Tuesday, April 12, 2016

A Simple Sea Level Rise Model

... because curve-fitting is so much fun.

Background

Mark Bofill raises an interesting question over at Lucia's:
SLR is evidence warming is occurring. It doesn’t put the A in AGW though, FWIW. It’s always seemed to me that sea level rise started a trifle early for CO2 increase to be the original cause.
There being a number of SLR reconstructions floating about, I asked which one(s) he's been looking at.  He proposed I we have a look at Jevrejeva et al. (2008), Recent global sea level acceleration started over 200 years ago?
Abstract: We present a reconstruction of global sea level (GSL) since 1700 calculated from tide gauge records and analyse the evolution of global sea level acceleration during the past 300 years.  We provide observational evidence that sea level acceleration up to the present has been about 0.01 mm/yr 2 and appears to have started at the end of the 18th century.  Sea level rose by 6 cm during the 19th century and 19 cm in the 20th century.  Superimposed on the long-term acceleration are quasi-periodic fluctuations with a period of about 60 years.  If the conditions that established the acceleration continue, then sea level will rise 34 cm over the 21st century.  Long time constants in oceanic heat content and increased ice sheet melting imply that the latest Intergovernmental Panel on Climate Change (IPCC) estimates of sea level are probably too low.


A Quick Discussion of the Paper

I typically look at the pretty pictures first, here is the first one most relevant to this discussion:


There are other versions out there without the polynomial fit, which is what I'm used to seeing.  And indeed, the link Mark provided for me didn't have the trend line either.  Here's what I had to say as an initial response:
… the trend looks to start going up around 1780, is wiggly until about 1850, and basically linear from that point on. That about right?
That worked for him.  Here's one more figure from the paper itself:

I like this better than a simple polynomial fit.  The 30 year trend windows does bring out the 60 year quasi-periodic rate fluctuation mentioned in the abstract.  And finally, the upward-sloping rate plot indicates an accelerating trend.

A 60-year cycle smells like AMO to me.  I may not be too far off; from the paper:
A global pattern of 60-year variability is supported by comparison of the GSL and North East Atlantic variability (Figure 3), where a similar pattern of variability is seen, though with differences in amplitude and timing of prior to 1950, which are suggestive of an Atlantic driving mechanism. This may be related to an underlying variability in the thermohaline circulation [Delworth and Mann, 2000], perhaps through advection of density anomalies or combinations of gyre and overturning advection [Dijkstra and Ghil, 2005]. However, direct observational evidence on these long cycles in thermohaline circulation is very limited and modelling using coupled Global Circulation Models (GCMs) show rather ill-defined power on these timescales [Knight et al., 2005].
Mann (2009) presents an AMO reconstruction going back to 500 CE.  Had it already been published it would have been interesting to see what Jevrejeva & Co. might have done with it, if anything.  My first instinct was to not use Mann's reconstruction because it's not de-trended, and we're more interested in CO2's putative influence on SLR than what might be manifest in Atlantic SSTs.  That didn't mean I wished to ignore other plausible mechanisms which might have contributed to the "early" SLR and/or some of the wiggles.

A Dirt-simple Multiple Regression Model

Total solar irradiance (TSI) is one obvious candidate.  The paper mentions volcanic activity -- I myself was already thinking Tambora in 1815, and Krakatau in 1883.  But I only have volcanic aerosol data back to 1850 my fingertips.

There is one not so obvious candidate; length of day anomaly (LOD), data for which I have all the way back to 1623 CE.

CO2 data are of course easy to find going back hundreds of thousands of years.

So, without further ado, here's the quite elementary multiple linear regression model of SLR I managed to kluge together:

Figure 1 - SLR regression model.  120-month trailing means for all data series except TSI (132-months).  CO2 and TSI are lagged 360 months.

The fit is actually fairly good for CO2 only, but the TSI and LOD combine to slight rise starting around 1790, the flat trend from 1820-1880, and the seemingly early upward trend beginning around the turn of the 20th century.

I have some other interesting tidbits to add from work done by peer-reviewed professionals, which I plan to add to this note as updates.  For now, I'm going to rush this to press so Mark and others can have a looksee.

Update 4/15/2016

In comments, Mark Bofill refers us to a slide presentation by Dr. Trenberth.  The text of slide 12 reads:
Where does energy go?
• An imbalance at TOA of 1 W m-2 is 3.2x10 7 J/yr m-2 = 1.6x10 22 J/yr globally
• To melt 10 6 km 2 ice 1 m thick (2007) to 10 C = 0.8x10 20 J
• To produce 1 mm rise in sea level requires melting 360 Gt ice or 1.2x10 20 J Plus 12.5% to warm melted waters to ambient 1.35x10 20 J
• To produce 1 mm rise in sea level by warming the ocean (thermosteric) depends greatly on where energy is placed
• Fresh water has a maximum in density at 4 C, but not so for sea water.
• Coefficient of expansion varies with temperature and pressure by factor of 6 from 0 C to 20 C
• For warming over top 700 m to give 1 mm can take from 50 to 75x10 20 J, or below 700 m 110x10 20 J
• Hence melting ice vs warming ocean is a factor of about 40 to 70 more effective in raising sea level (if in top 700m) or 90 (if below 700 m)
1 W m-2 gives sea level rise of 93 mm (melting ice) vs 3 to 1.5 mm (thermal expansion)
• Need to distinguish eustatic vs thermosteric sea level rise wrt energy
From these figures, Mark argues:
1. It's much cheaper energy-wise to get SLR from melting ice than thermal expansion of sea water.
2. Even so, Dr. T gets only 93 mm for each W/m^2 forcing increase,
3. Which means about 372 mm for a doubling of CO2 I think? 4 W/m^2?

So the problem is that the model, although it fits bee-a-utifuly, doesn't appear to be physically correct. There's not enough energy for that much SLR for that much CO2 increase.
Which is a nice way of saying my simple linear regression model above is busted.  If it's not immediately apparent why, note carefully the title of my Figure 1 above, which puts CO2's contribution to SLR at 1.23 meters for a doubling of CO2.  The canonical radiative forcing calculation for CO2 doubling is:
5.35 W/m^2 * ln(2) = 3.71 W/m^2
Multiplying by 93 mm m^2/W gives 344 mm of SLR per CO2 doubling.  This implies that my regression model is magnifying CO2's effect on SLR by a factor of 3.6.

Not so fast.  CO2 is the dominant anthropogenic forcing since at least 1950, but it is not the only one (note that there are some negative ones as well).

And then there are feedbacks.  The Met Office provides an enumeration with short descriptions, though no numbers.

The dominant positive feedback is water vapor.  Trying to track it down in AR5 is a pain, but to my knowledge the AR4 estimate is still valid (plus it's in handy HTML format instead of the abhorrently bulky slow-loading .pdf documents of AR5):
In the stratosphere, there are potentially important radiative impacts due to anthropogenic sources of water vapour, such as from methane oxidation (see Section 2.3.7). In the troposphere, the radiative forcing due to direct anthropogenic sources of water vapour (mainly from irrigation) is negligible (see Section 2.5.6). Rather, it is the response of tropospheric water vapour to warming itself – the water vapour feedback – that matters for climate change. In GCMs, water vapour provides the largest positive radiative feedback (see Section 8.6.2.3): alone, it roughly doubles the warming in response to forcing (such as from greenhouse gas increases). There are also possible stratospheric water vapour feedback effects due to tropical tropopause temperature changes and/or changes in deep convection (see Sections 3.4.2 and 8.6.3.1.1).
See Footnote [1] for why this confuses me.  Ignoring my confusion; taking the above paragraph as written, water vapor amplifies 3.71 W/m^2 forcing per CO2 doubling by a factor of 2 to 7.42 W/m^2, implying 688 mm of SLR in that scenario.

