Thursday, December 15, 2016

Atmospheric water vapour is a feedback (not forcing) - on Watts and Eschenbach #AGU16 poster

Sou | 11:08 AM Go to the first of 34 comments. Add a comment
Willis Eschenbach has a poster at AGU16, to which Anthony Watts added his name. Anthony's now written a blog article about it (archived here). Actually, Anthony put his name first although I strongly suspect he doesn't have a clue what the poster is all about.

They haven't made the poster available on the AGU16 website, or not at the time of this article. It is downloadable on Anthony's blog at WUWT, here.  He's also made available what he calls "data and code". The file is 500 MB or so, therefore I won't be downloading it till I get home in 20 hours or so.

There are a few points I'll make:
  • The poster is based on a couple of blog articles by Willis Eschenbach at WUWT, including the one I wrote about here.
  • Willis Eschenbach still doesn't know the difference between a forcing and a feedback (more below). Nor does Anthony Watts.
  • Their poster supports what real scientists tell us, that there's more water vapour in the air because of global warming.
  • Most of the data they use is ocean only, not land.
  • They seem happy to rely on RSS data, while disparaging it elsewhere.
  • They seem happy with lots of data carefully collected and analysed by climate scientists, despite calling it fraudulent elsewhere, and despite WUWT-ers wanting to stop all research.

To demonstrate that Willis and Anthony don't know the difference between forcing and feedback, at the bottom of the third panel of the poster, Willis wrote:
There is a clear trend in the TPW data. The total change over the period is ~ 1.5 kg/m2, centered around the long-term mean of 28.7 kg/m2. Utilizing the relationship between water content and atmospheric absorption derived above, this indicates an increase in downwelling radiation of 3.3 W/m2 over the period. Note that this 3.3 W/m2 increased forcing from the long-term increase in water vapor since 1988 is in addition to the IPCC-claimed 2.3 W/m2 increase since 1750 in all other forcings (see Figure SPM-5, IPCC AR5 SPM5). The IPCC counts as forcings the long-term changes in the following: CO2, CH4, Halocar-bons, N2O, CO, NMVOC, NOx, mineral dust, SO2, NH3, organic carbon, black carbon, land use, and changes in solar irradiance, but not the long-term changes in water vapor.

Key finding
This leads us to a curious position where we have had a larger change in forcing from water vapor since 1988 than from all the other IPCC-listed forcings since 1750.
Thing is of course that the statements in the IPCC report are about forcing. The increase in water vapour is a feedback, or response, to that forcing. This is what is stated in the IPCC AR5 SPM report, above the reference to Figure SPM.5, to which Willis and Anthony referred. I've emphasised the parts Willis and Anthony either didn't read or failed to understand:
Natural and anthropogenic substances and processes that alter the Earth's energy budget are drivers of climate change. Radiative forcing14 (RF) quantifies the change in energy fluxes caused by changes in these drivers for 2011 relative to 1750, unless otherwise indicated. Positive RF leads to surface warming, negative RF leads to surface cooling. RF is estimated based on in-situ and remote observations, properties of greenhouse gases and aerosols, and calculations using numerical models representing observed processes. Some emitted compounds affect the atmospheric concentration of other substances. The RF can be reported based on the concentration changes of each substance15. Alternatively, the emission-based RF of a compound can be reported, which provides a more direct link to human activities. It includes contributions from all substances affected by that emission. The total anthropogenic RF of the two approaches are identical when considering all drivers. 
In other words, forcing up (higher temperature) causes a feedback of more atmospheric water vapour, and the combined effect is included in the chart below. Correction: The chart below isn't the combined effect of forcing and feedback, it's just the radiative forcing.

