I’m off to Italy for the next two weeks, starting tonight.
I suggested that the Erice seminar of the World Federation of Scientists have a session on Water Cycle Feedback, as this seemed to me to be the most important scientific issue affecting climate sensitivity. I had a couple of motives for suggesting this – first, it seemed to me to be the most important scientific issue involved in climate sensitivity; and second, I wanted to do something constructive for the seminar so that I would be invited back. It was a great visit last year and both my wife and I wanted to go again.
Fortunately, Zichichi and Manoli liked the suggestion and asked me to suggest terms and help with speakers. My description of the issue was:
The big question in climate is the “sensitivity” of global climate to doubled CO2. Estimates in AR4 GCMs vary from 2 to 4.5 deg C. Within the IPCC GCMs, the primary source of sensitivity uncertainty is cloud feedbacks, and, in particular, the shortwave response of low-level clouds (marine boundary layer). Despite a wide range of sensitivity within IPCC GCMs, IPCC GCMs do not necessarily span both sides of relevant characteristics of critical cloud types, e.g in tropical and midlatitude regions, simulations systemically yield clouds that are too optically thick, and not abundant enough in the mid-troposphere and in large-scale subsidence regimes.
Questions:
– IPCC AR4 pinpointed the largest source of intermodel variability between IPCC models to SW response of low-level clouds. What are the prospects for narrowing this source of uncertainty?
– IPCC AR4 identified several areas of systemic bias in cloud modeling GCMs e.g in tropical and midlatitude regions by simulating clouds generally too optically thick, and not abundant enough in the mid-troposphere and in large-scale subsidence regimes. Do these (or other biases) result in any material risk of under- or over-estimation of climate sensitivity? How could this be tested?
– are cloud (and other GCM) properties sufficiently constrained to confidently exclude the possibility of either very high climate sensitivity (above 4.5 deg C) or low climate sensitivity (under 2 deg C)?
– if not, which modeling components (cloud or otherwise) are mostly likely to result in a large enough systemic bias to yield either a higher or lower climate sensitivity? What steps can be taken to reduce such areas of uncertainty?
– Can paleoclimate and/or other indirect studies add any confidence to constraining climate sensitivity?
I suggested a number of speakers on both sides of the debate. My own hope was that I’d be able to learn something from the debate. The roster has ended up being over-weighted towards “skeptic” speakers: Lindzen, Arking, Choi, Kininmonth, Paltridge, but it is a blue-ribbon “skeptic” session. Invited but unable to attend: Peter Webster, Judy Curry, Andrew Dessler, Stephen Schwartz, Sandrine Bony, Tom Crowley. The invitations were only made in May and schedules had unforunately filled in for many people by then. The final session is:
CLIMATE & CLOUDS
FOCUS: Sensitivity of Climate to Additional CO2 as indicated by Water Cycle Feedback Issues
Chairman A.Zichichi – Co-chair R. Lindzen10.30 – 12.00
SESSION N° 9
* Dr. William Kininmonth
Australasian Climate Research, Melbourne, Australia
A Natural Constraint to Anthropogenic Global Warming
* Professor Albert Arking
Earth and Planetary Sciences Dept., John Hopkins University, Baltimore, USA
Effect of Sahara Dust on Vertical Transport of Moisture over the Tropical Atlantic and its Impact on Upper Tropospheric Moisture and Water Vapor Feedback.
* Dr. Yon-Sang Choi
Earth, Atmospheric and Planetary Sciences Dept., MIT, Cambridge, USA
Detailed Properties of Clouds and Aerosols obtained from Satellite Data
* Professor Richard S. Lindzen
Department of Earth, Atmospheric & Planetary Sciences, MIT, Cambridge
On the Determination of Climate Feedbacks from Satellite Data
* Professor Garth W. Paltridge
Australian National University and University of Tasmania, Hobart, Australia
Two Basic Problems of Simulating Climate Feedbacks
I’ll check in from time to time from Erice, but my blog attendance will be spotty. We’re going to be traveling in Italy for a few days on either side of the conference – in east Sicily around Siracusa for the next couple of days and Florence for a few days after the conference.