There are of course other feedbacks.  Rather than try to look them all up and net them out as a function CO2 change, I will "cheat" by simply grabbing some LW flux variables from the CMIP5 RCP6.0 model ensemble.  Since Dr. Trenberth is talking about radiative imbalance at TOA, one's first instinct might be to grab outbound LW flux at TOA from the models.  It does not make sense to do so for my simple linear regression model approach:

Figure 2 - Modelled outbound LW at TOA from CMIP5 historical/RCP6.0 ensemble.  Source: KNMI Climate Explorer.
For this exercise, I thought it made more sense to go after either the up or down LW flux variable, here's what downwelling LW flux at the surface looks like:

Figure 3 - Modelled inbound LW at surface from CMIP5 historical/RCP6.0 ensemble.  Source: KNMI Climate Explorer.
That makes more sense.  Regressing that against the RCP6.0 CO2 scenario over the entire 1861-2100 interval gives 17.44 W/m^2/2xCO2.  Divide by 3.71, and we get a factor of 4.7 over the expected forcing of a CO2 doubling alone.  This seems promising.  However ...

Don't quote that figure.  Reason being, it's inclusive of other GHG increases, changes to aerosols and land use, as well as all as the net of all feedbacks.  I only use it here to allow CO2, being the dominant driver of AGW, as kind of a proxy for roughly guesstimating what SLR might look like under the RCP6.0 CO2 emissions scenario:

Figure 4 - Projected SLR using RCP6.0 Surface Downwelling LW only.  All series trailing 120 month means, no lags.




This model gives 45 mm SLR for every 1 W/m^2, Trenberth is calculating 93.  So by all rights, I should be projecting on the order of 1.4 m of SLR by 2100.  As well, over the first part of the 21st Century, I'm projecting GMSL well higher than present observational estimates, on the order of 20 cm.  Why?

As BBD points out in comments below:
Hot off the presses at Nature Climate Change we have Slangen et al. (2016) Anthropogenic forcing dominates global mean sea-level rise since 1970.
 Going to the paper, we read:
Under CMIP5 control run forcing, most contributions show little variability, and no significant trend on a centennial timescale (Fig. 1a). However, if the glacier model is initiated to its 1850 state and then forced with control run variability, there is a contribution of 30 ± 13 mm for 1900–2005 (cyan) as a result of the continued retreat of glaciers to higher altitudes after the Little Ice Age (LIA relaxation) 5,11, as glaciers typically take decades to centuries to establish a new equilibrium after climate changes.
In my first model, Figure 1 above, I used a 30-year lag for CO2 and solar forcing.  If in the Figure 4 model, we mentally slide the projected curve forward 30 years, the 2100 projection works out to about 50 cm of SLR over the 1986-2005 baseline mean for RCP6.0.  Let's see what the IPCC actually projected:

Figure 5 - GMSL projections for all RCPs.  After AR5 SPM Figure 9, credit: Aslak Grinsted.

For RCP6.0, the central estimate for the 2081-2100 mean is ... 50 cm, about where my model would put it if I laid in a 30-year lag in forcing.

Damn I'm good.  Or maybe just lucky.

This doesn't really answer Mark Bofill's original question, at least not directly.  At the very least I better understand the arguments for the IPCC SLR projections being conservative ... here I make it by about half.  Exploring that would be interesting, and I will perhaps dig into that in a future article.

Footnotes

[1] If we first consider Table 3 from Kiehl and Trenberth (1997), water vapor accounts for about 75 W/m^2 and CO2 about 32 W/m^2 of the "greenhouse effect" in clear sky conditions, 51 and 24 W/m^2 respectively under cloudy conditions.  That gives a water:CO2 ratio of about 2.2:1.

For sake of argument, it seems reasonable to assume a linear relationship for a CO2 doubling: 1 + 2.2 = 3.2.  We are looking to explain an apparent discrepancy in my simple model of a factor of 3.6, so invoking water vapor feedback gets us pretty close, with other net feedbacks making up the difference.  Yet AR4 tells us to only expect an amplification factor of 2.

So I'm confused.  Perhaps some literati out there can help a buddy out here.

81 comments:

  1. Very nice Brandon. I will take a close look.
    BTW, what the heck is Length Of Day anomaly? Never heard of it. I'm sure google will tell me, but.
    Thanks!

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    1. LOD anomaly comes from changes to the rate of Earth's rotation. Over the very long term it is slowing down, which on millenial scales is purported to have some effect on sea levels. It also fluctuates on decadal time scales. I know of at least two science/engineer types whom I don't consider bonkers supposing that it can have an effect on surface temperature due to how the acceleration/deceleration affects ocean currents. I've regressed it against GISTemp and HadCRUT4 myself, and there seems to be something to it. I can dredge up links if you'd like to know more.

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  2. Alright Brandon. Here's my problem.
    I take http://www.cgd.ucar.edu/cas/ace/presentations/trenberth1.pdf slide 12 as my reference. I actually ~did~ compute the energy required to melt 360 Gt of ice myself, but I threw my hands in the air when it came time to try to figure out the energy needed for thermal expansion of seawater. Googling the question brought me to Dr. Trenberth, thank God.
    So slide 12 appears to give us what we need:
    1. It's much cheaper energy-wise to get SLR from melting ice than thermal expansion of sea water.
    2. Even so, Dr. T gets only 93 mm for each W/m^2 forcing increase,
    3. Which means about 372 mm for a doubling of CO2 I think? 4 W/m^2?

    So the problem is that the model, although it fits bee-a-utifuly, doesn't appear to be physically correct. There's not enough energy for that much SLR for that much CO2 increase.

    Whatcha think.

    BTW Thanks for all of your work on this, it's very interesting!

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    1. Mark,

      Bee-a-utifully argued. I've been doing some checking on my own, and 1.2m SLR per CO2 doubling, when plugged into RCP6.0 does gives ~1 m SLR by 2100 ... which I think is well high by a factor of 3 or so.

      Other problem is, it predicts SLR from 2002 on well high of the observed rate (both tide gauges and radio altimetry from satellites).

      So this model is probably busted.

      I've done one other thing, fit SLR to HADCRUT4. It gets some of the wiggles correct, but not all the trends. And of course it only goes back to 1850, not 1700. I was thinking about trying Berkeley Earth next.

      I will also try using Mann's AMO reconstruction.

      I'm glad you are enjoying this exercise, thank you for giving me an idea for an article ... it's not always easy to figure out things to write about.

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    2. Hey don't worry about it either. When do we ever get anything worth doing right the first try? I can make a computer say 'hello world' on the first try, anything more complicated than that usually takes multiple iterations and successive approximation.
      FWIW, since I accept radiative physics, it's basically unavoidable to conclude that at least some of SLR is anthropogenic. It's interesting to try to puzzle out how much.
      Oh, a last thought. The 3.7 or 4 W/m^2 is supposed to just be the straight increase in radiative forcing. Maybe you can come up with some of the extra energy you need by supposing positive feedbacks.
      Not good for my position for a lukewarmer if so! But still, it's a thought.

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    3. Mark,

      I did intend to make this article an ongoing discussion of discover. But I should have checked that model for out of sample SLR against more current datasets before letting it go, and given the 2100 projection a smell test as well.

