Atmospheric Aerosols and the Death of Nature
Guest post by Dr. Patrick Michaels
Big news last week was that new findings published in Nature magazine showed that human emissions of aerosols (primarily from fossil fuel use) have been largely responsible for the multi-decadal patterns of sea surface temperature variability in the Atlantic ocean that have been observed over the past 150 years or so. This variability—commonly referred to as the Atlantic Multidecadal Oscillation, or AMO—has been linked to several socially significant climate phenomena including the ebb and flow of active Atlantic hurricane periods and drought in the African Sahel.
This paper marks, in my opinion, the death of credibility for Nature on global warming. The first symptoms showed up in 1996 when they published a paper by Ben Santer and 13 coauthors that was so obviously cherry-picked that it took me and my colleagues about three hours to completely destroy it. Things have gone steadily downhill, from a crazy screamer by Jonathan Patz on mortality from warming that didn’t even bother to examine whether fossil fuels were associated with extended lifespan (they are), to the recent Shakun debacle. But the latest whopper, by Ben Booth and his colleagues at the UK Met Office indeed signals the death of Nature in this field.
The U.K. Met Office issued a press release touting the findings by several of their researchers, and didn’t pull any punches as to the study’s significance. The headline read “Industrial pollution linked to ‘natural’ disasters” and included things like:
These shifts in ocean temperature, known as the Atlantic Multidecadal Oscillation or AMO, are believed to affect rainfall patterns in Africa, South America and India, as well as hurricane activity in the North Atlantic – in extreme cases leading to humanitarian disasters.
Ben Booth, a Met Office climate processes scientist and lead author of the research, said: “Until now, no-one has been able to demonstrate a physical link to what is causing these observed Atlantic Ocean fluctuations, so it was assumed they must be caused by natural variability.
“Our research implies that far from being natural, these changes could have been largely driven by dirty pollution and volcanoes. If so, this means a number of natural disasters linked to these ocean fluctuations, such as persistent African drought during the 1970’s and 80’s, may not be so natural after all.”
An accompanying “News and Views” piece in Nature put the findings of Booth and colleagues in climatological perspective:
If Booth and colleagues’ results can be corroborated, then they suggest that multidecadal temperature fluctuations of the North Atlantic are dominated by human activity, with natural variability taking a secondary role. This has many implications. Foremost among them is that the AMO does not exist, in the sense that the temperature variations concerned are neither intrinsically oscillatory nor purely multidecadal.
But not everyone was so impressed with the conclusions of Booth et al.
For instance, Judith Curry had this to say at her blog, “Climate Etc.,”
Color me unconvinced by this paper. I suspect that if this paper had been submitted to J. Geophysical Research or J. Climate, it would have been rejected. In any event, a much more lengthy manuscript would have been submitted with more details, allowing people to more critically assess this. By publishing this, Nature seems to be looking for headlines, rather than promoting good science.
And Curry has good reason to be skeptical.
“In press” at the journal Geophysical Research Letters is a paper titled “Greenland ice core evidence for spatial and temporal variability of the Atlantic Multidecadal Oscillation” by Petr Chylek and colleagues, including Chris Folland of the Hadley Centre of the UK Met Office.
In this paper, Chylek et al. examine evidence of the AMO that is contained in several ice core records distributed across Greenland. The researchers were looking to see whether there were changes in the character of the AMO over different climatological periods in the past, such as the Little Ice Age and the Medieval Warm Period—periods that long preceded large-scale human aerosol emissions. And indeed they found some. The AMO during the Little Ice Age was characterized by a quasi-periodicity of about 20 years, while the during the Medieval Warm Period the AMO oscillated with a period of about 45 to 65 years.
And Chylek and colleagues had this to say about the mechanisms involved:
The observed intermittency of these modes over the last 4000 years supports the view that these are internal ocean-atmosphere modes, with little or no external forcing.
