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Nic Lewis's Climate Audit piece on Drew Shindell's TCR paper (BH discussion here) has engendered a response at Real Climate.
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That's a bit cryptic.
There are also a number of less substantive points in his piece that I will not bother with.
Shindell speaks with the typical patronising attitude of a climastrologist.
At the end of all the self congratulatory drivel, which is par for the course for "Surrealclimate", a sarcastic dig at Nic"For completeness, I should acknowledge that Lewis correctly identified a typo in the last row of the first column of Table S2, which has been corrected"
Then the usual alarmist send conclusion" Finally, I note that the conclusions of the paper send a sobering message. It would be nice if sensitivity was indeed quite low and society could get away with smaller emission cuts to stabilize climate. Unfortunately, several lines of independent evidence now agree that this is not the case."
Excuse me while I grab the sick-bag.
... the estimate of aerosol forcing used in the calculation of transient climate response (TCR) in the paper does not come directly from climate models, but instead incorporates an adjustment to those models so that the forcing better matches the assessed estimates from the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC).
We didn't use the models themselves but we tweaked them to reflect the IPCC's 'assessed estimates' (read 'guesses') that they included in AR5
well he did include a link to Climateaudit. Is this a first?
Hopefully RC will allow a response by Nic in comments
Apr 8, 2014 at 3:28 PM Mike Jackson
It's turtles models all the way down.
From Shindell post at RC:
The well-mixed greenhouse gas forcing in 1850 is 0.213 W/m². Including well-mixed solar and stratospheric water that becomes 0.215 W/m². LU and ozone almost exactly cancel one another. So to adjust from 1750-2000 to 1850-2000 forcings, one must remove 0.215 W/m² and also remove the -0.164 W/m² aerosol forcing, multiplying the latter by it’s impact relative to that of well-mixed greenhouse gases (~1.5) that gives about -0.25 W/m².
Anyone who thinks the well-mixed ghg forcing in 1850 IS 0.213 w/m^2, or that there is any reasonable basis to adjust global forcings from 1750-2000 to 1850-2000 when the forcings are largely unknown and highly uncertain is crazy.
The modellers behave as though the forcing curves specified by IPCC for CMIP through times back to 1850 or 1750 are "correct". Its complete nonsense.
They can argue about the minutae and "correctness" of the calculation but given the huge uncertainties on the input forcings its all arm waving and bullshit.
I would post at RC, but based on past experience no chance it will make it through moderation without censorship.
" Finally, I note that the conclusions of the paper send a sobering message. It would be nice if sensitivity was indeed quite low and society could get away with smaller emission cuts to stabilize climate. Unfortunately, several lines of independent evidence now agree that this is not the case."
Don - don't forget the primary purpose of RC is as a PR feed to the media. It is not an open scientific discussion site.
Sorry, I haven't been to SurrealClimate ever since, several years ago, Schmidt objected to one of my very relevant comments on peer review and deleted it. I shan't be returning there unless they allow a discussion.
Beyond the debate itself, which I leave to people more knowledgeable than I am in all matters atmospherical, the big novelty of this episode is that Real Climate publishes a response to a linked post at Climate Audit, thus recognizing at long last that CA exists as a channel for meaningful contributions to climate science. Moreover, the RC post by Shindell does it with utmost civility (even allowing for the occasional alarmist postscript, and some patronising tone which, however, this time is much less offensve or dismissive than it used to be in the past when skeptical blogs were only alluded ---never linked to).
Thus the outcasts are now recognised, to some extent, as legitimate participants in the conversation that orthodox climate scientists were having entirely among themselves with no regard for blogs, skeptics, dissenters, heretics and other evil spirits (dismissed as 'deniers' or 'oil industry shills') that were seen flying around their ivory tower. A positive development all in all, I should say.
"... several lines of independent evidence now agree that this is not the case."
People persist in calling model outputs "evidence" -- the uncertainties are often so huge that to claim there is model "evidence" seems beyond strained.
Fortunately (for Alarmists) there is Lewandowsky et al. here to claim that the greater the uncertainties the more urgent the demands for extreme action.
