some level) on output from climate models developed and run by agencies that also provided their model output for inclusion in the IPCC assessment reports.
Curry also assures their clients that:
"CFAN's approach to developing future climate scenarios provides the basis for assessing future risk to your organization, as well as for identifying future opportunities."
So Curry is promising all kinds of deliverables based on the very climate models that she claims are "wrong". How bizarre.
3) Now for the pièce de résistance. This one is more subtle but every bit as egregious.
Again from the CFAN web site (my bolding):
"CFAN's weather and climate predictions, spanning time scales from days to decades, are based upon a sophisticated statistical/dynamical system that utilizes ensemble forecasts from multiple weather and climate modeling centers."
Producing decadal forecasts is notoriously difficult. As Dana mentioned above and as Curry also concedes, current climate models struggle on the decadal scale (for reasons that I won't go into here). But riddle me this. Curry is entrusting her business (and income) on the very models that she claims are wrong. What is more, she is trying to claim the models are wrong period by using data on a decadal time frame (full well knowing that they struggle on such time scales), but at the same time is informing CFAN clients that they can provide forecasts on a decadal time scale. Her duplicity is just astounding!
Curry wants to have it both ways. She wants to play rhetorical denier games in the public eye, and she also wants to derive income from the very models that she alledges are wrong.
CFAN clients and graduate students (present and prospective) should find these revelations more than a little disconcerting. She is misleading more than one group of people here.
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ChrisRapley3131 at 01:02 AM on 5 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
On an issue so sensitive as this it would have been a whole lot better if the figure had been produced correctly in the first place. Mistakes get made and that's real life - but on this particular graph and in this particular way - there is a lesson to learn, surely?
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dana1981 at 00:20 AM on 5 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
OPatrick @8 - that may have been what she meant, but it's not what she said. The fact that the folks working on the SPM went out of their way to address this relatively trivial issue just because so many contrarians were making noise about it, and she's still complaining that they didn't adequately address it, says a lot.
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IPCC model global warming projections have done much better than you think
Sereniac - I am personally quite wary of extended analogies. A simple analogy between a portion of a complex system and a more commonly known system may be helpful in explaining how that part of the relationship acts, but the larger and more complex the analogy the more likely it is that the reader will mis-extrapolate from it, attempting to argue back from that analogy to the complex system.
Analogies are not the original, and commonly understood relationships in the analogy may or may not map back to the complex system.
In terms of the actual climate system: ENSO variations change the Pacific ocean circulation. Sunlight comes into the climate, warms the oceans and atmosphere, and is radiated away to space - input and output. ENSO variation affect how that energy behaves when it is in the climate system.
A La Nina, with higher wind-driven exchange of deep cooler water, moves a greater portion of that incoming solar energy into the oceans, cooling the atmosphere by ~0.1 C. An El Nino reduces the deep circulation, reducing energy flow into the oceans, causing that energy to remain in the atmosphere and warm it by ~0.1 C. It's really that simple.
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Leto at 23:33 PM on 4 October 2013IPCC model global warming projections have done much better than you think
Sereniac,
The problem I have with that analogy is that the fitness training is not just a distractor that hides the true fitness signal, it leads to genuine improvements in fitness. The ENSO fluctuations do not lead to analagous true improvements in the global heat balance.
What if your Mr Jones is becoming morbidly obese, and this can be accurately projected using a metabolic model, but his measured weight flucutates in the short term by as much as a 2kg (eating 2kg donuts, as he does at random times, inflates his apparent weight by 2kg).
He visits the doctor immediately after a donut splurge, and posts a record weight (c.f. 1998 el nino). He then continues to eat excessively, but 15 days later, his next weight assessment happens to be just prior to his daily donut splurge. He has actually gained 1.5kg in weight, and is now posting a record empty weight (c.f. recent record la nina), but his measured weight is 0.5kg lower than the last measurement. He boasts that his weight trend is going down, and declares the doctor's metabolic model to be bogus. On the contrary, he is fatter than ever, and his next post-splurge weight is expected to break all records (c.f. next significant el nino).
A plot of his post-splurge measurements shows no overall change in the post-splurge trend, as does a plot of his pre-splurge weights (c.f the separate el nino and la nina trends in the Neilson-Gammon plot), but the short term fluctuations in apparent weight mean that he often has pseudo-pauses in his relentless weight gain. The existence of such pseudo-pauses is entirely expected in the metabolic model, though the timing of the pauses is outside the scope of the model, and an ensemble of model runs will average out the pauses so that they are not apparent. Nonetheless, he uses the pauses as an excuse to continue his unhealthy lifestyle.