      So very nice to have a contrarian voice who is being properly skeptical about this. I agree, it's interesting to try to figure out for ourselves the "how much". In the end, I'll likely just end up posting the latest and greatest estimates from literature, which are based on far more complicated maths than I'm capable of reproducing, but I do have fun and good learning experiences attempting to go it on my own.

      I already have calcs posted elsewhere for OHC increase in energy per unit area. It may be possible for me to do some modelling from 1950-present, and hindcast the results in an attempt to essplain the trends in the late 19th Century. We shall see.

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  3. Gosh, I just noticed the lags. 30 years? Mebbe I guess, I don't know about that.

    Anyway, thanks again and some more. :)

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    1. I figure some lag is to be expected. But yes, these are the potential hazards of curve fitting. The real place to go for answers is in literature from the pros, and I've got some papers already in the queue to explore. I often find it helpful to knoodle this stuff on my own first, it can help me better understand what I'm reading.

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  4. Also Brandon, we might be jumping to conclusions. There seem to be experts who think 1.5m by 2100 is a reasonable upper bound. Maybe positive feedbacks make the difference:
    http://www.glaciology.net/Home/Miscellaneous-Debris/ar5sealevelriseuncertaintycommunicationfailure
    I'm calling it a night and expect to have a relatively busy day tomorrow, but I'll continue to play with this as time permits.
    Thanks!

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  5. Hot off the presses at Nature Climate Change we have Slangen et al. (2016) Anthropogenic forcing dominates global mean sea-level rise since 1970.

    The abstract reads (emphasis added):

    Sea-level change is an important consequence of anthropogenic climate change, as higher sea levels increase the frequency of sea-level extremes and the impact of coastal flooding and erosion on the coastal environment, infrastructure and coastal communities1, 2. Although individual attribution studies have been done for ocean thermal expansion3, 4 and glacier mass loss5, two of the largest contributors to twentieth-century sea-level rise, this has not been done for the other contributors or total global mean sea-level change (GMSLC). Here, we evaluate the influence of greenhouse gases (GHGs), anthropogenic aerosols, natural radiative forcings and internal climate variability on sea-level contributions of ocean thermal expansion, glaciers, ice-sheet surface mass balance and total GMSLC. For each contribution, dedicated models are forced with results from the Coupled Model Intercomparison Project Phase 5 (CMIP5) climate model archive6. The sum of all included contributions explains 74 ± 22% (±2σ) of the observed GMSLC over the period 1900–2005. The natural radiative forcing makes essentially zero contribution over the twentieth century (2 ± 15% over the period 1900–2005), but combined with the response to past climatic variations explains 67 ± 23% of the observed rise before 1950 and only 9 ± 18% after 1970 (38 ± 12% over the period 1900–2005). In contrast, the anthropogenic forcing (primarily a balance between a positive sea-level contribution from GHGs and a partially offsetting component from anthropogenic aerosols) explains only 15 ± 55% of the observations before 1950, but increases to become the dominant contribution to sea-level rise after 1970 (69 ± 31%), reaching 72 ± 39% in 2000 (37 ± 38% over the period 1900–2005).

    So natural (lagged) ocean warming post-LIA dominates until ~1950 and the anthropogenic signal becomes strongly dominant thereafter (post 1970). This would be why explaining early warming using anthro dinnae work. To nobody's great surprise, I imagine, given the relative weakness of anthropogenic (CO2) forcing pre-1950 and the further back you go.

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  6. Slangen et al. is very interesting. What it shows is - I think - that the C20th trend in SLR arises from an ever-increasing anthropogencic component (GHGs + aerosols). Early C20th anthropogenic forcing accounts for only about 15% of SLR. By the late C20th (1970) this has risen to ~70% and has continued to rise to the present.

    Terrestrial ice sheets and glaciers exhibited a lagged response to the increased temps post-LIA (post-1870 in S16). This lagged melt was the principal driver of early SLR, slowly diminishing and giving way to ever-increasing anthropogenic forcing during the C20th.

    Here's pretty picture that summarises the data.

    Full paper (read only) is available here.

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    1. Good stuff, BBD, thanks. I really must make a point to finish this post tomorrow; will read your cites with interest and try to digest them into some sanity ...

      ... urgh, just took a peak at Slangen, pretty dense, but the concluding paragraph is relatively plain English:

      Our comprehensive set of simulations demonstrates three main results. First, although natural variations in radiative forcing affect decadal trends, they have little effect over the twentieth century as a whole. Second, in 1900, sea level was not in equilibrium with the twentiet h-century climate, and there is a continuing, but diminishing, contribution to s ea-level change from this historic variability. Third, the anthropogenic contribution increases during the twentieth century, and becomes the dominant contribution by the end of the century. Our twentieth-century number of 37 ± 38% confirms the anthropogenic lower limit of 45% found in ref. 8. Our results clearly show that the anthropogenic influence is not just present in some of the individual contributors to sea-level change, but actually dominates total sea-level change after 1970.

      I'm not immediately finding how long the lagged ice response is ... oh wait, here:

      Under CMIP5 control run forcing, most contributions show little variability, and no significant trend on a centennial timescale (Fig. 1a). However, if the glacier model is initiated to its 1850 state and then forced with control run variability, there is a contribution of 30 ± 13 mm for 1900–2005 (cyan) as a result of the continued retreat of glaciers to higher altitudes after the Little Ice Age (LIA relaxation) 5,11, as glaciers typically take decades to centuries to establish a new equilibrium after climate changes.

      Which makes total sense. The next question is ... what caused the initial rebound from the LIA. I don't think it's a simple as TSI bouncing off the Maunder Minimum.

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    2. Which makes total sense. The next question is ... what caused the initial rebound from the LIA. I don't think it's a simple as TSI bouncing off the Maunder Minimum.

      First, I think the term 'rebound' should not be used. It plays to 'sceptic' misrepresentations of the way the climate system works ('recovery' from the LIA etc.) Climate isn't a bouncing ball. It only responds when *pushed*.

      But that aside, I agree that trying to make it all about TSI is misguided. The LIA was almost certainly multifactorial not the result of a singular forcing change. Several different mechanisms have been proposed (Maunder minimum; volcanism; NAO; NH high-latitude ice albedo feedback) so there's no imperative to ascribe the end of the LIA to a singular forcing change.

      The key point here, at least as I see it, is that Mark's question is answered - without casting any doubt on the scientific understanding of AGW.

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    3. [sigh] more seepage. I've delivered your speech about "rebound" more times than I can count. I repent.

      With Slangen, and some of the other papers I should be able to cobble together a suitable conclusion to this article tomorrow.

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    4. We all do it ;-) I would just like to discourage Mark from following the left hand path on this one.

      No rush for the conclusion. I just wanted to get the references to this brand new paper up asap as very relevant to the discussion.

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    5. BBD,


      ...First, I think the term 'rebound' should not be used. It plays to 'sceptic' misrepresentations...
      ...is that Mark's question is answered - without casting any doubt on the scientific understanding of AGW...
      ...We all do it ;-) I would just like to discourage Mark...



      So, this bums me out. I get the impression that I'm going to screw this up, that I'm going to say something and give unintentional offense (because I'm not sure I understand where this is coming from) or blunder in some similar way through lack of understanding or failure of clear communications. It's always a danger, I guess all I can do is give it my best shot. I say this in advance so that it's clear that being offensive isn't my intent. Ideally I'd like to be able to hang out and talk here with you BBD, you and Brandon and anybody else who comes by, that's my main immediate goal, and being offensive doesn't serve that purpose. Besides which it goes against the grain anyway.