With such a perfect Rube Goldberg machine in play the Alarmists need never fear a falsifying result.
H.M., good point, the Michael Mann clique pretending that "he (they) must not be named or acknowledged" has suffered at least a temporary setback.
Martin A: re: Models all the way down.
iirc Betts came on here a year or so ago and explained that the MO had 17 models which they ran and the aggregated output was then pushed through a last model called: MAGICC.
Methinks the page views on Real Climate must have been sinking below the horizon. Somebody suggested that a way to increase traffic was to reference a CA post. Next up will be a review of Andrew's report on school curricula, followed by a much belated critique of Anthony's Stevenson Screen experiments.
The fact that there are now 14 comments here on the link and none at RealClimate on the actual post speaks volumes.
A pretty banal thing but I think what is most strange, thinking about how science and scientific method is supposed to work, is that with the pause in warming, the existance of which was denied for years and when aknowledged, pretty much everybody in the "climate science community" is trying to explain it away and nobody is asking an obvious question "hey, maybe there's something wrong with what we know?" A question that a good scientist should constantly ask. Even not a part of this knowledge, like TCR, can be questioned. And who does, is ridiculed and subjected to mob like attacks as a denier. That behavior is typical for activism, not science.
theduke: there are no comments at RC because the science is settled.
Bernie at 5:56: +1
In order to assist RC in their descent into irrelevance, I suggest that all discussion on Shindell's post be confined to Bishop Hill. The chances of a critical post being published over there are slim anyway. Although I suppose Nic Lewis will want to respond and that they will graciously allow him that exalted privilege.
But yes, it's a good sign they are responding to a post on CA and I commend Gavin for that. Now all that remains is for him to allow an open, free-wheeling discussion like you find on CA.
Do people read Real Climate blogposts? Why?
Wouldn't you be better reading stuff from real scientists!
Just yesterday I was thinking how long it had been since anyone mentioned what was going on in Real Climate. It is as if it completely dropped out of everyone's radar screen. Now they pop up again, this time humbled enough to link to the 'anti-science' Climate Audit.
I'd like to add my voice to those above and suggest that no one, including Nic Lewis, go to that doomsday cult territory to comment, lest the cult think they're credible again.
I don't go to "Real Climate". I always felt as if I'd just visited the seediest part of town when I went there.. It's the last refuge of people like "Mad Dhog Dhogaza".
I often wonder if any of the climastrologists who wander the globe by passenger jet would consider boarding any of these aircraft if the models used in aircraft design were only subjected to the level of validation and verification to which their own climate models have been subjected?
The comments there will appear, once they've passed the censor to remove criticism and such "Denierist" stuff!
I maintain there is only one criticism required: He assumes models are adequate for the task despite all evidence to the contrary. After that blooper it doesn't matter what he waffles.
"For completeness, I should acknowledge that Lewis correctly identified a typo in the last row of the first column of Table S2, which has been corrected"
Finally, I note that the conclusions of the paper send a sobering message. It would be nice if sensitivity was indeed quite low and society could get away with smaller emission cuts to stabilize climate. Unfortunately, several lines of independent evidence
ALL OUR WORK IS PEER REVIEWED ! ASSHOLES !!
My favorite RealClimate utterance (from http://www.realclimate.org/index.php/archives/2004/12/co2-in-ice-cores/):
At least three careful ice core studies have shown that CO2 starts to rise about 800 years (600-1000 years) after Antarctic temperature during glacial terminations. These terminations are pronounced warming periods that mark the ends of the ice ages that happen every 100,000 years or so.Does this prove that CO2 doesn’t cause global warming? The answer is no.The reason has to do with the fact that the warmings take about 5000 years to be complete. The lag is only 800 years. All that the lag shows is that CO2 did not cause the first 800 years of warming, out of the 5000 year trend.
Does this prove that CO2 doesn’t cause global warming? The answer is no.
The reason has to do with the fact that the warmings take about 5000 years to be complete. The lag is only 800 years. All that the lag shows is that CO2 did not cause the first 800 years of warming, out of the 5000 year trend.