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bouke at 22:48 PM on 4 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Thanks for the replies @5-7. Inspired by Kevins remark, I googled around some and found a nice explanation at the American Chemical Society.
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OPatrick at 22:27 PM on 4 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
This is an odd statement, given that Curry had earlier quoted the IPCC discussing this issue prominently in its Summary for Policymakers:
"Models do not generally reproduce the observed reduction in surface warming trend over the last 10 –15 years."
Wasn't her point that this quote did not appear in the WG1 report?
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Glenn Tamblyn at 22:01 PM on 4 October 2013IPCC model global warming projections have done much better than you think
Interesting analogy Sereniac. One thing missing from it is the quantitave apart from words like 'dramatically'.
Lets epand the analogy by saying the Mr Jones health indicators tend to rise by X when he trains for a fun run and decline by Y when has allergies. And his glucose problems cause a decline of Z per year. So how easy is it to detect Z in amongst X and Y? That depends on the relative magnitude of X, Y & Z.
If X and Y are small, Z can be detected quickly. If they are larger, Z takes much longer to detect.
Back to the ENSO issue. El Nino (X) and La Nina (Y) produce effects that can change average temperatures by +/- 0.1 to 0.2 Deg. This can mask global warming (Z) on time scales of a decade or so. But on multiple decades to a century, where global warming might cause temperature changes of 2-4 DegC (depending on what we do with emissions) then Z becomes very clear.
Mr Jones' glucose problems become apparent when he can't engage in his training for the fun run because he is hobbling along with a cane.
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Dikran Marsupial at 20:47 PM on 4 October 2013Residence Time and Prof Essenhigh
chriskoz Essenhigh's 5 year figure for residence time is correct, and indeed agrees with the figure given in the IPCC WG1 report. His error lies in not understanding the distinction between residence time and adjustment time.
We should not be too hard on Prof. Essenhigh, his research record in his own field (combustion) appears to be very good, and it is all too easy to make this kind of error in moving into a tangentially related field. The email correspondence I had with Prof. Essenhigh while writing my response published in Energy & Fuels was generally very cordial.
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chriskoz at 19:56 PM on 4 October 2013Residence Time and Prof Essenhigh
Essenhigh's 5y residence time number is bogus not only because it fails to consider the natural inflow (emissions from ocean/biosphere back to atmosphere) but also because, due to limited capacities of the natural sink such as ocean, the flow rates (determined by Henry's law) change over time.
Only a part of CO2 molecules has a residence time of rougly 100y (a bit more than 75y calculated by vmin@8 but the same ballpark). In case of 1000GtC emissions, that part is some 50% - i.e. 500GtC of the original emissions being absorbed by the ocean surface results in OA reaching new equilibrium, therefore no more CO2 can be absorbed by Henry's law.
The rest (500GtC) must wait for the deep water mixing and the reaction with sediments which takes 1-10Ky. Only 300-400GtC is taken that way, again due to limited sediment capacity.
The rest (100-200GtC) must wait for the rock weathering processes which take sometime from 100Ky to 500ky (depending on current geological conditions).
So, the residence time is not a simple constant number when we are dealing with such big amounts comparable to the natural sink capacity. In case of the emission scenarios considered in Anthropocene, it means 10 to 20% of emissions will stay in A for up to half a million years.
Obviously, such science is well beyond Essenhigh, who makes very basic mistakes (i.e. ignores the inflow & Henry's law) that preclude any understanding of carbon cycle in geological sense.
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Kevin C at 19:55 PM on 4 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
It's also worth noting that land-ocean surface temperature records work with anomalies rather than temperatures, and thus they don't provide an absolute temperature against which to compare the models.
BEST have addressed this, but their currently released data is land-only.
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Dikran Marsupial at 19:29 PM on 4 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
bouke, it is because the models do a much better job of modelling changes in response to forcings than in terms of absolute temperature (i.e. there are more or less constant offsets in absolute temperature between model runs). For climate change research it is the response to a change in the forcings that is of interest, so the simplest thing to do is to apply the baselining procedure to eliminate these meaningless offsets. Note also that if you want to perform a comparison involving both surface and satelite observations you have to look at the anomalies anyway as there is a big difference between absolute temperature at the surface and in the trophosphere due to the lapse rate.
This is something well known to any climatologist that has worked with model output and is essentially uncontraversial, so it is somewhat surprsing that Curry and McIntyre are making a fuss about it.