      But here it is: I don't understand why you are speaking so carefully and why you are encouraging Brandon (and me I guess) to speak so carefully. I'd guess it has something to do with consensus messaging in some way, or ... I don't know exactly. If you want to explain this to me I'd be quite interested in listening. Until I understand why we ought to do this though, let me say it seems like a helluva lot of trouble to take. I don't normally review my words carefully to figure out how they might cast doubt on something, or how they might play to misrepresentations -- that's alot of trouble. I mostly just blurt out whatever crosses my mind. :) Often that leads to me blurting out stupid and wrong things - seriously, it does. Couldn't we just talk informally without all the concern? Nobody with any sense takes me seriously anyway.

      Just trying to understand and get along here, again, I'm not looking to pick a fight.

      Thanks.

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    6. Mark

      But here it is: I don't understand why you are speaking so carefully and why you are encouraging Brandon (and me I guess) to speak so carefully. I'd guess it has something to do with consensus messaging in some way, or ... I don't know exactly. If you want to explain this to me I'd be quite interested in listening. Until I understand why we ought to do this though, let me say it seems like a helluva lot of trouble to take.

      Because there is a misinformation machine. So, it is necessary to be precise. In this case, a classic paper would be Akasofu (2013). This proposes an obviously unphysical mechanism for modern warming and prompted a reply (discussion here) and the resignation of the editor responsible for its publication.

      It has *nothing* to do with 'consensus messaging'.

      * * *

      Minor stuff aside, I hope you found Slangen et al. interesting and useful in the light of your original question.

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    7. BBD, I haven't looked at it yet. But I certainly will, thanks!

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    8. This comment has been removed by the author.

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    9. No rest for the wicked. I still haven't looked at this, and I've got to get up and go take care of other stuff shortly. I promise, it's still in my queue BBD!
      Really quickly, I've been meaning to ask. In layman's terms, why is SLR from melting ice such a laggy process? I get the sense that it is but I've got no clue about why. Anyone willing able to explain this in simple terms?

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    10. Terrestrial ice sheets form in cold places (obvs, I know) which preserves them for a time against hemispheric / global warming. They also create their own (cold) local climate through high albedo and often high surface altitude (eg. Greenland ice sheet). Finally, ice sheets have substantial inherent thermal intertia and tend to melt slowly - at least initially.

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  7. Finally read the paper! Thanks for pointing it out BBD, I thought it was extremely interesting. Also, thank you for the simple explanation about ice sheets. Like most things, makes sense once I hear the explanation, but I'd have never realized it without the explanation. :)
    I'll be chewing on the paper for a little while. If I can find any time I might go look at the methods and see if I can follow what they did at all.
    Again, thanks so much.

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    1. Glad it was useful. It certainly helped me think more clearly about the question you raised.

      I hope you don't mind me asking, but would you mind summarising your general position? I think you referred to yourself as a lukewarmer, but that's a bit vague and I'd like to understand where you are coming from properly. Always a prerequisite for sensible conversation :-)

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    2. I certainly will. My wife is looking at me tapping her foot waiting (she protests that she's not and that I'm a liar, but.. ) so I've got to run again, but I will be back later. Sorry.

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    3. So yes, I'm a lukewarmer. By this I mean, I don't dispute the basic radiative physics of AGW. I don't dispute that we are pumping bukuloads of CO2 into the atmosphere and increasing the amount of CO2 in the atmosphere. We're going to see some warming from it. How much? The IPCC recognizes a range and I think they are wise to do so. Climate sensitivity still isn't known for sure. The uncertainties lie in the feedbacks as I'm sure you know as well (if not better) than I do.
      I understand that some people are strongly persuaded by the paleo record. I consider the paleo record to be evidence, but I personally am not satisfied that it is conclusive with respect to CS. Also, some find the models strongly persuasive. I don't utterly disrespect the models the way many contrarians do, but still; these are very complicated models modeling phenomena that are not all perfectly understood - and we know perfectly well we are not modeling at the spatial resolution we'd like because it's not computationally convenient. We know we've got parameters for some stuff we can't model well. Bottom line I think the models are extremely cool and are maybe the best tools we have, but. The problem of understanding our climate in sufficient detail for good modeling and implementing good models of it is not a trivial one.

      More generally:

      I'm not a physical scientist of any sort, bachelor degree level from a state school in computer science 25 years ago. Conservative, sort of.

      I am more interested in understanding the debate than in participating in it, truthfully. I'm interested in the policy end of the issues as well, and I'm curious about the ... PR type issues. For example, the 97% consensus meme is (as I understand it) thought to be important for consensus messaging, which is thought to be one of the things that might shift public opinion and support towards a certain set of policies. I am keenly interested in seeing how this plays out, either way.

      I always enjoy hearing other people's take on the climate debate.

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    4. BBD, I expect this is clear, but FWIW I thought about it. I understand that you don't appreciate remarks that seem to be made out of a motive to cast doubt on solid science, to help delay action. I wasn't trying to do that, I was trying to explain where I'm coming from. To some extent explaining what I see as our differences inevitably was going to involve expressing sentiments I know you disagree with, but I hope you realize my motive was just to answer you and not to climb up on a pulpit to spread a point of view.
      I hope this makes sense.

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    5. Mark,

      As usual I appreciate your thoughtful comments, and here especially a description of your present position. It all looks to be appropriately skeptical of the present state of climate science as you understand it, for which you have my respect.

      I have but one question of you: given the many various uncertainties expressed by the IPCC and literature at large, but knowing human activities are having some effect, do you not think the most appropriate action is to proceed with caution?

      Pending your answer, we might then have an interesting and fruitful discussion about appropriate actions given your personal perceptions of risk, and policy decisions you might or might not find acceptable.

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    6. Mark

      Thank you for your response. One immediate question arises:

      I understand that some people are strongly persuaded by the paleo record. I consider the paleo record to be evidence, but I personally am not satisfied that it is conclusive with respect to CS.

      Why not? To hold such a position, you need a coherent scientific argument. What is yours? It needs to counter this:

      Making sense of palaeoclimate sensitivity, (2012), Nature, 491, 683–691, doi:10.1038/nature11574 (PALAEOSENS Project Members*)

      Many palaeoclimate studies have quantified pre-anthropogenic climate change to calculate climate sensitivity (equilibrium temperature change in response to radiative forcing change), but a lack of consistent methodologies produces a wide range of estimates and hinders comparability of results. Here we present a stricter approach, to improve intercomparison of palaeoclimate sensitivity estimates in a manner compatible with equilibrium projections for future climate change. Over the past 65 million years, this reveals a climate sensitivity (in K W−1 m2) of 0.3–1.9 or 0.6–1.3 at 95% or 68% probability, respectively. The latter implies a warming of 2.2–4.8 K per doubling of atmospheric CO2, which agrees with IPCC estimates.

      Everything known about palaeoclimate behaviour points to a sensitivity range in good agreement with the models. The central ECS estimate is about 3C per doubling; other studies indicate that ESS is somewhat higher - ~5C.

      The fundamental problem with lukewarmerism is that it requires that the palaeoclimate evidence is - effectively - denied without any formal justification whatsoever. It's inconvenient, so it just gets shoved off the table. And that is not good enough.


