Guest Post by Willis Eschenbach
Back in 2010, I wrote a post called “Prediction is hard, especially of the future“. It turned out to be the first of a series of posts that I ended up writing on the inability of climate models to successfully replicate the effects of volcanoes. It was an investigation occasioned by the oft-repeated claim from the modelers that the models are wizards at replicating volcanoes, such as this claim from Andrew Lacis:
There we make an actual global climate prediction (global cooling by about 0.5 C 12-18 months following the June 1991 Pinatubo volcanic eruption, followed by a return to the normal rate of global warming after about three years), based on climate model calculations using preliminary estimates of the volcanic aerosol optical depth. These predictions were all confirmed by subsequent measurements of global temperature changes, including the warming of the stratosphere by a couple of degrees due to the volcanic aerosol.
My research showed that contrary to the claims of the modelers, the models did a very poor job of replicating the effect of the volcanoes. In particular, they overestimated the amount of the global temperature change resulting from an eruption. I wrote these and subsequent results up in a number of following articles (list appended). Many people objected strongly to my results that showed the volcanoes didn’t have the huge effect claimed by the models.
As a result, I was pleasantly surprised to find an article in press at JGR entitled “Coupled Model Intercomparison Project 5 (CMIP5) simulations of climate following volcanic eruptions“. The paper is not yet published, but the Abstract says it all:
ABSTRACT (emphasis mine)
Key Points
• Large volcanic eruptions cause a major dynamical response in the atmosphere
• CMIP5 models are assessed for their ability to simulate this response
• No models in the CMIP5 database sufficiently represent this response
The ability of the climate models submitted to the Coupled Model Intercomparison Project 5 (CMIP5) database to simulate the Northern Hemisphere winter climate following a large tropical volcanic eruption is assessed. When sulfate aerosols are produced by volcanic injections into the tropical stratosphere and spread by the stratospheric circulation, it not only causes globally averaged tropospheric cooling but also a localized heating in the lower stratosphere, which can cause major dynamical feedbacks. Observations show a lower stratospheric and surface response during the following one or two Northern Hemisphere (NH) winters, that resembles the positive phase of the North Atlantic Oscillation (NAO). Simulations from 13 CMIP5 models that represent tropical eruptions in the 19th and 20th century are examined, focusing on the large-scale regional impacts associated with the large-scale circulation during the NH winter season. The models generally fail to capture the NH dynamical response following eruptions. They do not sufficiently simulate the observed post-volcanic strengthened NH polar vortex, positive NAO, or NH Eurasian warming pattern, and they tend to overestimate the cooling in the tropical troposphere. The findings are confirmed by a superposed epoch analysis of the NAO index for each model. The study confirms previous similar evaluations and raises concern for the ability of current climate models to simulate the response of a major mode of global circulation variability to external forcings. This is also of concern for the accuracy of geoengineering modeling studies that assess the atmospheric response to stratosphere-injected particles.
So it turns out to be even worse than I have been saying for a couple of years now. Not one of the models used by the IPCC was able to replicate the effects of volcanoes. The problem, as always, is that the climate is not dead. It actively responds to mitigate and alter the effects of a volcanic eruption, and the models are unable to replicate that active evolution of the global meteorology that occurs in response to the eruption.
It’s always nice to see other scientific studies backing up the results of my own research, particularly when I’ve taken lots of flak for the positions I have espoused. And it’s good to know that once again, WUWT has been publishing tomorrow’s science today …
w.
APPENDIX: My other posts on volcanoes:
Pinatubo and the Albedo Thermostat
Dronning Maud meets the Little Ice Age
New Data, Old Claims about Volcanoes
BEST, Volcanoes, and Climate Sensitivity
Zero Point Three Times the Forcing
The Nuclear Winter of our Discontent
The significance of the climate models volcanic forcing and why it is too large by a factor of 2 to 3 by my estimate is that the models need a large negative anthropogenic and non-anthropogenic aerosol forcing in order to maintain the large CO2 forcing, and produce output that has some (but not much) correspondence with reality.
As someone noted above, we know very little about what effects the different types of aerosols, size of particles, and multiple interactions actually have on the climate. That more work isn’t done measuring aerosol effects, is IMO scandalous, but the reason is obvious. Accurate values for aerosol forcings are going to invalidate the claimed CO2 forcing.
Willis, your science and your story-telling are both superb – now PLEASE write that book!!!
September 10, 2012 at 6:26 pm | Bart says:
“[ … ] the models are kluged together out of odds and ends without taking into account the complexity of the interactions between subsystems. [ … ]”
—————————-
One could describe them as the moose of modelling techniques?
