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“Even if we cannot definitively attribute a climate change link to a specific event does not mean that we can’t discuss how climate change is likely to impact such events and whether or not we’re seeing changes that are consistent with what is expected.”
Leads to a degree of confirmation bias.
If every extreme event is expected to occur with greater frequency then the mere occurrence of any said extreme event becomes automatic proof of your position, making it a definite attribution.
Seems wrong on some level even if right.
Nothing wrong with talking about the expectation
“Climate change is clearly happening and it is mainly driven by our emission of greenhouse gases (mostly CO2) into the atmosphere. Doing so causes atmospheric CO2 to increase, reducing the outgoing energy flux and causing energy to accumulate in the climate system. This will lead to warming of the surface and troposphere, increasing ocean heat content (and increasing sea surface temperatues), an increase in evaporation, an increase in the frequency and intensity of extreme precipitation events, and a change in the latitudonal temperature gradient that has the potential to influence the jet stream and, hence, weather patterns. This means that in regions that are susceptible to extreme weather events, the conditions will increasingly tend to favour these events becoming more extreme.”
But extreme events have to be rare and rare events are difficult to pin causation on and even a 5% increase is perfectly acceptable within a normal range. As well as fitting an expectation.
It is an argument that can lead to calls of crying wolf.
Wolves are out there but no-one appreciates calls that are not definitely attributable.

• ngech says:

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  September 6, 2018 at 3:34 am

  Thanks Izen for mentioning a sensible time scale environment.
  Andrew, I don’t understand or do not want to believe or do not get it.
  Your change in temperature for a x4 inst. forcing only goes up very slowly, years in fact to perhaps get to 2 C, then much longer to get higher [ATTP’s centuries+ to get to an equilibrium].
  I want to believe that an atmosphere with a x4 increase in CO2 [and maintained there thereafter] must have a new temperature very close to the maximum achievable and fairly instantly. like within 36 hours.
  I am prepared reluctantly to accept some lapse as the change in heating permeates to its final level. Perhaps a different simpler picture of a non rotating earth would help the imagery. Here the retained incoming heat would rapidly build up and then spread to the dark side over time, hours days until the outgoing again balances the incoming. Obviously some heat would be transferred/ building in the oceans. But this again could balance fairly soon. The oceans being hotter on the surface keep the air warmer and decrease rapidly the amount of heat needed to be put in to achieve that balance as well.
  My point, dense though it is, is that a volume of gas of known composition, on a known backdrop of water/land on one side, space on the other, heated by a known income source [np clouds] has a known expected scientific temperature.
  Earth at 500 ppm CO2 , Earth at 2000 ppm, each has a set expected temp [specifiable in a range if not exact]
  I realise that ocean temperatures can take months to vary but atmospheres are much thinner and reactive. 0 at night to 30C in the day at Alice Springs. Why should not the temperature reaction of a known composition adjust to that expected temperature, or close to. more quickly?
• angech says:

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  September 6, 2018 at 4:33 am

  Steven, “attack the pattern argument”
  I read AD An Estimate of Equilibrium Climate Sensitivity From Interannual Variability
  “It is also worth stepping back and asking what could cause our calculation to be seriously in error.
  It seems unlikely that forcing from doubled CO2 is wrong given our good understanding of the physics of CO2 forcing (e.g.,Feldman et al., 2015).

  Estimates of ? iv,obs and ?iv,obs are derived from observations we view to be reliable,
  so our judgment is that they are also unlikely to be significantly wrong.

  The ?TS/?TA factor comes from climate model simulations, but models have long been able to accurately reproduce the observed pattern of surface warming (e.g., Stouffer & Manabe, 2017), and we have simple physical arguments explaining how the atmospheric and surface temperature should be connected (Xu & Emanuel, 1989).
  Finally, we can compare the models to data (Compo et al., 2011; Poli et al., 2016) to validate their simulation of this ratio.

  Thus, the transfer function seems the most probable place for a significant error to occur. We also argue that while errors may exist in a model (i.e., in the cloud feedback), this will affect both the numerator and denominator and such errors will tend to cancel out.
  While one must be careful about conclusions based on a single model, this nevertheless provides some support for the hypothesis that errors in ? 4xCO2
  will cancel errors in ? iv when the ratio is taken.