      * PALAEOSENS Project Members: Rohling, E.J., Sluijs, A., Dijkstra, H.A., Köhler, P., van de Wal, R.S.W., von der Heydt, A.S., Beerling, D., Berger, A., Bijl, P.K., Crucifix, M., deConto, R., Drijfhout, S.S., Fedorov, A., Foster, G., Ganopolski, A., Hansen, J., Hönisch, B., Hooghiemstra, H., Huber, M., Huybers, P., Knutti, R., Lea, D.W., Lourens, L.J., Lunt, D., Masson-Demotte, V., Medina-Elizalde, M., Otto-Bliesner, B., Pagani, M., Pälike, H., Renssen, H., Royer, D.L., Siddall, M.,Valdes, P., Zachos, J.C., and Zeebe, R.E.

      Delete
    7. I'm interested in the policy end of the issues as well, and I'm curious about the ... PR type issues. For example, the 97% consensus meme is (as I understand it) thought to be important for consensus messaging, which is thought to be one of the things that might shift public opinion and support towards a certain set of policies.

      You don't know your climate history :-)

      The origins of consensus messaging go back a long way, at least to 1998. That was the year when a bunch of fossil fuel industry shills sat down and thrashed out a strategy for derailing the public understanding of climate science. Fortunately for posterity (and keen historians of organised denial such as ourselves), they set out their strategy in a memo, which has survived.

      C13 and other consensus studies are attempts to rebut the meme created by the denial machine that there is a *lack* of consensus among climate scientists. C13 is an attempt to redress the balance in favour of the truth: there is a near-unanimous scientific consensus that climate change is real, caused by us and potentially dangerous.

      Here's an excerpt from the API memo, with the more egregious falsehoods in bold:

      The advocates of global warming have been successful on the basis of skillfully misrepresenting the science and the extent of agreement on the science, while industry and its partners ceded the science and fought on the economic issues. Yet if we can show that science does not support the Kyoto treaty - which most true climate scientists believe to be the case - this puts the United States in a stronger moral position and frees its negotiators from the need to make concessions as a defense against perceived selfish economic concerns.

      Upon this tableau, the Global Climate Science Communications Team (GCSCT) developed an action plan to inform the American public that science does not support the precipitous actions Kyoto would dictate, thereby providing a climate for the right policy decisions to be made. The team considered results from a new public opinion survey in developing the plan.

      Charlton Research's survey of 1,100 "informed Americans" suggests that while Americans currently perceive climate change to be a great threat, public opinion is open enough to change on climate science. When informed that "some scientists believe there is not enough evidence to suggest that [what is called global climate change] is a long-term change due to human behavior and activities," 58 percent of those surveyed said they were more likely to oppose the Kyoto treaty. Moreover, half the respondents harbored doubts about climate science.


      Vested interest and its stooges (witting and unwitting) have now been peddling these lies for over a quarter of a century. The truth is as set out in C13: the scientific consensus is nearly universal. C13 isn't a "... PR type issue" and it isn't a 'meme'. It's a response to a systematic and long running attempt by vested interest to deceive the public.

      Delete
    8. BBD,

      I appreciate the link and will examine this within the next few days. Until I have time to look at this in detail, all I can think to ask in response is, how is it the IPCC reports state that climate sensitivity is uncertain and lies in a range between a low and high value if the scientific evidence is conclusive that climate sensitivity is high? This does not appear to make sense to me, why I am required to admit to confidence in a narrower range of CS than the IPCC does.
      But I will read your link, perhaps there is evidence I will find persuasive that I have overlooked or misunderstood.

      Thanks.

      Delete
    9. I can't speak for BBD, but I wouldn't argue that evidence for CS ~3 is conclusive. Strongly suggestive at best, as determined by convergence on that value from multiple lines of evidence and observationally-constrained modelling.

      Delete
    10. PS, Knutti and Hegerl (2008) is my go-to reference for this. AR5 cites it, and uses Figure 3 in the report. Keep in mind that for any given future emission scenario, ECS only buys us (or takes away) time. How much depends on the rate of GHG increase and the "do not exceed" temperature threshold.

      Delete
    11. This does not appear to make sense to me, why I am required to admit to confidence in a narrower range of CS than the IPCC does.

      AR5 made a mess out of the sensitivity chapter because they couldn't integrate the lowball estimates being produced by the newly-fashionable EBM approach. AR4 was more coherent:

      Since the TAR, the levels of scientific understanding and confidence in quantitative estimates of equilibrium climate sensitivity have increased substantially. Basing our assessment on a combination of several independent lines of evidence, as summarised in Box 10.2 Figures 1 and 2, including observed climate change and the strength of known feedbacks simulated in GCMs, we conclude that the global mean equilibrium warming for doubling CO2, or ‘equilibrium climate sensitivity’, is likely to lie in the range 2°C to 4.5°C, with a most likely value of about 3°C. Equilibrium climate sensitivity is very likely larger than 1.5°C.

      I will make a rare bet. Now the problems with EBM estimates are clearly understood, AR6 will state that ~3C remains the central best estimate.

      One final but important point typically not acknowledged by lukewarmers is that the values within the range are not all equally likely. Very low sensitivity is *unlikely* as is very high sensitivity. Choosing a very low value without formal justification is an act of faith, not reason.

      * * *
      how is it the IPCC reports state that climate sensitivity is uncertain and lies in a range between a low and high value if the scientific evidence is conclusive that climate sensitivity is high?

      That's perilously close to a strawman. Let me repeat exactly what I wrote above:

      Everything known about palaeoclimate behaviour points to a sensitivity range in good agreement with the models. The central ECS estimate is about 3C per doubling.

      Not the absence of the word 'conclusive'. The problem with lukewarmerism is that there is *no* evidence that sensitivity is low enough to make mitigation unnecessary. Everything known points the other way: sensitivity is high enough for unabated emissions to be potentially extremely dangerous.

      Delete
    12. Brandon

      PS, Knutti and Hegerl (2008) is my go-to reference for this. AR5 cites it, and uses Figure 3 in the report.

      K&H08 is a key reference. It is very clear on the distinction between likely, very likely and most likely. It took me a while to realise that a large number of contrarians treat all values within the sensitivity range as equally likely. K&H08's Fig 3 alone provides an instant corrective to that mistake.

      Delete
    13. It took me a while to realise that a large number of contrarians treat all values within the sensitivity range as equally likely.

      Except that they automatically assume that low sensitivities are more likely than the high end of the range. That's one thing I always say to them: If you accept the low end probability, you then have to equally accept the high end range near 4.5°C.

      I can't think of any real response anyone's ever given to that. Usually the subject changes at that point.

      Delete
    14. RobH

      Except that they automatically assume that low sensitivities are more likely than the high end of the range.

      Yes. Of course that's what I meant to say :-) Everything's terribly uncertain *except* low CS.

      Delete
    15. This comment has been removed by the author.

      Delete
    16. So, I'm not trying to annoy you guys. Any honest answer I supply is not going to delight you. Please remember that you have asked me my views on this, I have not come here to preach uncertainty or cast doubt on anything. In fact, it's contrary to my purposes for being here to discuss it. This said, I was asked courteously so in good faith I will answer:
      I am not a scientist. I observe the following:

      1) Since IPCC’s first report in 1990, assessed projections have suggested global average temperature increases between about 0.15°C and 0.3°C per decade for 1990 to 2005. This can now be compared with observed values of about 0.2°C per decade, strengthening confidence in near-term projections. {1.2, 3.2}
      • Model experiments show that even if all radiative forcing agents were held constant at year 2000 levels, a further warming trend would occur in the next two decades at a rate of about 0.1°C per decade, due mainly to the slow response of the oceans. About twice as much warming (0.2°C per decade) would be expected if emissions are within the range of the SRES scenarios. Best-estimate projections from models indicate that decadal average warming over each inhabited continent by 2030 is insensitive to the choice among SRES scenarios and is very likely to be at least twice as large as the corresponding model-estimated natural variability during the 20th century. {

      This didn't appear to happen this way.