I’ve asked a few regulars to keep an eye on things while I’m away.
Climate Audit 
29 Comments
Great to start this topic off before the next IPCC is completed. Have a great trip and we know we will get an excellent report when you return.
Unfortunately, the “other side” has a habit of declining invitations for discussion, especially in public, if they perceive that the audience may be unfriendly or even (I^2 anyone?) ordinary free thinking people…
Hope you have a great trip, Steve!
The audience consists mainly of distinguished scientists from non-climate fields. Numerous Nobel winners have attended Erice conferences. Paul Dirac is a bit of a patron saint. The food, company and ambiance is great.
I wouldn’t put much significance on non-attendance decisions. Lindzen and the rest of this panel are all older scientists; the non-attendees are younger. You have more flexibility in August when your children are grown up. It may be nothing more than that.
Re: Steve McIntyre (#4), Okay, I didn’t know!
BTW:
I occasionally forget that our host, while being rather prolific and frankly amazing at all the work he does, is in fact human. How do you do it man? I’m impressed.
For the next couple of days expect in Siracusa Tmax around 32-33°C and Tmin (in the countryside) of 20-22°C.
There is a lot to see but the weather is ideal for the seaside. You can find a lot of white sand beaches going south from Siracusa to the southern tip of Sicily towards Portopalo di Capo Passero (where there is also a WMO weather station at the tall ligthouse on the hill). The best beach is at the natural reserve of Vendicari:
You jet-setting, CO2-belching, climate-auditing fool you! 😉
Sandrine Bony, I think. Steve: Yup
Roy Spencer is not attending?
I would be interested to know if Idso’s “Natural experiments” are still appreciated by your audience. Also what do they think of Luboš Motl’s and Nir Shaviv’s attempts? Have a good time!
Steve:My own interests tend to be with mainstream literature and I haven’t familiarized myself with any of the papers that you mention. I’m more interested in their views of mainstream literature.
Re: John G. Bell (#10),
Motl’s basking in the glory of a major experimental defeat for LQG (the primary competition for string theory) right now. I don’t think climate’s going to be on his mind for a while. Happy days in stringland.
I think I’ve never heard so loud
The quiet message in a cloud.
Bon Voyage.
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Minor correction: Johns Hopkins
Erice is beautiful (although the beaches below are not), the local food is excellent, and Zichichi is quite a character. Have fun.
If a doubling of CO2 is pretty well established that a non corresponding rise in temperature would occur without a positive feedback why do we attack CO2 and not the feedback that causes the AGW?
Re: Justin Sane (#15),
Don’t give them any ideas!
I wondered awhile ago, to severe critique, that not only do we not know the magnitude of the water feedback, but we don’t even know its sign. I wonder if it is variable, depending upon need, in a self-centering sort of way?
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I didn’t know you were starring in movies:
http://hotair.com/archives/2009/08/15/right-online-interview-not-evil-just-wrong/
Much talk in this interview about your efforts, starting at about the 20-minute-mark. I’m looking forward to this film.
So, admit it, you’re really off to Italy to make a new spaghetti western, aren’t you?
It is good to observe carefully, and at length, The Edge of the Sea.
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Steve, I surprised Petr Chylek’s name was not mentioned. As a scientist at Los Alamos National Lab, he has never taken funding from Big Oil or Big Coal and has published papers that have pleased both alarmists and skeptics. His work on climate sensitivity has focused mainly on lowering uncertainty from aerosols but his insight into the atmospheric processes would have made important contributions.
Re: Ron Cram (#19), I’m wondering what ever happened to his “International Conference on
Global Warming and the Next Ice Age”. I guess maybe there will be another one a couple of years from now?
An excellent idea, Steve. It really is a pity that the debate is likely to be a little one-sided. Can I suggest that you might like to consider adding at least one question to your list, which to me seems critical?