  As a preliminary test of this, we have analyzed three different versions of the MPI-ESM 1.2 model that have had their cloud feedbacks modified to produce different ECS (Thorsten Mauritsen and Diego Jimenez, personal communication, 2018). The three versions are the standard model (ECS calculated from an abrupt 4xCO2 run using the Gregory method = 3.0 K), an iris version (described in Mauritsen & Stevens, 2015; ECS = 2.6 K), and a high ECS version, in which the convective parameterization has been tweaked to generate a large, positive cloud feedback (ECS = 5.2 K). ”
  –
  I have cut, pasted and tweaked this somewhat, apologies for those bits left out. It contains numerous items relevant to past discussions on this and other blogs supportive of some of my past statements.
  I have trouble understanding “if the argument turns on which version of ice is used,”
  So I am probably cross discussing..
  Here, with Andy, He has outlined his procedures well. He believes ” models have long been able to accurately reproduce the observed pattern of surface warming ”
  I would argue that reproduction is different to predication, I would hope the models do accurately reproduce. any argument that observations could be put aside when they disagree with the reality of models is fraught. though not untenable.
• angech says:

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  September 6, 2018 at 4:58 am

  I have trouble understanding “if the argument turns on which version of ice is used,”
  Time scales as we both know are very relevant to the accuracy of prediction and expectation. When I argue from a very few years of ice increase from one data set you are more than entitled to laugh at me, and others. When the ice sets [satellites] are of short duration 40 years themselves then the laughter should be stifled though the message is still with the long term trend.
  I have no beef with people having beliefs or predictions. Only sticking to legitimate scientific methods. PIOMAS is currently creating some issues for people wanting warming. They believe it is not accurate now though they were happy to accept it while it was falling precipitously. Skeptics did not believe it when it was falling. Both cut from the same cloth.

dikranmarsupial says:
August 17, 2018 at 6:56 am

angech wrote “ECS can only ever come out as it is programmed in. ”

This is just grade A bullshit. If I were a Magrathean and built a replica Earth (as indeed they did), it would have the same ECS as the real Earth because it is an emergent property of the physics governing climate (and the position of the planet in the solar system and the distribution of land masses etc.), not because the Magratheans “programmed it in”. It doesn’t make any difference whether you simulate that physics on a computer (supposing you could do so with infinite spatial and temporal resolution) or whether you simulated them using a replica Earth.

It is the constant stream of this kind of bullshit (and angech is not the only one) that means I am giving up on commenting on blogs, probably permanently. As a scientist, I feel a pressure to respond to this sort of incorrect assertion about science, but at the same time I know it is a complete waste of my time because angech (an others like him) will continue to spread the same bullshit elsewhere or here in a later thread, or move on to some other topic of bullshit. Thus I can’t enjoy just having a reasonable discussion here on a topic I find interesting without being bothered by bullshitters every time (and I mean every time). It appears I should probably stop reading blogs as well. Well done angech.
dikranmarsupial says:
August 17, 2018 at 7:00 am

I should add, it is very easy to show that ECS is not programmed in to climate models. If this were possible, then climate skeptics would just take the code for an existing GCM and twiddle with the parameters etc. until they got a GCM that explains past climate with a low ECS. The trouble is that can’t be done without using parameter values that are either inconsistent with physics or with experiment. Of course this is something that has been pointed out repeatedly over the years. Still waiting.
angech says:
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August 17, 2018 at 10:03 am

angech wrote “ECS can only ever come out as it is programmed in. ”This is just grade A bullshit.”
One could look at 1000 papers like this. They show that ECS outcome, high or low, is very dependent on what initial parameters are put in.
Re examining the Relationship between Climate Sensitivity and the Southern
Hemisphere Radiation Budget in CMIP Models JOHN T. FASULLO
National Center for Atmospheric Research, Boulder, Colorado 8 January 2015
models with the highest values of ECS strongly reduce low-level marine clouds in most regions of the subtropics as CO2 increases, whereas models with the lowest values of ECS actually increase low-level marine clouds in some subtropical regions
The trade-off between a better representation of present-day Southern Ocean or subtropical shortwave CRE in these subsets of models points to choices made in the model development process, rather than robust physical processes. [1]
Consequently, we find no clear physical reason to expect a linkage between subtropical cloud biases and the correlations between ECS and present-day biases over the Southern Ocean.
Instead, the linkage between subtropical and mid-latitude cloud properties is likely an artifact of choices made in model parameterization and tuning [2]
Identifying large model biases in fields physically linked to climate feedbacks remains a promising path for improving models and for potentially narrowing their spread in ECS.[3]
when the correlation between ECS and a present-day climate property arises from a systematic model bias rather than from a real physical process, its utility becomes
questionable [4]
angech says:
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August 17, 2018 at 10:22 am