I think what’s not being fully appreciated here is that in engineering and physics, we try to analyze systems under the impetus of sudden large transfers of energy (impulses) because this is the best way of describing the dynamics of the situation. If you can’t model the “finite impulse response” of the system you certainly don’t understand it and cannot model it in the presence of random noise.
The mathematics of this sort of thing is utilized by the electrical engineers in their finite impulse response (FIR) filters and is worth looking up if you’re interested in that aspect of modeling climate.
Philip Bradley says:
September 10, 2012 at 7:55 pm
Thanks, Philip. You got it in one. IF the climate sensitivity is as large as the modelers claim, then the known forcing changes from an eruption should cause a much larger response than actually occurs. That is is the fork of their dilemma.
w.
Excellent, Willis. Glad to see that whatever you have been saying about models, feedbacks and volcanoes etc. coming true.
Reblogged this on seyisandradavid and commented:
Nice work Willis on your enlightening articles, and I quiet agree with Bill that volcanoes might have a greater impact on sea ice conditions than has been previously thought.
Willis and Philip Bradley:
At September 11, 2012 at 12:27 am Willis writes
It seems appropriate for me to repost a comment I made in the thread at
http://wattsupwiththat.com/2011/08/02/aerosol-sat-observations-and-climate-models-differ-by-a-factor-of-three-to-six/#comment-711396
It is below.
Richard
**********
Richard S Courtney says:
August 2, 2011 at 6:46 am
Friends:
The article quotes Penner saying:
“The satellite estimates are way too small,” said Joyce Penner, the Ralph J. Cicerone Distinguished University Professor of Atmospheric Science. “There are things about the global model that should fit the satellite data but don’t, so I won’t argue that the models necessarily are correct. But we’ve explained why satellite estimates and the models are so different.”
Hmmm. Let us consider what we know about how the models incorporate climate sensitivity and aerosol effects.
None of the models – not one of them – could match the change in mean global temperature over the past century if it did not utilise a unique value of assumed cooling from aerosols. So, inputting actual values of the cooling effect (such as the determination by Penner et al.) would make every climate model provide a mismatch of the global warming it hindcasts and the observed global warming for the twentieth century.
This mismatch would occur because all the global climate models and energy balance models are known to provide indications which are based on
1.
the assumed degree of forcings resulting from human activity that produce warming
and
2.
the assumed degree of anthropogenic aerosol cooling input to each model as a ‘fiddle factor’ to obtain agreement between past average global temperature and the model’s indications of average global temperature.
More than a decade ago I published a peer-reviewed paper that showed the UK’s Hadley Centre general circulation model (GCM) could not model climate and only obtained agreement between past average global temperature and the model’s indications of average global temperature by forcing the agreement with an input of assumed anthropogenic aerosol cooling.
And my paper demonstrated that the assumption of aerosol effects being responsible for the model’s failure was incorrect.
(ref. Courtney RS An assessment of validation experiments conducted on computer models of global climate using the general circulation model of the UK’s Hadley Centre Energy & Environment, Volume 10, Number 5, pp. 491-502, September 1999).
More recently, in 2007, Kiehle published a paper that assessed 9 GCMs and two energy balance models.
(ref. Kiehl JT,Twentieth century climate model response and climate sensitivity. GRL vol.. 34, L22710, doi:10.1029/2007GL031383, 2007).
Kiehl found the same as my paper except that each model he assessed used a different aerosol ‘fix’ from every other model.
He says in his paper:
”One curious aspect of this result is that it is also well known [Houghton et al., 2001] that the same models that agree in simulating the anomaly in surface air temperature differ significantly in their predicted climate sensitivity. The cited range in climate sensitivity from a wide collection of models is usually 1.5 to 4.5 deg C for a doubling of CO2, where most global climate models used for climate change studies vary by at least a factor of two in equilibrium sensitivity.
The question is: if climate models differ by a factor of 2 to 3 in their climate sensitivity, how can they all simulate the global temperature record with a reasonable degree of accuracy. Kerr [2007] and S. E. Schwartz et al. (Quantifying climate change–too rosy a picture?, available at http://www.nature.com/reports/climatechange, 2007) recently pointed out the importance of understanding the answer to this question. Indeed, Kerr [2007] referred to the present work and the current paper provides the ‘‘widely circulated analysis’’ referred to by Kerr [2007]. This report investigates the most probable explanation for such an agreement. It uses published results from a wide variety of model simulations to understand this apparent paradox between model climate responses for the 20th century, but diverse climate model sensitivity.”