1) The Dessler and Zhang (2009) paper apparently shows from the 6 years of validated AIRS temperature and humidity data (2003 to 2008) a confirmation of a strong positive water vapour feed back. This conclusion, however, is partly founded on the use of the radiative kernels developed by Sodon et al which themselves are derived from models. The Lindzen (2009) paper infers a negative feedback by comparing total OLR from ERBE non-scanner data against temperature. Roy Spencer (March 2009 blog) confirms the magnitude of the IR response inferred by Dessler and Zhang, but argues that the key is probably in the SW response, which renders the total feedback negative. What are the arguments for and against these positions?
Have a great holiday!
Re: Paul (#22),
Nicely posed, but I think the water, in all its phases, feedback is variable, dependent upon need. There are so many components of the feedbacks that chaos, or a random walk between the two lines marking the ice ages and the in between times, reigns. I don’t know how the system is self-centering back and forth between those two boundaries, but it does.
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Re: Paul (#22), David Stockwell has been analyzing Dessler and thinks the method is unreliable:
http://landshape.org/enm/propagation-of-uncertainty-through-dessler/
Regarding Lindzen’s paper, his results are actually fairly similar to Spencer’s-in fact the feedback from LW (OLR) is actually near zero and the feedback from shortwave is strongly negative:
Click to access 2009GL039628-pip.pdf
Which he reckons is the result of either no water vapor feedback or the cancellation of the WV feedback by the Iris Effect. Considering the similarity of their overall results, one is left to wonder, what of Spencer’s positive LW feedback and much stronger SW feedback? The answer could be that Spencer is examining the whole Earth, while Lindzen’s ERBE results are for just the tropics. If so, the probable situation would be:
Tropics:
Iris and WV feedback operating
fairly strong SW negative feedback operating
Extratropics:
strong WV feedback operating
ice albedo feedback
very strong SW negative feedback
I’ll have to ask Spencer about the possibility of a regional analysis to see if in fact his and Lindzen’s results are compatible. But the above describes the situation that would need to be the case for that to be so, and may serve as a sort of hypothesis to be tested.
As for how good their methods are, let’s see what happens in the next few months. If they are seriously flawed, someone is bound to notice and wave the result like a bloody shirt.
Andrew: I have been enjoying these by D-Z Sun lately (links to pdf’s out there).
Tropical Water Vapor and Cloud Feedbacks in Climate Models: A Further Assessment Using Coupled Simulations, De-Zheng Sun, Yongqiang Yu, Tao Zhang
Radiative and Dynamical Feedbacks Over the Equatorial Cold-Tongue: Results from Nine Atmospheric GCMs D.-Z. Sun and T. Zhang, C. Covey and S.A. Klein, W.D. Collins, J. J. Hack, J.T. Kiehl, and G.A. Meehl, I. M. Held, M. Suarez
Radiative and Dynamical Feedbacks Over the Equatorial Cold-Tongue: Results from Seven Atmospheric GCMs, D.-Z. Sun and T. Zhang, C. Covey and S. Klein, W.Collins, J. Kiehl, and J. Meehl, I. Held, M. Suarez
It may be that there is a big difference between the tropics and elsewhere, but according to Sun all the models are hypersensitive to water vapor in the tropics and get clouds and lateral feedback wrong.
My comment on Dessler, a few paragraphs long, has been in review at GRL for 5 months. Have a comment back from Dessler. Still waiting.
Steve —
I hope your trip has been both productive and enjoyable!
In case you check in while you’re still in Florence, you might want to have a look at my page on David: A New Perspective.
Ciao!
So has anyone heard how the conference went? I’m assuming it’s over since Steve said they were vacationing on both ends of the conference.
I will be in Italy this weekend. When is this taking place? I would like to go. If it is over already can someone tell me where and when the next event for this will be. Thank you in advance for your time.
I believe, in regards to Paul#22’s post that there is so much that is considered fact when IN FACT there is such a small sample size when it comes to climate and the time between ice ages. The only real data we have about the planet earth and its climates is about 100 years worth. Not alot when you consider that the planet is almost 5 billions years old. Too much absolution in what is being said and reported today.
For example. If I meet someone for the first time and they are really sick. My only knowledge of that person is that they are sick. I didnt know them prior. Same as earth and its climate changes.