      2) Models appear to be running hot.

      And conclude that perhaps the best guestimate we've got is high.

      I've got other reasons that are too tedious for me to be willing to explain casually. These are the easiest.



      Delete
    17. Natural variability overprints the forced signal on decadal timescales so you cannot use a short interval to make any inference about TCR let alone ECS.

      Basic conceptual error.

      Delete
    18. 2) Models appear to be running hot.

      - Actually moot. Not even sure if I agree at this point with the AR5 suggestion that the CMIP5 ensemble is 10% hot

      - Even if correct, the effect is far too small to make a difference to the public policy implications

      Delete
    19. Oh, and:

      the best guestimate

      Please do not indulge in word-placement games.

      Delete
    20. Right, well I thought it was clear from my response that I didn't expect that you would find my explanation persuasive. Obviously you disagree, this is fine by me. I hope this satisfies whatever motive or curiosity prompted the original question.
      Thanks.

      Delete
    21. It's not that they're not persuasive, Mark. They're pretty much wrong.

      Sorry.

      Delete
    22. BBD,

      Please do not indulge in word-placement games.
      I am discussing a topic you are interested in and that you have asked me about, not one that I am interested in. I answered you out of courtesy. I have repeatedly attempted to make clear that I have no interest in 'spreading doubt' about the science. I have no intention whatsoever of spending any more time than I already do (because I actually DO this for 5 or 10 minutes every time I comment here) reviewing and sanitizing my responses for your benefit. If you do not wish to accept that I am speaking in good faith, that is your privilege. 'Guestimate' is a word I use a lot as a computer programmer, because in our field estimates are notoriously difficult to get right. It's use in my response had no meaning. I would appreciate it if you would read my responses with some modicum of charity and effort to understand, if you intend to continue to talk with me.

      Delete
    23. Nothing to be sorry about RobH, that's fine.

      Delete
    24. Mark

      A painstakingly evolved scientific estimate is not a 'guesstimate' and the use of that term is inappropriate. Please don't persist in defending the indefensible.

      On which topic - lukewarmerism. I have been endeavouring to show you that there is no evidence supporting this position. Lukewarmerism is the product of misconceptions, misrepresentations, wholesale evidence denial and acts of faith, not a balanced overview of the scientific evidence.

      So, why do you adhere to a position that isn't scientifically defensible in favour of one that is? *That's* what interests me.

      Delete
    25. Well, that's nice that that interests you. It doesn't particularly interest me, not enough anyway that I'm going to spend any more time than I already do choosing my words carefully in order to talk with you.

      Delete
    26. I used to be a lukewarmer, Mark. Until I forced myself to stop the denial and work objectively through the evidence. It was unpleasant and distressing but nevertheless, I have never once looked back.

      Delete
    27. Mark -

      Re: your 6:22 (April 16)...although there are points of divergence between you and myself (some fairly important), I think that what you wrote there is entirely reasonable.

      One important distinction is that I think that although the 97% issue attracts a lot of attention in the climate-o-sphere, it is mostly peripheral to where the real policy rubber meets the public opinion road.

      FWIW.


      Delete
    28. Mark Bofill,

      So, I'm not trying to annoy you guys. Any honest answer I supply is not going to delight you.

      Looks like I'm late to my own party.

      I'll tell you my main frustration here -- as I do, please keep in mind I've been banging on at Lucia's *all day* with this. Saying the models look hot is meaningless unless you, or anyone, make an argument for what that means with respect to policy. Leaving it dangle implies *to me* that you, or anyone, is saying there's no need for urgency and/or there's simply not a problem. That may not be fair to you, but it is one of my personal prejudices simply by virtue of having been around this debate long enough. As I hope you realize by now, I'm also willing hear out arguments if I think they're being given in good faith -- which in your case I do.

      So. I'm not shy about talking about CMIP5 being 10% hot over the historical runs. All that means to me is that we *might* have a little more time before hitting whatever arbitrary threshold one picks as the do-not-cross line. It doesn't solve the problem, nor does it mean it isn't there. That's my position, and why it frustrates me when folk say teh modulz are hot ... [dot dot dot]

      Do with that as you will. Cheers.

      Delete
    29. BBD,

      Actually moot.

      Agree, but ...

      Not even sure if I agree at this point with the AR5 suggestion that the CMIP5 ensemble is 10% hot

      It's my reading of box 9.2 in AR5 WGI (p. 31 of the .pdf):

      ------------------

      Model Response Error

      The discrepancy between simulated and observed GMST trends during 1998–2012 could be explained in part by a tendency for some CMIP5 models to simulate stronger warming in response to increases in greenhouse gas (GHG) concentration than is consistent with observations (Section 10.3.1.1.3, Figure 10.4). Averaged over the ensembles of models assessed in Section 10.3.1.1.3, the best estimate GHG and other anthropogenic (OA) scaling factors are less than one (though not significantly so, Figure 10.4), indicating that the model-mean GHG and OA responses should be scaled down to best match observations. This finding provides evidence that some CMIP5 models show a larger response to GHGs and other anthropogenic factors (dominated by the effects of aerosols) than the real world (medium confidence). As a consequence, it is argued in Chapter 11 that near-term model projections of GMST increase should be scaled down by about 10% (Section 11.3.6.3). This downward scaling is, however, not sufficient to explain the model-mean overestimate of GMST trend over the hiatus period.


      ------------------

      I've regressed the ensemble over 1861-2005 against HadCRUT4, and get about the same result. I have not read the fuller discussion mentioned in chapter 11.

      Even if correct, the effect is far too small to make a difference to the public policy implications

      There we agree fully. My *guesstimate* is that it makes < 15 years difference for hitting +1.0 above the 1986-2005 mean for RCP8.5 if we're to believe HadCRUT4. Maaaybe a decade if GISTemp is closest to reality.

      Delete
    30. PS, obviously RCP6.0 or lower would lengthen the buffer, one of these days I'll figure that out as well.

      Delete
    31. Brandon

      If the feedback response to temperature increase is non-linear - which is my current understanding - then the 10% hot issue is going to be an irrelevance anyway. I think this may be why the AR5 text reads:

      near-term model projections of GMST increase should be scaled down by about 10%

      * * *

      PS, obviously RCP6.0 or lower would lengthen the buffer, one of these days I'll figure that out as well.

      Have you come across this RCP visualisation tool? It's rather good.

      Delete
    32. Joshua

      One important distinction is that I think that although the 97% issue attracts a lot of attention in the climate-o-sphere, it is mostly peripheral to where the real policy rubber meets the public opinion road.

      Yes, I see that you have been saying this a lot, recently. But why so sure? I thought the surveys showed that public confidence in the science increased when the public was made aware of the strength of the scientific consensus. This presumably broadens the support for mitigation policy - the electorate will be more supportive of mitigation policy the more it accepts the science. Why is this wrong?

      Delete
    33. BBD,

      I'm tired, it being well past bedtime, and snippy having chased six too many squirrels at Lucia's today so this may sound more cross than it ought.