Better read that again. “…with little or no external forcing.”
Chylek’s conclusion is vastly different from the one reached by Booth et al., which in an Editorial, Nature touted as [emphasis added]:
[B]ecause the AMO has been implicated in global processes, such as the frequency of Atlantic hurricanes and drought in the Sahel region of Africa in the 1980s, the findings greatly extend the possible reach of human activity on global climate. Moreover, if correct, the study effectively does away with the AMO as it is currently posited, in that the multidecadal oscillation is neither truly oscillatory nor multidecadal.
Funny how the ice core records analyzed by Chylek (as opposed to the largely climate model exercise of Booth et al.) and show the AMO to be both oscillatory and multidecadal—and to be exhibiting such characteristics long before any possible human influence.
Judith Curry’s words “By publishing this, Nature seems to be looking for headlines, rather than promoting good science” seem to ring loud and true in light of further observation-based research.
May God rest the soul of Nature.
References:
Booth, B., et al., 2012. Aerosols implicated as a prime driver of twentieth-century North Atlantic climate variability. Nature, doi:10.1038/nature10946, http://www.nature.com/nature/journal/vaop/ncurrent/full/nature10946.html
Chylek, P., et al., 2012. Greenland ice core evidence for spatial and temporal variability of the Atlantic Multidecadal Oscillation. Geophysical Research Letters, in press, http://www.agu.org/pubs/crossref/pip/2012GL051241.shtml
Allan MacRae:
In your fine post at April 13, 2012 at 3:39 am you say;
“So Charlson, Hansen et al ignored these inconvenient aerosol measurements and “cooked up” (fabricated) aerosol data that forced their climate models to better conform to the global cooling that was observed pre~1975.
Voila! Their models could hindcast (model the past) better using this fabricated aerosol data, and therefore (falsely claim to) predict the future with accuracy.”
Yes! That is exactly what I reported in my 1999 paper which I reference in my post that you are replying. My work used information that was provided by the Hadley Centre to assess how the Hadley Centre GCM was developed. And that was as follows.
1.
The GCM ‘ran hot’ (i.e. it showed much more warming over the 20th century than HadCRUT indicated had occurred in reality).
2.
The modelers postulated that sulphate aerosol from industry had provided cooling which negated some GHG warming in reality.
3.
The aerosol washes out of the atmosphere within days so its cooling effect would be near industrial activity (i.e. the postulated aerosol cooling and industrial activity would have similar spatial distribution).
4.
The magnitude of actual aerosol cooling was not (and still is not) known but this did not matter because its magnitude would have to equal the degree of excess warming indicated by the GCM if the postulate were correct.
5.
Therefore, a degree of aerosol cooling was input to the GCM
(a) with magnitude of cooling which forced the model’s indication of 20th century warming to match the observed warming
and
(b) the spatial distribution of the cooling was input to the GCM to emulate the spatial distribution of industrial activity.
6.
This was a sensible test of the postulate that anthropogenic sulphate aerosol cooling was the reason why the GCM ‘ran hot’; i.e. if the postulate were correct then the addition to the GCM of the postulated aerosol cooling would provide similar spatial distribution of warming to that observed in reality.
7.
But the modified model output indicated a very different pattern of temperature changes over the 20th century than was observed; e.g. the model showed most warming where most cooling was observed, and it showed most cooling where most warming was observed.
8.
This result was inconvenient because it disproved the postulate that aerosol cooling was the cause of the model having ‘ran hot’, and nobody could think of another possible cause of the model having ‘ran hot’.
9.
This finding would have caused scientists to reject the model, but the next IPCC Report was scheduled so the Hadley Centre shouted about the match of global warming indicated by the model and observed global warming over the 20th century.
10.
But this match was fixed as an input to the model and was NOT an output of the model.