Figure 1 | Radiative forcing estimates in 2011 relative to 1750 and aggregated uncertainties for the main drivers of climate change. Values are global average radiative forcing (RF15) partitioned according to the emitted compounds or processes that result in a combination of drivers. The best estimates of the net radiative forcing are shown as black diamonds with corresponding uncertainty intervals; the numerical values are provided on the right of the figure, together with the confidence level in the net forcing (VH – very high, H – high, M – medium, L – low, VL – very low). Albedo forcing due to black carbon on snow and ice is included in the black carbon aerosol bar. Small forcings due to contrails (0.05 W m–2, including contrail induced cirrus), and HFCs, PFCs and SF6 (total 0.03 W m–2) are not shown. Concentration-based RFs for gases can be obtained by summing the like-coloured bars. Volcanic forcing is not included as its episodic nature makes is difficult to compare to other forcing mechanisms. Total anthropogenic radiative forcing is provided for three different years relative to 1750. For further technical details, including uncertainty ranges associated with individual components and processes, see the Technical Summary Supplementary Material. {8.5; Figures 8.14–8.18; Figures TS.6 and TS.7}. Source: IPCC Summary for Policymakers Fig SPM.5

The IPCC reports discuss effects such as the increase in atmospheric water vapour as "responses" to the forcing, or feedback.

I'm out right now, and all day today. I won't be back for another 12 hours or more, but I thought it might be useful to get this article up now. I'll maybe do more on the subject later. Meanwhile, feel free to expand in the comments.


  1. As promised I politely posed what seems to me like a reasonable question to ask Willis/Willard. As far as I can tell I was first in the queue. I still haven't received an answer, no doubt because I'm still on the cutting room floor!


    I wish I knew Nick Stokes' secret!


    1. Jim:
      Nick seems to be tolerated there, maybe because he is polite and restrained in his responses, especially to Willis, and generally ignores the vitriol towards him.
      I ended on the "cutting room floor" yesterday after posting some stuff (graph of Arctic ice in Aug 1938 and longer-term one of ice extent) from sks.
      Obviously verboten.
      They were there but when I went back had been removed.

    2. @ Tony Banton

      I have an acknowledged limited undertsanding of the deep science/physics/maths of AGW, but when I read this post it seemed to me that Willis and Watts were asking Water Vapour to "pull itself up from its bootstrap" to become a "forcing"

      offering no physical mechanism to do so

      when I skimmed the WUWT posts I noticed you had use the exact same phrase !!!

      pseudoscience at its finest

    3. Tony - I am unfailingly polite, but the mere mention of actual Arctic data seems to guarantee a red card at WUWT!

      Which thread did your comment disappear from? Just in case I happen to have a historical record of the event!

    4. Jim:
      I'm confounded.
      Just been back ....
      And my post is back again!
      Oh, of course. Remove when the thread is "current" and stick them back later.

      Yes the denizens cannot wrap their tiny minds around how if WV increase is caused of itself, then the forcing that Willis (it'll be him not Watts) have "discovered" would feedback on itself ad infinitum until all the oceans had boiled away
      Amazing what the mind can believe when your science is the ideologically motivated kind.
      Anyway, they got their "love and kisses" from the particularly sycophantic ones (Janice Moore)......

      "… the increase in downwelling radiation over the period as calculated by … the increase in downwelling radiation over the period as calculated by the IPCC, with little corresponding change in temperature …
      is the knock-out punch to AGW.

      Game over.


      (“’em” are the climate hu$tler$’ scientists-for-hire )."

      So pathetic.

    5. Missed off the last bit of Moore's sycophancy....

      "We are so PROUD of you"

      Where's the sick-bag?

    6. Tony - I wasn't taking periodic archives of that one I'm afraid, and it doesn't look like anybody else was either.

      They've played that trick on me a few times however. By way of example:


      Be sure to read the comments too. There's lots of us down the WUWT "memory hole"!