      I saw "near term" *this time* I read the damn thing, and the imprecision is hacking me off. Normally that would mean a decade, but in this context it doesn't make sense to me because that's on the verge of being weather noise, and they explicitly say it doesn't explain the divergence over the GMST "hiatus period". So "near term" to me here means 30-ish years. And over that amount of time, 10% hot would only buy us an additional 15 years at best. Which is nothing.

      So ... we agree.

      I had not seen the RCP visualization tool, will check it out tomorrow, thanks for the tip. Stay safe out there. Cheers.

      Delete
    34. PS, I'll weigh in on consensus messaging. I think Joshua is questioning the correlation between public perception and politician "perception". It all comes down to whether the pols pander more to public opinion, or to returning campaign finance favours.

      I'm going with the latter. But this is an all options on the table scenario, so I've got zero problem with consensus messaging.

      Delete
    35. BBD -

      ==> But why so sure?

      I'm not sure. Maybe I indicated "pseudo-precision" that I didn't intend? :-)

      ==> I thought the surveys showed that public confidence in the science increased when the public was made aware of the strength of the scientific consensus.

      I haven't studied the literature in-depth, but from what I've seen so far, the evidence is pretty weak (showing a relatively small effect) and (more importantly) relies on investigations done in non-reality based experimental conditions. In the real world, "consensus-messaging" comes from sources that are already aligned within a politicized constellation. In other words, someone like Obama saying that 97% of scientists agree isn't likely to have much significant impact in the real world. "Skeptics" will chafe, and some "realists" will feel supported, but most people will just go "meh." IMO, the drivers and mechanisms behind who the public aligns on climate change are quite complex, and not likely significantly influenced by such a surface-level endeavor.

      I don't reject the idea that "consensus-messaging" has worked by pointing to the current state of public opinion (the argument being that so many "skeptics" about proves that it doesn't work). I think that there's no way to really know whether "consensus-messaging" has significantly mitigated "anti-consensus messaging." I suspect, however, I'd only be convinced one way or the other by longitudinal type studies in real world contexts. My sense is that the claims of the "gateway effect" are influenced by wishful thinking. The "band-wagon" effect is real, and certainly we all use an assessment of "expert" opinion to make decisions all the time - but the context of climate change is set apart, IMO, by virtue of the intense level of politicization...and thus analogizing from other contexts seems not terribly useful, IMO.

      Delete
    36. Joshua

      There's a frighteningly large percentage of the US public that believes that there's no strong scientific consensus on AGW (is it 50%? something of that order, I think). What's not clear is that these same people are 'sceptics' already because politically and/or religiously conservative. They might be, in which case you are more likely to be correct. But if they are simply *misinformed*, then they represent a substantial persuadable base. Anyway, I'm reasonably sure we understand each other's position at this point so I'll leave it at that.

      Delete
    37. Joshua, BBD,

      This is part of what I find so interesting about the 97% consensus work. At this point, I'm not really interested in whether or not there were methodology errors or protocol problems or whatever. I'm not even particularly interested in the truth of the exact number; I think it's obvious that there's a large consensus. What I am fascinated by is watching this play out. Will it work? Will this be an effective tool for increasing the public's confidence in the science? Will it have an impact on support for policy? This is the interesting experiment in my view; not the paper, but whether or not the paper will be effective.
      I share some of Joshua's misgivings, but I honestly don't have an expectation one way or the other. I'm not sure how it's going to play out.

      Delete
    38. Mark -

      Actually, as it turns out you and I are on pretty much the same page here afterall. I feel like I could have written your comment...well...except that while sometimes I'm tempted to say that it's fascinating, at other times I'm more inclined to consider it remarkably banal (can something be remarkably banal?) It's mostly just sameosameo that will NEVER be resolved...largely due the overriding component of "identity protective cognition." It is mostly, IMO, Identity aggression and identity defense for its own sake. The bickering is the point. Sameosameo, with an added dash of personality politics: Tol vs. Cook, Dana vs. Brandon. Etc., etc.

      BTW, as an aside, your bud Lucia once told me that I don't actually think that the bickering over the quantification of the "consensus" is irrelevant even though I told her I did think it is irrelevant (expressing very much the same perspective as you did in your comment). When someone tells me they know my opinion better than I know my opinion, I suppose that it inclines me to think that they aren't engaging in good faith in future intereactions.

      Delete
    39. Mark -

      Actually, as it turns out you and I are on pretty much the same page here afterall. I feel like I could have written your comment...well...except that while sometimes I'm tempted to say that it's fascinating, at other times I'm more inclined to consider it remarkably banal (can something be remarkably banal?) It's mostly just sameosameo that will NEVER be resolved...largely due the overriding component of "identity protective cognition." It is mostly, IMO, Identity aggression and identity defense for its own sake. The bickering is the point. Sameosameo, with an added dash of personality politics: Tol vs. Cook, Dana vs. Brandon. Etc., etc.

      BTW, as an aside, your bud Lucia once told me that I don't actually think that the bickering over the quantification of the "consensus" is irrelevant even though I told her I did think it is irrelevant (expressing very much the same perspective as you did in your comment). When someone tells me they know my opinion better than I know my opinion, I suppose that it inclines me to think that they aren't engaging in good faith in future intereactions.

      Delete
    40. Joshua,

      Thanks! Another development I'm watching with some interest is the Exxon campaign. I actually do have an opinion there. I think it's going to work out the DA's. There's a precedent, and these guys will know how to make a case, and at least some of them are going to win. What effect it will have in the end, how much of an effect, that's a question, but unless something I haven't thought about develops, it's looking like green lights to me on Exxon hunting season.

      Regarding Lucia, for some reason you came up recently in an exchange between me and Lucia, and I mentioned (and I really do believe this) that I don't think you and she were communicating very well. Don't think either of you understood what the other was trying to say. But whatever right. It's pointless to rehash such things here and now, at least in my view.

      Delete
    41. Mark

      I'm wondering when are you going to address the scientific indefensibility of lukewarmerism.

      BG thinks you are here in good faith. I am not so sure at all since you have dodged every single point I raised on this thread which isn't how I define good faith.

      Delete
    42. Mark -

      I'm kind of the same mind about the Exxon thing as I am of the consensus thing as I am of the ROI thing and the Lamar Smith thing and the email of "skeptics" thing and the RICO thing and the Mann vs. Stern thing. Mostly alarmists SELECTIVELY hyperventilating about the "chilling effect" of this outrage or that tyranny or those infringements of free speech...which will, in the end, not change much of anything in the the real world. Yes, the tobacco investigation had real impact, mostly economic cost to massively rich corporations along with the betterment of regulation of a harmful substance (e.g., outlawing advertisement targeting children - of course, they just moved on to target people in other countries)...but hardly anyone (anyone at all?) went to jail and I think anyone would be hard pressed to show how there was some "chilling effect" on the private sector. Fraud is still a major economic force in our country.

      Mostly, I see it as political theater (I hope that doesn't sound like a Trump supporter). Not to disparage people's intentions, which I have no particular reason to think aren't completely justifiable....but I think that mostly it's about us vs. them. I tend to doubt that there will be evidence with Exxon that will be as clear cut as with the tobacco industry, anyway.

      Agreed about rehashing. Yeah, could well be just talking past each other. Probably the most plausible explanation. I think most people in these discussions hear what's in their heads more than what the other person has say. I certainly know that happens a lot when I try to talk to "skeptics" (present company excluded) so it would be irrational for me to think it doesn't flow the other way. There are fundamental techniques for good faith exchange which are routinely, almost uniformly, ignires if not outrught violated in almost all blogosphere electron swapping.