…and Then There’s Physics says:
angech, You’re just doubling down now. ECS is an emergent property of models.
From RealClimate “Each of these numbers is an ’emergent’ property of the climate system – i.e. something that is affected by many different processes and interactions, and isn’t simply derived just based on knowledge of a small-scale process”
–
“The wording is one issue that I am immediately defeated on. Of course anything that comes out of running a computer program can be said to emerge from it. ” I had this discussion at Lucia’s two years ago with no success. The word emergent is used by many including those promoting the ECS from models view as being an unknown that emerges from the model results. That is it could not be predicted beforehand and yet would fall somewhere in the predicted range.”
–
I feel helpless at this, caught in a paradox. Either we can discuss ideas and be allowed to be wrong but have it explained [I don’t mind being castigated for not understanding] or we can choose to dismiss contradictory views out of hand. Science depends on being explainable. To just say something is emergent means we cannot explain it. In which case what is the point of developing a computer model in the first place if the answer was unprovable?
–
The wording is one issue that I am immediately defeated on.

Joshua.
Sorry about the circles.
Very well put.
“two people can have viewpoints that are mutually exclusive, where both are right”
Godel?
“In this case, we could say that ECS is the function specific inputs chosen by coders, and as such, those coders determine the final value by making choices among specific inputs. Or, we could say that the coders are putting in values that represent our best understanding of physics, and that ECS emerges as an output. Essentially, those views are incompatible, and yet I think both are true.”
You can say both those things.
Some people do.
“You can get anything you like out of a model. If you set it up with scientifically based suppositions about the physics of clouds, based on the existing evidence, and reflective of a scientifically quantified range of uncertainty, they will produce an ECS output range, which likewise reflects a quantified range of uncertainty. This will at some point in the future be modified with scientific improvements.”
is fine.
Note ECS may well be 3 or 4 and better provable and models in the future will, in their arcane way, be the best way of determining it. They must be in the ball park probably inside the bases.
Just they are striking out on the nature pitches.
“You can get anything you like out of a model depending on what you put into it” would be the best interpretation of what I was saying, which I think should be evident yet English is such difficult beast.
“You can only get out of a model what you put into it” is what people here are hearing me say.
Both statements are the same yet mutually contradictory.
Perhaps Willard could explain how this is allowed to happen.
Or ATTP could do a post.

This is the money quote.
IPCC 2007
“These studies highlight some common biases in the simulation of clouds by current models (e.g., Zhang et al., 2005). This includes the over-prediction of optically thick clouds and the under-prediction of optically thin low and middle-top clouds. However, uncertainties remain in the observational determination of the relative amounts of the different cloud types (Chang and Li, 2005). For mid-latitudes, these biases have been interpreted as the consequence of the coarse resolution of climate GCMs and their resulting inability to simulate the right strength of ageostrophic circulations (Bauer and Del Genio, 2006) and the right amount of sub-grid scale variability (Gordon et al., 2005). Although the errors in the simulation of the different cloud types may eventually compensate and lead to a prediction of the mean CRF in agreement with observations (see Section 8.3), they cast doubts on the reliability of the model cloud feedbacks. For instance, given the nonlinear dependence of cloud albedo on cloud optical depth, the overestimate of the cloud optical thickness implies that a change in cloud optical depth, even of the right sign and magnitude, would produce a too small radiative signature. Similarly, the under-prediction of low- and mid-level clouds presumably affects the magnitude of the radiative response to climate warming in the widespread regions of subsidence. Modelling assumptions controlling the cloud water phase (liquid, ice or mixed) are known to be critical for the prediction of climate sensitivity.”
There is more. I truncate only to get a readable comment in. As I recall, possibly from Soden somewhere different models arbitrarily choose a range for absorbtion in thes clouds which can be double another model. I hope most people would agree a doubling or halving gives critically different results and quite a different but predictable emergent ECS.
This is where the input that later forms the ECS occurs.
Worse it implies that 2 wrong assumptions may be being made that somehow compensate each other in that they then produce the right ECS.

an article on climate uncertainty and risk.