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Dikran Marsupial at 19:23 PM on 4 October 2013Residence Time and Prof Essenhigh
vmin Residence time is defined as the mean length of time a molecule of CO2 remains in the atmosphere before being taken up by the terrestrial or oceanic reservoirs, so Essenhigh is correct in using the term residence time. His error lies in not understanding the difference between residence time and adjustment time, which is the characteristic timescale with which the atmospheric concentration responds to a change in sources and sinks (which corresponds to your 75 year figure). The IPCC define these differing definitions of lifetime in the glossary of the WG1 report, but unfortunately do not clearly distinguish between them in the report itself (although the 1990 report that Essenhigh cites makes the distinction very clearly).
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Marco at 19:12 PM on 4 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Bouke, it is not about the vertical scaling, but about what point you use as a reference. 1990 as a single point is a bad reference, as it would be above the trendline. 1991 would be a bad point, too, as it is below the trendline. You should use a baseline *period*, which will eliminate much of the short-term noise. Whether you put that baseline as an absolute value or assing it to zero and put the other data as anomalies does not change any conclusions.
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bouke at 18:39 PM on 4 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
I am wondering, why are graphs always shown with temperature anomalies and not with the actual temperatures? That should remove any confusion with baselines.
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PJKs_shirt at 16:15 PM on 4 October 2013Skeptical Science now an Android app
Any chance of porting the app to Sailfish?
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sereniac at 15:46 PM on 4 October 2013IPCC model global warming projections have done much better than you think
I've been trying to construct a layman's interpretation of the role of ENSO in AGW and came up with the following.
Apologies for the level it is pitched at, but I'm grasping for a conceptual framework
that most people can understand so that there is a better appreciation of the difficulties involved.Thanks for any feedback.
__________________________________________________________________________
A group of researchers only has access to a single individual: Mr Jones.
The researchers are interested the phenomenon of aerobic fitness in Mr Jones and have a number of measures: resting heart rate and blood pressure, weight and BMI and time to complete a 5km treadmill run. Note that Mr. Jones is the only source of data and these measures can be obtained at any time, but there are no other research subjects.
At the end of each year the average fitness of Mr. Jones is calculated as a combination of mean resting HR, BP and treadmill time.
The researchers notice that Mr Jones has started consuming greater and greater quantities of drinks that are high in glucose. They are concerned that he will ultimately exhibit weight gain and loss of fitness even if the drinks may initially provide a short term energy boost when drunk. With weight gain comes obesity and chronic diseases.
Hence the hypothesis is that excess glucose consumption will manifest itself as a decline in average aerobic fitness and especially weight gain/BMI, increases in resting HR and BP. If this is not avoided then chronic diseases such as diabetes, heart disease etc could be evidenced in another 30 or 40 years. That is the scenario to be avoided.
It is a simple matter to measure Mr Jones’ annual aerobic fitness and as he continues to consume more glucose over say 15 years, his fitness appears to decline. Projecting this decline into the future suggests that in 30 years Mr. Jones will be obese, chronically unfit and with dangerous levels of BP.
However, Mr Jones is also invited to a fun run about every 1-2 years. Mr Jones undertakes a serious course of training for each of these runs which vary in their distance and calendar timing. The runs can take any distance between 5km and 15km and although the runs happen roughly around the same time they can be advanced or delayed by many months. Hence the intensity and length of the training cannot be predicted. But whenever Mr. Jones trains, his aerobic fitness dramatically improves. This fitness also lasts quite a while after the fun run.
On the other hand, Mr Jones is also sometimes affected by severe allergies. When this happens his activity levels drop dramatically. He can spend months doing very little at all and this diminishes his aerobic fitness a great deal. The timing of these allergies is roughly seasonal, but can happen early or late and in some years the allergies do not appear at all. In addition, while some years are very bad for his allergies, in some years they are evident, but quite mild. In short, Mr. Jones’ allergy reactions are roughly periodic but still unpredictable in timing and intensity.
The task before us is projecting Mr. Jones fitness 30 years into the future when there is an evident trend of fitness decline with an increasing consumption of glucose drinks despite the fact that (a) Mr Jones fitness can improve from fun run training and (b) it can decline from allergies yet both cannot happen at the same time.
Consider the situation where Mr. Jones appears not to be getting less fit yet over the same period he has been invited to a number of very long fun runs which required a lot of training. Can we still be confident that glucose is driving a loss of fitness?