And, importantly, Kiehl’s paper says:
”These results explain to a large degree why models with such diverse climate sensitivities can all simulate the global anomaly in surface temperature. The magnitude of applied anthropogenic total forcing compensates for the model sensitivity.”
And the “magnitude of applied anthropogenic total forcing” is fixed in each model by the input value of aerosol forcing.
Thanks to Bill Illis, Kiehl’s Figure 2 can be seen at
http://img36.imageshack.us/img36/8167/kiehl2007figure2.png ]
Please note that the Figure is for 9 GCMs and 2 energy balance models, and its title is:
”Figure 2. Total anthropogenic forcing (Wm2) versus aerosol forcing (Wm2) from nine fully coupled climate models and two energy balance models used to simulate the 20th century.”
It shows that
(a) each model uses a different value for “Total anthropogenic forcing” that is in the range 0.80 W/m^-2 to 2.02 W/m^-2
but
(b) each model is forced to agree with the rate of past warming by using a different value for “Aerosol forcing” that is in the range -1.42 W/m^-2 to -0.60 W/m^-2.
In other words the models use values of “Total anthropogenic forcing” that differ by a factor of more than 2.5 and they are ‘adjusted’ by using values of assumed “Aerosol forcing” that differ by a factor of 2.4.
In summation, all the model projections of future climate change are blown out of the water by the findings of Penner at al.
Richard
Carl Brannen says:
September 10, 2012 at 10:03 pm
Slight correction: In the case of natural systems, you generally get infinite impulse responses (IIR). Finite impulse responses are generally the result of artificial manipulation in digital computers.
” Observations show a lower stratospheric and surface response during the following one or two Northern Hemisphere (NH) winters”
Like Willis, I find it good to see this fact getting recognition. I remember commenting in Willis’ “spot the volcano challenge” that I was able to identify several of the events correctly, not by looking for the global cooling that is supposed to follow but by spotting a couple of successive warmer than usual winters, which I had already noticed to be a typical “fingerprint” of major eruptions.
Yet another sign of some sanity creeping into published climate science.
Just to back Willis up here, climate science likes to pretend they have got the volcanoes right, but it is entirely 100% inconsistent with the theory in general.
All of it. From the temperature response to a given forcing, to the impacts on the Stratosphere and Ozone, to the temporal nature of the response.
At some point, someone has to entirely redo the theory based on volcano impacts on the climate.
How can any model get volcanic effects correct when no climate scientist has noticed the obvious domination of lower stratospheric cooling due to volcanoes.
The following graph shows the obvious boom and bust effect on LST (lower stratospheric temps)
http://robjmitchell.smugmug.com/Weather/weather-photos-08/i-bX2Hjwj/0/L/rsstschanneltlsgloballandandse-L.png
SO2 combines with water to form sulphuric acid droplets that initially absorb shortwave energy before being rained out. The Lower stratosphere is then left with less water vapour as it cant be replenished due to the temp inversion and subsequently cools.
Since stratospheric changes seem to precede the inverse changes to the troposphere it is quite possible the warming during the satellite age was driven by volcanoes!
This is a must read from the New Yorker, “The Climate Fixers”
“For geophysical scientists, though, Mt. Pinatubo provided the best model in at least a century to help us understand what might happen if humans attempted to ameliorate global warming by deliberately altering the climate of the earth.”
http://www.newyorker.com/reporting/2012/05/14/120514fa_fact_specter
Rob JM says: Since stratospheric changes seem to precede the inverse changes to the troposphere it is quite possible the warming during the satellite age was driven by volcanoes!
http://robjmitchell.smugmug.com/Weather/weather-photos-08/i-bX2Hjwj/0/L/rsstschanneltlsgloballandandse-L.png
compare to:
http://www.vukcevic.talktalk.net/Ap-VI.htm
http://i50.tinypic.com/2s12an6.png
Lower tropo warming (dT/dt) has been on the decline since 1995 as has volcanic activity in Vuc’s plot.
The last two surges in LT warming coincide with the recovery period immediately after the pluse in stratospheric temps. That would at least be “consistent with” your suggestion that volcanoes caused the warming.
Very good article. I always enjoy Willis’s take on things.
Congratulations, Willis, on seeing the future and reality a bit more clearly than most, and now having someone work very hard to discover the same thing… Still, it’s nice to have confirmation.
@Vukcevic:
They might share a common cause…
http://www.pnas.org/content/97/8/3814.full.pdf
Like lunar tide stirring molten earth…