The first issue with uncertainty and risk is with adequate, meaningful data.

We do not have this at this stage. We need data covering at least 60 years * with reliable data collections of temperature air mass and composition. Ocean salinity, density, volume and understanding of both pressure and current affects.at the surface and at all depths.Variations in atmospheric density, composition, fires, volcanoes, winds. Also volcanic effects, Tsunami effects, Anthropogenic CO2 and emission effects. Last the dynamics of planetary movement and of solar heat, magnetism and plasma effects.

We have some. We have an idea of what others we need to have. We have a starting point but we do not have an understanding of what the natural variations can be* and how often they can occur hence our risk assessment has a high inbuilt level of uncertainty.

People like looking for their lost keys under the streetlight because at least there they can see. Similarly Climate egnostics like to look at recent data and experience because that is what they know and are comfortable with. Secondly they like familiarity, normal is what one was born in and grew up with. But climate is much more unpredictable than what we have experienced in the last 20 to 70 years. My apologies to those too young, not enough data base and those too old, set in their ways.

Climate is the Grapes of Wrath years in America. In Australia we had our settlers in South Australia who grew wheat and sheep for 40 years successfully only for the true drought and heat conditions of that area of the world return to wipe them out. History is redolent with famines and feasts [the bible] The deserts of the ancient Egyptian food bowls. Little Ice Ages Roman warm periods..

The best and most simple, elegant example of complete misunderstanding of the risks has happened before our eyes with hardly a whimper from anyone involved. The Global Sea Ice extent. Here we have an example of dropping levels from the 1970’s satellite levels With a recovery due to the Antarctic ice going up to and over x2 SD for several years. In fact roughly 4 years ago we had for one month the highest sea ice extent on record for 1 month. Just 4 years ago.

Then we had a fall in both Arctic and Antarctic extent together in the last 3 years giving a 5-7 SD drop to the lowest figures recorded, now thankfully improving. I cannot emphasize this enough. A 7 SD difference is immense, mind boggling and in terms of risk either immensely significant or significant of something immensely wrong with our understanding of the real standard deviations normally available.The latter is the reality. We are able to have climate and weather fluctuations in terms of years that are a lot higher than what we currently cater for. This means that people who want to see risk can find it anywhere if they are prepared to lie to themselves. Highest temp in all of recording time [3 years] for the hill on the back of our block in Tennessee for one hour in July 13th? Shame about the bushfire. But also for people who desperately wish to see green shoots of recovery anywhere and choose the opposite cooling examples.

Things are not made any better by specious, sometimes  mendacious and precious commentary on the different measuring systems available when they disagree with one’s own precious views.Or by using anomaly measurements and making backwards adjustments to real temperature measurements.

Disclaimer, CO2 is real. CO2 by itself can make temperatures go up and it is a small but important balanced component of our atmosphere, hydrosphere and lithosphere.Some people like to argue an it is just atmosphere composition and gravity. Cart before the horse, no, just it is both cart and horse. If the CO2 goes up at a certain gravity and pressure then of course the temperature goes up as well. Both sides would do well to take a chill pill.

But CO2 is only one component of the complicated CO2 pathway for the atmosphere and due to the high carbonic content of the sea and the immense heat capacity of the oceans, which both give and take heat, Vegetation growth on land and sea, responses to CO2 addition are unclear and unknown

While chaos is an unknown, organisation is a given. The immense ocean buffering, the nature of our rocks and thin water envelope. The photosynthesis at this distance from the sun means that for human lifetime experiences, individually and collectively there is minimal risk of anything other than the gradual massive slow changes the earth has had for 2 of its 4 billion plus years.  This does not mean that on a decadal or centennial scale we could have changes that seem extreme to us, particularly when we panic.

Just do it

To learn Italian you have to speak it, rapidly, and know what the words mean or you will be left behind for dust.

The verb Fare or facere is one of the most important verbs and one of the best to start with. To do to act to make are some of the things you can say with it.