Mickey Reno points out something important: for the AGW consensus to hold up, they must rely on an explanation that is basically, "....and then something wonderful happened" to hold their ideas together.
My first exposure to climate nastiness was my question on Groaner's CiF about the existence of standards in measuring daily temps in response to an obvious bit of nuttery from their leading climastrologist; suddenly all kinds of foaming-at-the-mouth activists shot out of the metaphorical woodwork, jumping all over me for daring to ask a question and didn't I know the science was settled and how dare I embarrass myself by asking rude questions.I began searching WUWT about then and discovered the answers I had been looking for, but I was thankful to the self-styled 'attack dogs' and other assorted crazy people who were regulars on CiF for introducing me to Bishop Hill and similar organs for cicilised discourse.I occasionally scroll through the responses on CiF to remind myself just how nastily tribal the AGW movement is.
"For completeness, I should acknowledge that Lewis correctly identified a typo in the last row of the first column of Table S2, which has been corrected".
But I note that neither Shindell's corrected SI nor the NASA GISS notice linking to it acknowledge me for pointing out the (admittedly small) error.
I'm not planning to respond at RealClimate in view, mainly, of their censorship policy. But I have posted a comment on a highly relevant thread at Troy Master's blog, here. Troy's post was made several weeks ago, but I only learnt of it today through a comment he posted at RealClimate. Troy's post pretty well demolishes Shindell's findings, showing that his TCR estimation method fails badly on the models used to derive it. Well worth reading.
Shindell's post at RealClimate doesn't address most of my substantive criticisms of his paper. Moreover, it states in relation to TCR estimation:
"One could assume that there was minimal global mean surface temperature change between 1750 and 1850, as some datasets suggest, and compare the 1850-2000 temperature change with the full 1750-2000 forcing estimate, as in my paper and Otto et al."
That is plain wrong in relation to Otto et al (2013), which actually compared 1850-2000 temperature changes with 1850-2000 forcing changes (actually means over 1860-79 with means over the 2000s and other recent periods). Its Supplementary Information makes this very clear. I find it a little worrying that one of my coauthors on Otto et al doesn't seem to properly understand the paper, or even to have read its Supplementary Information.
Mike Jackson quoted Drew Shindell:
and then observed
No mention here of something as inconvenient as 'observations'!
But Shindell's very next sentence was
An adjustment is necessary because as climate models are continually evaluated against observations evidence has become emerged that the strength of their aerosol-cloud interactions are too strong (i.e. the models’ ‘aerosol indirect effect’ is larger than inferred from observations)
So I'm confused as to where the discussion of observations is absent. It looks like Shindell is claiming that the estimate of aerosol forcing has been brought in line with observations, at least to some extent, rather than just relying on the model outputs. This may not have been done correctly, but it certainly looks like observations are mentioned in this context. In fact it looks like Shindell's defense against Lewis' criticism is precisely that his numbers are justified by observations rather than just models.
Is it some other estimate where the discussion of observations is missing?
While I'm not familiar with the study, or their methodology. I get the impression they used a model to estimate the amount of earisol forcing, and then validated their model against current climate models, to come to the conclusion that "Therefore studies based on observed warming have underestimated climate sensitivity as they did not account for the greater response to aerosol forcing..."
"Lewis then argues that the large uncertainty ranges in E and in aerosol forcing make it the TCR estimates “worthless”. While “worthless” is a little strong,..."
So, Shindell considers those results as almost worthless, then?
And with my post here, that makes it three times as many posts at BH than at RC. Hi guys at RC, I think your efforts at "climate science communication" are heading towards an empty echo chamber. Perhaps you might now admit your historical moderation policy aimed at playing to your sycophants was a mistake?
JKI stand corrected.But the point is still that the adjustments are made in order to bring the forcing in line with AR5's assessed estimates.It would have been better (even if it stuck in his teeth) to say that the estimate of aerosol forcing comes from observations — which is where it should come from. Whichever way it is still largely guesswork.
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