    7. @ TB, what I notice when reading those WUWT threads, discounting the obvious sycophantic lunatics

      is that like all conspiracy theorists they never deal with the "elephant in the room" i.e. the bootstrap issue - they always want to go deep into the weeds, pulling maths equations by the dozen - right out of their backsides and
      generally obsessing over irrelevant details to make themselves look smart - the goal is simply to win a rhetorical argument

      911 Twoofers will spend days arguing the toss over chemical compounds of various bits of rubbish, the explosive properties of nano thermite, the shape of iron spheres blah blah, yet in reality never dealing with the obvious issues - basically, like the Whutters because they can't

    8. WUWT said they have not blocked me. It sounds like a "but that is not my dog"-type argument. I think that people like myself and others are in permanent moderation so your comment is not automatically posted. And if you comment is never approved, then it will never be seen. So comments are not "blocked" in a technical sense, even though the outcome is the same.

  2. It seems to me a person who has no qualification what so ever but i do understand maths that if you increase the temperature of the ocean on average then it will increase evaporation, if you increase the temperature of the atmosphere then the resultant clouds will not precipitate small droplets but larger ones.
    To put it simply higher temperature increase uptake of H2O and higher temperature means larger rain fall events.
    Look at rainfall from the Tropics to the temperate zones it is high tropics lower in temperate zones.
    Now to somehow say that water in the Atmos. is the major driver is forgetting why water in the Atmos is higher.
    Have i made a mistake here?

    1. That's right, John, at least as far as evaporation goes. It's a feedback.

      (I don't know about the large vs small droplets, but you could be right there too. Someone else might comment on that.)

    2. Higher temperature of the atmosphere means high up drafts which means the water droplets get larger until they overcome the updrafts and fall some times the sheer size of the ice falls as hail stones.
      Lower zones have smaller droplet size the tropics do have larger droplet size.

    3. "Higher temperature of the atmosphere means high up drafts..."

      The lapse rate is the most important thing regarding the strength of updraft - which means, relatively cooler air over warmer (wrt to an SALR ). The higher the WV content then leads to large droplet size held aloft by those updrafts.
      An extreme updraft combined with backing winds with height will induce tornadic activity.

    4. I think it is water vapor that is a greenhouse gas, not water droplets which are not vapor. I am sure water droplets are important but they do not act as a greenhouse gas.

      There is a physical formula that shows how much water vapor the atmosphere will hold on average as a function of average temperature.

      The way it was explained to me is an increase in rain events is because the average air circulation slows down because of global warming. A slower air circulation means that rain-bearing clouds will hang around longer in a given region thus you get more rain. It also means an increase in drought events by the same logic.

    5. Harry,
      I think it is water vapor that is a greenhouse gas, not water droplets
      Liquid water absorbs IR and at similar fundamental frequencies as the gaseous form. I see no reason why liquid, or indeed solid, water should not be a greenhouse, err, absorber. Indeed, I think this is nature of the positive cloud feedback. The profile of the absorption bands will be different, as the Wikipedia explains, because of hydrogen bonding and lack of rotational fine structure (gas molecules are free to rotate, liquid molecules are, by their very nature, constrained in a (fluid) lattice. For the GHE, the H-O-H bend is the most significant, since it co-incides most with trhe distribution of frequencies from earthlight.

  3. Some emitted compounds affect the atmospheric concentration of other substances.

    It includes contributions from all substances affected by that emission

    In other words, forcing up (higher temperature) causes a feedback of more atmospheric water vapour, and the combined effect is included in the chart below:

    Hmm.. Maybe I'm misunderstanding your point but I think this isn't right. Everything in the SPM paragraph is talking about things regarded as forcings. Where it talks about emissions affecting concentrations of other substances it's talking about atmospheric chemistry, such as oxidisation of methane, not things considered feedbacks to warming. It's the temperature change which affects water vapor, not CO2.

    the combined effect is included in the chart below

    The chart does not include the combined effect of forcing and feedback. Only the forcing.

    1. You may be right there, PaulS. I don't have time to check now. I'll have a look later on.

    2. Yes, Paul is right. The chart is forcings only. Given a warming of 1K and a planetary energy imbalance of around 0.7W/m^2, the combined forcing plus feedback is around 3.9W/m^2 (3.2 + 0.7). The chart shows a total anthropogenic of 2.3 W/m^2.