Long after my paper about the Hadley GCM, in 2007 Kiehle (see reference in my above post) showed that all other climate models also ‘ran hot’ but by different amounts. And he showed that they each adopt the aerosol fix. But they each adopt a different amount of aerosol cooling to compensate for the different degree of ‘ran hot’ they each display.
This need for a unique amount of aerosol cooling in each climate model proves that at most only one (and probably none) of the models emulates the climate system of the real Earth (there is only one Earth).
Richard
Philip Bradley:
Your post at April 13, 2012 at 6:31 am crossed with my reply to Alan MacRae. Please read that reply because it says all that needs to be said in response to your post.
Richard
Richard S Courtney says:
April 13, 2012 at 6:42 am,
Very good comment and analysis, Richard.
Philip Bradley says: April 13, 2012 at 6:31 am
I’ll note that several comments above equate (claimed) absence of evidence with evidence of absence, which of course it’s not.
_____________
Hello Philip,
Contrary to your statement, the above comment shows evidence of absence:
Regards, Allan
Douglas Hoyt:
July 22nd, 2006 at 5:37 am
Measurements of aerosols did not begin in the 1970s. There were measurements before then, but not so well organized. However, there were a number of pyrheliometric measurements made and it is possible to extract aerosol information from them by the method described in:
Hoyt, D. V., 1979. The apparent atmospheric transmission using the pyrheliometric ratioing techniques. Appl. Optics, 18, 2530-2531.
The pyrheliometric ratioing technique is very insensitive to any changes in calibration of the instruments and very sensitive to aerosol changes.
Here are three papers using the technique:
Hoyt, D. V. and C. Frohlich, 1983. Atmospheric transmission at Davos, Switzerland, 1909-1979. Climatic Change, 5, 61-72.
Hoyt, D. V., C. P. Turner, and R. D. Evans, 1980. Trends in atmospheric transmission at three locations in the United States from 1940 to 1977. Mon. Wea. Rev., 108, 1430-1439.
Hoyt, D. V., 1979. Pyrheliometric and circumsolar sky radiation measurements by the Smithsonian Astrophysical Observatory from 1923 to 1954. Tellus, 31, 217-229.
In none of these studies were any long-term trends found in aerosols, although volcanic events show up quite clearly. There are other studies from Belgium, Ireland, and Hawaii that reach the same conclusions. It is significant that Davos shows no trend whereas the IPCC models show it in the area where the greatest changes in aerosols were occurring.
There are earlier aerosol studies by Hand and Marvin in Monthly Weather Review going back to the 1880s and these studies also show no trends.
Several commenters allege that the climate models “predict” but they do not do so. They “project” and this is a different concept.
Philip Bradley says:
April 12, 2012 at 10:39 pm
The prinicipal use of the charcoal was almost exclusively for production of high quality steel for weapons and armour.
I’m afraid you are wrong. Charcoal was the fuel used by blacksmiths. In pre-industrial Europe every village of any size would have had a blacksmith, usually referred to as a smith. Which is why Smith is the commonest name amongst people of English heritage.
______________________________
So what did blacksmiths do? They worked metal as stated. The question is how much metal (and for whom)
You are also missing the population (1850 had a population of 1.2 billion, in 1959 it was 3 billion and now it is 7 billion), and the fact of a switch to coal from charcoal in the 1800’s. It was not until the early 1900’s that iron and steel became cheap enough to be come common.
…..in 1850 British steel output was only about 60,000 tons.
Graph of UK steel production from 1870 to 1978: http://www.makingthemodernworld.org.uk/learning_modules/history/02.TU.02/illustrations/02.IL.14.gif
And there was also forced displacement and genocide such as the Highland Clearances Again the use of steel was not common among the “great unwashed”
An interesting view of the industrial revolution
Terry Oldberg:
At April 13, 2012 at 8:27 am you say;
“Several commenters allege that the climate models “predict” but they do not do so. They “project” and this is a different concept.”
Yes.
A prediction is useful, quantified and falsifiable.