An interesting aside is that our English word far [as in far away] possibly comes from it. As in lontano fa a long way away. But I digress.

So lets do it. Let us do  it.  Facciomo lo.

We will start in a room in a house.

Cominceremo in una stanza in una casa. Another verb of many for starting is Inizieremo.

It is not important at the start to be totally correct in Italian. Fluency and choice will develop as you speak with or listen to people speaking the language. Here most English speaking people will be more comfortable with the verb Cominciare as it sounds like the word commence which is used more frequently that the word initiate for start in English.

Her we are using the ending for we or us, iamo, added to the verb, Cominciamo, iniziamo, partiamo etc. meaning we start. When we use the future tense we will start we instead add eremo to the base word.

In  can sometimes be the same as the English in. Or it can be nella or nello and variations on this according to the subject. Occasionally one uses fra or tra instead which are interchangeable. Tra in English is an additive part to a word meaning between or across as in transit Fra is used to give a range as in infra red. Both are used to indicate an in between property usually of time or space.

A is a term indicating singularity. Un is the base for masculine words often ending in o.
Una for feminine words usually ending in a.
Uno is of course used for the number one in Italian.

Stanza is the dictionary and accepted word for a room but there are many others.
The most commonly used being camera.We could also use commonly use sala.

Finally a house is a casa. Though there are other names for use in different circumstances.

Now for a bit of fun or as the Italians say  un po ‘di divertimento. Notice the un with the masculine word ending in o. It means Diverting as in entertaining by the way. Not diverting [taking away] attention but purely entertaining as in that was a diverting show, it took my mind off other things. Po means a little and di is one of the versions of the word of.

Try white house. Yes the president lives in one but so do a lot of other people.
Casa bianca. Bianca besides being a colour and a girl’s name is a version of blank. Which is like white paper that no one has written on. In Spanish it is blanco or blanca.

See rules in appendix

“A key point is that the system will always tend towards a state in which the amount of energy coming in, matches the amount going out into space, and that this state depends mostly on the boundary conditions.”
Would it be more appropriate to say this state determines the boundary conditions?
Energy in equals energy out is a scientific tautology.
The boundary conditions are implicit in the setup.
Time and size are important constraints given that humans live such very short lives compared to most of the time involved in climate change features. We live near a vanishingly thin water envelope on the earth [the oceans] where a vanishingly small alteration in sun energy output could spell curtains for us.
The hubris in expecting a perfect climate [defined I guess as what we had when [us old white men included] were born] is great. The fear of change is great and equates, I guess, with a fear of death.
Where I appreciate the discussion here is when people are more open to the challenges that present in using the data available openly and honestly even when it hurts.
[Garfield on the fence pose].
The fact that

Marco says: June 5, 2018 at 9:44 am
“Since when is motivational reasoning “a good thing”?
Take for example.
Going into something with the explicit starting point something is right means that you almost *have to* find something to be right.
It is called Confirmation bias for a reason, bias perhaps. Not always a skeptic problem.
Surely this is not a good thing?
On the other hand being scientific ie skeptical means having an open mind, not a bias to finding something negative. Could I adjust the sentence to start with an if to ease your concern and make the meaning clear, though “on the other hand” would seem to imply this anyway.
If ” On the other hand, if you find a mistake, or are able to question something they’ve done, then you potentially have ammunition if your goal is to undermine their results. This could be true, even if the consequences of this issue is negligible.”
Surely this is a good thing?

“In which case why mention the 97% unless it was just your usual trolling?”
So, in expert opinion there exists a 3% chance of being wrong.
No certainty then.
It is hard enough to put up arguments, sensibly, without anything that disagrees with your world view point being accused of being trolling. Why don’t you give me a break and try to work on convincing me with sensible arguments instead. I am trying to engage, admittedly it annoys you and I am sorry about that but discuss the arguments, not diss the person.
Thanks.
“angech wrote “I did not say it, JC, I found it. Argue your point with Best Schools, not me. And I acknowledged, did you miss it that JC was not a skeptic, yet.
How many times has she published articles on her blog questioning whether the rise in atmospheric CO2 is anthropogenic? How many times has she commented to agree that we know it is predominantly anthropogenic in origin? How many times has she rejected the mass balance argument, which shows that the natural carbon cycle is a net carbon sink and hence is opposing the rise and not causing it.”
JCH said June 6, 2018 at 3:08 pm
“Two of them clearly are not skeptics: JC and LB. Even Lindzen, if you read the transcript of the physics society roundtable, is a complete dud as a skeptic.”
So your view on JC as a skeptic is not shared by JCH, JC herself, WUWT [she was listed as a lukewarmer on the old site] or the skeptic community as a whole.
Like me, she has acknowledged the warming effect of CO2. Did you miss that? The fact that she has raised and raises questions is Skepticism, not denial.
A perfectly legal, temperate approach to science which you should embrace and answer.