  4. That slope turns out to be 62.8 / TPW. At the average TPW value in Figure 3 of 29 kg/m2, this gives us a slope of 62.8 / 29.0 = 2.2 W/m2 increase in absorption per kg/m2 change in TPW.

    Uh, 62.8/mean(TPW) is not the same thing as mean(62.8/TPW), which is surely what they want here. Given that, according to the data they cite, TWP varies across the globe by an order of magnitude, that's not exactly a minor error.

  5. Nice to know that Watts has finally caught up with Arrhenius who figured out that warming would increase water vapour that then amplifies the effect of a CO2 rise.
    120 years ago.

  6. I agree with PaulS. I think the IPCC paragraph is talking for example about methane which also leads to higher CO2 in the end when it oxidizes.

    The radiative effect of increased water vapor is indeed a feedback. Note it is partially compensated by a decrease in lapse rate (moist air has a lower adiabatic lapse rate than dry air, and the lapse rate is what fixes surface temp vs the radiating layer near the tropopause.) all very well explained by IPCC for those who take the time...

  7. Thanks to PaulS and Arthur for pulling me up on one bit I wrote above, now corrected.The chart isn't the combined forcing with feedback, it's just the radiative forcing. The feedbacks are on top of that.

    (I took the time to read IPCC's AR5 Chapter 8, where radiative forcing, effective radiative forcing and other matters are discussed.)

    1. Sorry, I missed this comment and Arthur's when I responded.

  8. Thanks to Neville Bott for popping the question to Willis & Willard.


    "No answer!" is still the stern reply.

  9. Anyone else managed to download the code and data, btw? It consistently fails for me at 53%.

    1. Mostly CERES and TPW data, which explains the size of the file. Work of Willis is only some few lines of codes, with even a link to stackoverflow. He can thank the scientifics who bring to him open data, and internet geek who explain him how to write R code...

    2. *the scientists, *the internet geeks
      Sorry my english is very bad...

    3. What Olivier said. Some people at WUWT said they had trouble downloading the zip file. I didn't.

      BTW - I see that you need to register now to get RSS data. Seems a simple process, but you'll have to wait to get a confirmation email.

  10. What a sight those two must present for people entering the venue.

    Two 'Flat-Earthers' at a geology convention.

    Are they wearing sandwich boards and selling pencils from a cup?

  11. Willis Eschenbach justifying climate McCarthyism at The Conversation.


    1. All I can say is "well, he would say that, would he?"

    2. I thought for a minute that you meant that Willis had written and article for The Conversation (and wondered how he qualified). I'm relieved to find it's a few comments, filled with false equivalence :)

      Why don't deniers ever give examples? That's a rhetorical question. If they do, they are not examples. (Eg one commenter claimed that removing Bob Carter's adjunct professor status when he'd stopped contributing, was equivalent to stopping government research in an entire field of science.)

      Frankly, that lot are more than nasty. Willis wrote a similar article at WUWT, supporting a McCarthy-style purge of climate scientists. Disinformers don't like knowledge. Why anyone thinks that stopping science will stop global warming is beyond me. It can only make it worse, because decisions about how to address it will not be informed by the latest facts.

  12. My question is still invisible, and Neville's carbon copy remains unanswered.

    If I wasn't so busy extracting the Michael from the David and Judy Show at the moment I might have a go at the Willis and Watts Show too!


Instead of commenting as "Anonymous", please comment using "Name/URL" and your name, initials or pseudonym or whatever. You can leave the "URL" box blank. This isn't mandatory. You can also sign in using your Google ID, Wordpress ID etc as indicated. NOTE: Some Wordpress users are having trouble signing in. If that's you, try signing in using Name/URL. Details here.

Click here to read the HotWhopper comment policy.