      Delete
    43. BBD,

      Look, I'm sorry if you thought I was here to argue my views on AGW. I'm not. We've all done that a million times, what for, is the way I see that. My idea is to try to understand as much as I can (and help people understand things about me) around the issues we disagree on.
      .
      We could talk about AGW. I think we've all done that enough to understand the general branches the discussion can take and the ways it usually ends. I don't see the point in repeating the exercise.
      .
      Given that, I'm trying to push the boundaries I know how to push. Why not make a real effort to talk with the guys on the other side about what we can talk about. Try to understand them as much as possible. The original idea I had was a little different, this has evolved a bit over time.
      .
      We could argue our views. Our disagreements would escalate to the point where one or the other of us would walk away. Typically it gets emotional, or offensive, or misunderstandings occur. I think Joshua is on to something with his thinking about identity defense, and the climate change arguments are sometimes just rationalized proxies for different forces. Maybe spending time getting to know and respect the people we disagree with can mitigate this.
      .
      Or not. Maybe it's as big a waste of time as anything else I do on the internet, that's a lot more likely than not. :) But what the heck? It's fun.
      .
      Maybe at some point we'll play ClimateBall if you still want to. I don't want to get on that roller coaster yet and have to exit the discussion here two and a half minutes later when the vehicle comes to the inevitable full and complete stop after the fun's over.

      Delete
    44. Joshua,

      I hope that doesn't sound like a Trump supporter

      I'm going to be chuckling the rest of the afternoon. Joshua the Trump supporter.. talk about 'through the looking glass'! LOL.

      Delete
    45. Just posted this at Judith's.


      I have to admit, while i started out skeptical of Trump, I’ve come around. I think what pushed me over the top was when i realized how deeply he was moved by 7/11.

      How can you not vote for a guy who takes convenience stores that seriously?


      http://nypost.com/2016/04/19/donald-trump-confuses-911-with-7-eleven/

      Delete
    46. Mark: My idea is to try to understand as much as I can (and help people understand things about me) around the issues we disagree on.


      BBD: So, why do you adhere to a position that isn't scientifically defensible in favour of one that is? *That's* what interests me.


      Mark: Well, that's nice that that interests you. It doesn't particularly interest me, not enough anyway that I'm going to spend any more time than I already do choosing my words carefully in order to talk with you.


      Sigh.

      Delete
    47. Joshua,

      What effect it will have in the end, how much of an effect, that's a question, but unless something I haven't thought about develops, it's looking like green lights to me on Exxon hunting season.

      Something I have been glancing at with interest as well. I have been wondering how damages would be assessed, and wondering whether putting a too-savage burn on the largest publicly traded fossil fuel provider is in everyone's best interest.

      And what would the blowback look like?

      That's another article I'm "supposed" to have written since, what, at least a week now.

      Delete
    48. Brandon -

      Did you confuse Mark's comment with mine?

      Delete
    49. This comment has been removed by the author.

      Delete
    50. Mark -

      Don't know if you quit ATTP....I left some "thoughts" for you over there.

      Delete
    51. Joshua,

      I saw, thanks. :)
      .
      I'm not sure if I quit or not. It's slippery. Past a certain point it's counterproductive to be there, if it turns into an issue/struggle with the regulars. I guess I'll wait and see. No worries though.
      .
      I begin to grasp why people comment at Climate Etc. It's the closest thing to a neutral zone there is, despite the fact that Judy's on a side.
      .
      Always interesting anyways thanks Joshua.

      Delete
    52. Re: Judith:

      I suppose it might be the closest thing to a neutral zone... hard to say... it is certainly a zoo...but it's also hard for me to be unbiased...as I get a special treatment...

      For example, I tried to post the following link earlier tonight, and she refused to pass it through moderation - despite that she routinely allows far worse attacks against me, over and over, from particular individuals.

      http://lmgtfy.com/?q=site%3Ajudithcurry.com+%22ristvan%22%2B%22warmunist%22

      Rud hardly ever writes a comment without including something about rmunists," yet he writes comments like this:


      https://judithcurry.com/2016/04/21/the-denialism-frame/#comment-779783

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    53. Joshua,

      Did you confuse Mark's comment with mine?

      Indeed I did. Whoops.

      Hi Mark!

      Delete
    54. ... er, actually I did realize it was Mark's comment, but wrote Joshua. Requesting a new brain please. Stat.

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  8. Brandon, I see that I ignored your question above. My apologies.

    do you not think the most appropriate action is to proceed with caution?

    Pending your answer, we might then have an interesting and fruitful discussion about appropriate actions given your personal perceptions of risk, and policy decisions you might or might not find acceptable.


    Certainly I think caution is warranted. The real question is how far to go. Some steps seem easier than others. I believe you are a proponent of nuclear power / fission power plants. Me too. I understand that they are expensive, but we could discuss the options here. My impression (and it is just an impression) is that some of the expense is somewhat artificial and could be tamed.
    Still, there is little question that natural gas will continue to be cheaper than nuclear for some time to come. How to best encourage the switch to nuclear? A carbon tax? A carbon credit trading scheme? EPA mandates? These questions are harder. The details start becoming important. The cost of the cure shouldn't be more expensive than the disease untreated, and the damages of the disease untreated depend on CS.
    Not much of an answer I guess. Long day. I think I work harder on the darn weekends than I do during the week. It's sad.

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    1. Mark,

      No sweat, I'd already gathered that your RL was busy this weekend ... plus I've been quite content to read your other comments here and about.

      It being that time to post a new article, I'm going to elevate this discussion. Look for it sometime tomorrow. Goodnight and good luck.

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  9. Brandon G,

    Would you prefer to talk over here? You get a lot of static on the BlackBoard, and there isn't anything I can do about that. Except that I can volunteer to talk over here I guess. :)

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    1. I'm perfectly capable of talking anywhere.

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  10. After Transjordan, the Arab country most involved in the first Arab-Israeli war was Egypt. Unfortunately for the Arab effort, Retro Jordans,Egyptian troops were often poorly led and badly supplied, reducing the effectiveness of their contribution. A variety of other Arab states also participated but tended to limit their involvement in actual combat. The Iraqis, who had generated some of the toughest rhetoric on the war, did little in the way of fighting, with their primary contribution being the occupation of defensive positions on the West Bank. Baghdad was also exceptionally unsupportive of King Abdullah in this instance, despite being ruled by a friendly Hashemite dynasty. While Iraq had a strong grudge against Palestinian leader Haj Amin Husseini for supporting a 1941 coup attempt to oust the Iraqi monarchy, Jordans for sale,Iraqi leaders also recognized that their own population was deeply pro-Palestinian and recoiled at suspected Transjordanian plans to annex any portion of the country that was kept out of Jewish hands.10 Military coordination between Iraq and Transjordan suffered as a result of this situation.

    On the northern front, Syrian forces participated in fighting south of the Sea of Galilee, but tended to avoided major conflict during the latter part of the war. There were a variety of reasons for this approach, one of the most important of which was the miserable relations between Amman and Damascus. authentic jordans, The Syrian leadership feared that an Arab victory in Palestine would lead to the expansion of Transjordan authority into whatever Palestinian territory was kept out of Israeli hands, dramatically increasing the power of their rival in Amman. In a similar manner, Lebanon assembled a small expeditionary force which gained some territory at the beginning of the war but was then rapidly pushed back into defensive positions by the Israelis.

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