A “projection” is useless, unquantified and unfalsifiable.
All scientific models predict. And they are all imperfect. But they are all useful.
Climate models don’t predict so they are merely computer games.
Richard
Richard S Courtney (April 13, 2012 at 10:17):
Right on! Also, in the regulation of a system it is predictions that are needed. For this purpose, projections are worthless. Thus, after the expenditure of 200 billion US$ on research, IPCC climatologists have produced nothing that would be of value in regulating the climate. Widespread confusion of predictions with projections has led many to believe these climatologists have produced something of value from the 200 billion US$ when they haven’t.
To my other comment showing the scarcity of iron before the modern age, I should have added “pin money”
More interesting stuff to add to the collection of weird knowledge.
Wang et. al say it’s naturally occurring African dust!!!
http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-11-00413.1 (pay walled)
“This suggests a novel mechanism for North Atlantic SST variability – a positive feedback between North Atlantic SST, African dust, and Sahel rainfall on multi-decadal timescales. That is, a warm (cold) North Atlantic Ocean produces a wet (dry) condition in the Sahel and thus leads to low (high) concentration of dust in the tropical North Atlantic which in turn warms (cools) the North Atlantic Ocean”.
“An implication of this study is that coupled climate models need to be able to simulate this aerosol-related feedback in order to correctly simulate climate in the North Atlantic. Additionally, it is found that dust in the tropical North Atlantic varies inversely with the number of Atlantic hurricanes on multidecadal timescales due to the multidecadal variability of both direct and indirect influences of dust on vertical wind shear in the hurricane main development region”
………………………………………
Whereas B.B.B. Booth et. al. say, Our findings suggest that anthropogenic aerosol emissions influenced a range of societally important historical climate events such as peaks in hurricane activity and Sahel drought.
They want us to believe anthropogenic aerosol do it all. ….emissions of which are directly addressable by policy actions.
http://www.nature.com/nature/journal/v484/n7393/full/nature10946.html
Piffle! What are they going to do? Turn the Sahara into a golf course!
Trouble is they don’t know how much dust there is! Or what sign the forcing really is!
A scaling theory for the size distribution of emitted dust aerosols suggests climate models underestimate the size of the global dust cycle
http://sitemaker.umich.edu/jasperkok/files/kok2011_pnas_scalingtheorydustpsd.pdf
“Our research implies that far from being natural, these changes could have been largely driven by dirty pollution and volcanoes. If so, this means a number of natural disasters linked to these ocean fluctuations, such as persistent African drought during the 1970’s and 80’s, may not be so natural after all.”
Um, Booth cannot speak/think clearly? Volcanos obviously fit within the cause category “natural”, can’t blame them on humans.
Interesting that he used the hedge “implies”, which headline writers will omit. Typical of media today, almost standard with news of medical research. (Sometimes the end of the article will quote the scientists’ caveats.)
“oman’s comment that the Nature paper works against the theory that CO2 is _the_forcer is appropriate. I have the impression that several alarmist recent papers also did so. Of course they usually blame humans regardless.
As for how Nature magazine survives financially, I’d look at the propensity of university libraries to subscribe (albeit not a huge number of libraries but many), and possibly advertising (marketing people are confused, often wanting to be seen to be supporting research). There may be many researchers who subscribe or at least purchase relevant articles, out of their research grants. I do not know the answer, have not seen the rag.
Ray C says:
April 13, 2012 at 1:34 pm
Wang et. al say it’s naturally occurring African dust!!!
http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-11-00413.1 ….
_______________________________________________
Good find!
And a bit more along the same line.