Also consider the situation where Mr Jones has shown a rapid loss of fitness but over the same period he has had a number of long and intense allergic reactions. Can we likewise be confident that glucose is driving the loss of fitness or is it just the effects of allergies?
The situation is further complicated because Mr Jones is the only source of data. We cannot obtain information on the general role of excessive glucose consumption by measuring other people (they do not exist). Bu that would be very useful because the influence of fun runs and allergies would be more easily quantified- we would have varying timing and intensity of these influences on the fitness of many people rather than just one.
These are some of the issues involved in projecting climate on the only planet
you have. -
One Planet Only Forever at 15:07 PM on 4 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
It should be possible to statistically prove that the contrarians "conspire" to coordinate their "cross-selling". The tendency for them to mainly refer to claims made by each other could be evaluated statistically. This would then be evidence of their "conspiracy to misinform" by adding the evaluation of the validity of the claims they make and "cross-sell".
The scam of using one person to say something that is then referred to by others as "proof" of something is even used by media groups like Fox News which will have one of their "speculators" say something then have their "News People" repeat the claim but frame it as something that "people are saying", when the only ones saynig it are the ones inside their operation hopng to get "others to say it".
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TonyW at 13:56 PM on 4 October 2013Lawson, Climate Change and the Power of Wishful Thinking
Lawson is an idiot. What a shame, though, that his last sentence is almost certainly true (with high confidence). -
Tom Curtis at 13:52 PM on 4 October 2013CO2 is just a trace gas
Bob Loblaw @16, your definition is non-standard.
The best definition of the atmospheric greenhouse effect is the difference in upward longwave radiation at the TOA to that at the surface due to absorption and emission of longwave radiation be components of the atmosphere.
Based on that definition, clouds contribute approximately 25% of the total current greenhouse effect, coming in behind water vapour (50%) but ahead of CO2 (20%). (See link in my post responding to Undecided Molecular Biologist above.)
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Tom Curtis at 13:47 PM on 4 October 2013CO2 is just a trace gas
Undecided Molecular Biologist @5 & 8, here is a spectrum of infrared radiation to space at the Top of the Atmosphere as calculated by the Modtran Model:
The important points are:
1) The Earth's TOA black body radiation without a greenhouse effect would follow the shape of the coloured lines (black body radiation curves), with the specific shape depending on surface temperature;
2) The absorption of IR radiation from the below, and reemission at a higher cooler altitude results in a reduction in the TOA outgoing radiation, by the amount shown by the red shading;
3) The largest single factor in that reduction is H2O with absorption and reemission at wave numbers less than 550 and greater than 1300 (the initial dip around 1250 is due to methane);
4) The second largest single factor in that reduction is that due to CO2 at a wave number of about 650;
5) The reduction to CO2 is almost as large as that due to H2O in a clear sky;
6) Although there is some overlap of H2O absorption and CO2 absorption, because CO2 is higher in the sky (as can be seen by its lower temperature of emission), it would have the same effect even in the absence of the H2O, so that the H2O has no effect in areas of overlap; and
7) The large CO2 absorption band is located near the peak of terrestial emissions allowing it to have a much larger impact than other absorbers.
Modtran is only a model, so you may be disinterested in what it shows. Such models have been compared with observations, however, and shown to be remarkably accurate. An early such comparison was published in 1969:
These and similar observations show that your parade of "corrects" are based on prejudicial thinking rather than on actually looking at the observational data on the issue. Absent such prejudicial reasoning, it can be discovered that CO2 is responsible for approximately 20% of the all sky greenhouse effect.
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Tom Curtis at 13:01 PM on 4 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
1) I believe that figure 2 (the trend comparison) would be improved by also showing the AR4 trend, using observed data for the years 1990-2000 (as AR4 projections start in 2001).
2) McKittrick did worse than simply eyeballing the trends. Anybody with any experience in eyeballing trends could see from the draft figure that the trend for observations (and of AR4 plus observations from 1990-2000) would pass well below the 1990 point in the observations due to the large temperature excursion due to the Mount Pinatubo erruption. In fact, had the draft report baselined the graph by ensuring all trends passed through the same point in 1990 (a perfectly reasonable procedure), that would have lifted the observations relative to the FAR, SAR, and TAR projections. Indeed, sufficiently to place them in the upper half of TAR projections (from my eyeball estimate). It would not have significantly shifted the them relative to an observations to 2000 plus AR4 due to the shared initial data.