I hate bullies. [right of pasage]

you hate bullies. we all hate bullies.

Nasty vile despicable bullies Giving us all trouble. Lousy smelly cvruel bullies.

Dontcha hate them loath  them despise them.?

Let’s sink the other boot in

What tight do they have to exist?

Let’s get rid of them forever. Gang up and crush them.

Is that a head? l

Lets kick it .

Stomp stomp stomp.

Nothing left except a bleeding mass of bully on the ground. Good . w

We have done it. Saved the village, saved the school Saved the world.

Congratulations/

. Iam ew are and most important of all.

You are now a bully.

How does it feel? Or in the words of that song. How does it feel?

Great actually. We won.

The health bully.

the politically correct bully dress codes.

So yes bullying is an effective useful  way of addressing problems. of learning how to cope in the world . A way of getting through life sucessfully. of leaarning how to cope with adversity.

Let us ask our bully shall we.

Are you still alive?

How did you feel after that experience/

Was it up lifting for you?

No sound, no response. Well you did put the boot in as many times as was necessary .

Some poeple do not make it through.

Ask yourself this question though. was it needed Yes Was it good yes

Are you a bully? No

Where have all the bullies gone, long time passsing whre have all the bullies gone a long time ago.

No one is a bully. We are all victims of bullies. Remember.

That is why we did the stomping.

No bullies here.

John Hartz says: May 4, 2018 at 6:44 pm
“Back to basics: Climate Sensitvity (CS) is an index created to compare model runs. It is model output, not a model input.”
Dave_Geologist says: April 27, 2018 at 2:43 pm
” Dessler’s point AFAICS is that if you take a suite of physics-based models, where you know the ECS in advance, and try to calculate it the way LC13 and LC18 do, you get the wrong answer.”
–
The old chestnut, Lucia [whom I trust] used it as well, is that ECS is an emergent property of climate models. The truth is that the ECS is hardwired into all the GCM.
At around 3C.
Put 3C ECS in and 3C ECS comes out.
Compare it to the real world, the only one, where 3C rarely comes out unless you pick exact time frames of extra warming like a decade ending in a large El Nino.
–
Consequence is shadow boxing, dodging the real questions and answers.
Dessler is right but so is Lewis but on two different stages.
It is so easy to answer a question on the first stage show in the second show arena.dikranmarsupial says: April 24, 2018
Even angech’s own sources refute him. His original claim was:
These can give an indirect record of past temperatures, but only locally. Such records indicate that Temperature changes equivalent to the modern 150 year warming have happened a number of times in the past 3000 years. [emphasis mine]
and he supports that with:
“The NRC committee stated that “The basic conclusion of Mann et al. (1998, 1999) was that the late 20th century warmth in the Northern Hemisphere was unprecedented during at least the last 1,000 years. This conclusion has subsequently been supported by an array of evidence that
includes both additional large-scale surface temperature reconstructions and pronounced changes in a variety of local proxy indicators”
and says: This basically agrees and supports what I have said. There are possible higher and lower spikes in the temperatures in the past that do not show because of “the wide error bars” as one goes backwards and the “uncertainties inherent in temperature reconstructions for individual years and decades are larger than those for longer time periods’.
–
DM “Err, no it doesn’t, it says that the recent warming is unprecedented.”
–
Having been called out in the past for not fully quoting comments I guess I can do a tu quoque?
The NRC did not say “the recent warming is unprecedented.” Mann et al said that.
The part that DM leaves out says clearly plausible only with substantial uncertainties before 1600.
I will append the bit he missed by accident.
–
“Based on the analyses presented in the original papers by Mann et al. and this newer supporting evidence, the committee finds it plausible that the Northern Hemisphere was warmer during the last few decades of the 20th century than during any comparable period over the preceding millennium”, though there were substantial uncertainties before about 1600?”.
–
“Note also the goal-post shift from “have happened” to such spikes being “possible”, without acknowledging the weakening of his position. Rather shabby.”
–
Sorry DM I have not changed my position. No goal post shift. Read my comment again noting “have happened” refers to events ” past temperatures, but only locally” which are well known and real.
The ”spikes” being possible refers to the separate concept that such temperature spikes may have been general rather than local and would not be visible due to the large error range in time and temperature.
Good try.