Because much of this shift would be due to the Mount Pinatubo erruption, that may seem like an unfair comparison. To avoid that, the proper method is to use an extended baseline, as above, or to set the data for a common origin of trends having adjusted the data for short term factors not expected effect the long term trend, ie, something like this:
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sereniac at 12:44 PM on 4 October 2013IPCC model global warming projections have done much better than you think
Thanks Bob.
Unfortunately it is possible to obfuscate even the basic science unless it is codified in some form and the essential assumptions are clearly documented in a paper or analysis.
For example, it is now required that all randomised control studies and other research reveal their power calculations as part of journal submissions. There are a number of assumptions underlying that as well and they can be questioned but it helps to quickly terminate papers that have insufficient statistical power to address the null hypothesis.
I maybe naive because the depth of "declaration" of what is being assumed could
include euclidean geometry being correct, but at least amongst the sophisticated
scientists grappling with core issues, there could be a higher level and more
explicit level of declared assumptions. And there could at least be a declared
concensus or manifesto if you like of what are unchallengeable assumption underlying analyses.I am at least able to conduct a basic MLR and understand the judgements that
apply, but it appears to me that in in addition to statistical treatment decisions, climate science often has very basic processes routinely questioned by people with
the undergraduate (at least) training to know or know better.It is very confusing for outsiders in any field to judge the validity of arguments when credentialled people claim widely disparate conclusions based on very or mildly disparate assumptions.
I really don't expect to read a paper where the mixing depth of oceans is disputed anymore than I expect a physicist to dispute the molecular weight of carbon or
at least within agreed bounds.
Thanks again. -
mikeh1 at 12:39 PM on 4 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Ross McKitrick brilliant? I do not think so.
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Bob Loblaw at 11:57 AM on 4 October 2013IPCC model global warming projections have done much better than you think
sereniac: "there has not been open and transparent declaration and agreement on the basic assumptions behind basic positions."
As you learn more, you will tend to find the following:
- on what I will call the science side, there is pretty strong agreement about many of the basic assumptions. After all, a lot of the basics were worked out in the 1800s. (Yes, that is the 1800s. Not a typo.) For a look at this history, try this link. Scientists usually don't spend a lot of time discussing the basics that were agreed upon over 100 years ago. You learn them as an undergard, and move on.
- on what I will call the "skeptics" side (although they are clearly not true skeptics), you will discover many mutally contradictory assumptions, which change with the shifting wind. They will assume whatever will lead to the conclusion they want, and then assume the opposite in another situation. Consistency is not a priority. If you follow the Arguments menu below the Skeptical Science masthead (at the top of every SkS page) to the Contradictions page, you'll end up here, where many of the "skeptical" contradictions are listed. The "skeptics" can't even agree amongst themselves what the basic assumptions are, let alone agree with the scientists.
I take that back: the "skeptics" do have one fundamental assumption that is constant behind every argument: that the climate science is wrong. Everything else is malleable to fit that assumption.
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sereniac at 11:24 AM on 4 October 2013IPCC model global warming projections have done much better than you think
Thanks for the Loehle/Scafetta critique.
I have to confess that I really believe that a huge amount of the animosity and confusion associated with the AGW issue arises because there has not been open and transparent declaration and agreement on the basic assumptions behind basic positions.
It is extremely frustrating for everyone to burrow through analyses only to find what SHOULD be a known physical fact being disputed e.g. depths of ocean mixing or whatever. Or CO2 solubility or whatever.
I don't attribute blame disproportionatley here and it seems to me that all sides would achieve clarity and progress if these fundamentals were agreed to in some manifesto.
That would at least provide a focal point where analyses could be dismissed outright because they did not adhere to assumption 3.4.3.1(a) or whatever.
I realise this would be very contentious exercise in itself and some would argue just as much work as the IPCC itself, but I have to be candid, as an outsider it is somewhat like reading an orbital calculation where the altitude of the orbit is in dispute because of differences in judgements of what "counts" for the height of Everest.
It's not just silly. It's ridiculous.
Scientists should be able to reject that orbit because the height of Everest is agreed
to be Xmm plus or minus whatever due to thermal expansions, storms or whatever.
Really this seems to have become the ultimate case of apples and oranges.
Sorry if I come across as frustrated- I'm sure many of you are as well and possibly
exhausted by the number of apples you see counted as oranges.
But truly, science just cannot progress efficiently without a clear declaration and
agreement of (a) what is known and (b) what is assumed in the science of climate. Doing so must decrease the statistical uncertainties involved.
I shall go back inside my box.
Thanks again
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