• BBD says:

  April 25, 2018 at 10:10 am

  I would like your opinions on the statistical probability of such events existing [my statement] rather than sidetrack to the question of how as you have an excellent understanding of the statistics involved.

  If no plausible physical mechanism exists that could produce a global warming of ~1C and ~150y in duration, there is nothing further to discuss.

  Since you cannot (will not) answer this question, I’d say we are done here.
• angech says:

  Your comment is awaiting moderation.

  April 25, 2018 at 10:51 am

  izen says: @-metzomagic
  “What physical process could possibly produce a 1 deg C spike in temperatures that disappeared without a trace within a 200 year time span?”
  It is a good question.
  A short global warming of similar magnitude to the present would need a large-scale cause.
  Solar variation.
  A large methane ‘burp’
  Albedo changes from massive global ice cover loss.”
  I could add
  Albedo changes from vegetation color changes,
  Algal or jellyfish sea plumes,
  widespread black soot deposits from a massive volcanic explosion/s,
  Prolonged excessive cloud formation,
  Two very large volcanic explosions 200 years apart.
  Recurrent runs of large El Nino events.
  or a combination of these events on smaller scales.
  A combination of several events might nudge the plausibility barrier.
  Two very large volcanic explosions 200 years apart would certainly do it but is not fair.
  I doubt that warming are only possible from massive global ice cover loss. All the ice one needs for evidence has melted.
  You have shown that some of the first scenarios lack the proof that would be needed for attribution. Most of the others should also have left some traces.
  “a lack of inevitable effects.
  We know what effects the current rapid warming has had. It is inevitable that any similar energy gain in the past would have the same effect. AFAIK there is no evidence that there was a similar sea level rise in the Holocene since the end of the de-glaciation.”
  Good point.
  –
  I suspect if there was it would show up in the timing and observable locations of solar and lunar eclipses.
  Too esoteric for me
  –
  “Otzi the ice man would have defrosted in any previous rapid warming as glacier mass balance shrinks. ”
  Depending on whether he fell in a crevice at the start or the end of the glacier, surely? And how long and big it was.
  –
  “While the proxies may theoretically be able to miss a short spike in the Holocene, there are other reasons to doubt it could happen and not be evident.”
  Perhaps this quote rebuffs your very good quote
  The absence of evidence is not evidence of absence.

   Look, I think the piling on is really healthy, happy to wear it and argue it to the hills, but only with the lighter weights.
  I want to avoid a Dikran vs angech comment thread, at all costs. I think Dikran’s point of view is explicit, and clear and totally different to mine.
  He is a lot more entitled to his views due to his senior status here and his scientific knowledge and expertise.
  That is not to say that I will not put up an alternative point of view and and discuss it with the rest of you if you address the same arguments.
  ATTP’s point
  “It’s almost 20 years since the publication of the first hockey stick paper (Mann, Bradley & Hughes 1998). The hockey stick refers to millenial temperature reconstructions that look a bit like a hockey stick; a period of centuries during which temperatures appear reasonably flat, or cool slightly (the shaft), followed by a period of rapid warming starting in the mid-1800s (the blade)”
  is something I concur with.
  I point out, mathematically why this must happen with any older proxy record.
  I point out that the standard deviations grow as we go back in time and are large enough to easily encompass 1C ranges of temperature for 150 years without it having to trouble the records.
  It cannot trouble the records because the SD is much larger than 1C.
  So why the fuss?
  Why do we have to say the past 3000 years ran along with nary a squeak off the railroad straight hockey shaft?
  Internal variation too large lets denialists claim a slight risk to the scientific consensus?
  Even though when we admit it is large enough short term we can show observational ECS is too low?
  Not my problem, nor yours either if you man up to the scientific facts and work with them.

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