PDF: http://journals.ametsoc.org/doi/pdf/10.1175/BAMS-85-3-353
Marine and terrestrial biomarker records for the last 35,000 years at ODP site 658C off NW Africa
PDF: https://www.geo.umass.edu/people/postdocs/zhangpubs/Zhao-biomarker-ODP658C-OG00.pdf
Abstract
….Upwelling Radiolarian Index and the percentage of Florisphaera profunda), surprisingly indicates that the last glacial maximum (LGM) was characterized by warmer sea surface temperature (SST), weaker upwelling, and lower marine productivity, compared with the preceding older glacial and subsequent deglaciation periods. Of the terrigenous proxies, the mean grain size of the non-carbonate fraction and the terrigenous alkane content indicate that wind strength and aridity were high. The weaker upwelling at the 658 site during the LGM may have resulted from changes in the strength and direction of the wind systems and/or shifts in the position and geometry of the upwelling cell….
Another paper: (computer models)
Principal component analysis of the evolution of the Saharan air layer and dust transport: Comparisons between a model simulation and MODIS and AIRS retrievals
Sun Wong, Peter R. Colarco, and Andrew E. Dessler
PDF: http://geotest.tamu.edu/userfiles/216/wong06.pdf
Philip, your rebuttal is silly. When you look at a mediaeval economy, village blacksmiths spent by far most of their time on weapons and armour production. The only other large use of iron was in tools and implements, and these were NOT forged steel, which is the principal commodity requiring large amounts of charcoal.
Fine, double the estimate. It’s still an utterly trivial amount, as is your entire contention that charcoal burning was a significant source of aerosols.
have you guys seen what those folks at Union College are saying about Monckton?
See: http://www.concordy.com/article/opinions/april-5-2012/on-global-warming-cherry-picking-and-publishing/4321/
Jimmy;
Nobody here cares- so nobody will check your link- because WUWT is a science blog and, therefore, people here are interested in science (n.b. not smears).
Please return when yiou have something to say.
Richard
Looking through the print version that snail-mail brought today brings amazement at how adroitly they avoid saying where their aerosol data came from (darned if I could find it).
I just had to laugh at the summary article by one Amato Evan, earlier in the same issue, page 170, how a ‘well-known climate model..with up-to-date parameterizations of aerosols…’.
It must be right because it reproduced the well-known greenhouse warming.
(I can hear their knees popping with so many genuflections.)
Evan calls the Booth article’s results ‘compelling’, their model ‘state of the art’, with ‘many implications. Foremost.. is that the AMO does not exist…’Another implication .. swiings in Atlantic hurricane intensity might be…completely man-made’.
Gee, what did we do to keep hurricanes away from the US ever since Katrina?
It must be the shining noble governments of the peri-Atlantic countries and their assiduous suppression of aerosol emissions. Keep it us and we’ll never have another hurricane!
You might be interested to see that Ben Booth has commented on Judith Curry’s criticisms on my blog: http://allmodelsarewrong.com/how-to-be-engaging/#comment-1094
Tamsin Edwards:
Thankyou for that link. I read the conversation with ‘Ben B’ with interest.
I think it is a prime example of the fact that discussing BS does not reduce the smell of BS.
The AMO is observed in reality. A model may – or may not describe – the mechanism(s) of the AMO. And it may demonstrate that one such possible mechanism is the appearance of the AMO resulting from interaction of several effects. But a model cannot disprove the existence of the AMO or any other observed effect.
I think I will write a model which shows the Moon does not exist but merely looks like it exists. Do you think I can publish the results of running my model as evidence that the Moon does not exist?
Richard
Just to add WRT the persistent droughts in the 70s and 80s in Africa – if anyone would care to look up! the persistent experiments of cloud seeding off the west coast of Africa at the beginning of the rainy seasons. The scientists who conducted the studies claimed they were to blame for the droughts and subsequent famines during this period. I forget the name of the documentary but I am sure someone will have the information.
Good site – thanks
Tamino [free advertising deleted. Make your own arguments. ~dbs, mod.] has shown how the Chylek et al. paper that Michaels touts to rebut this Nature paper has its own very serious problems (and, he did this despite the fact that Chylek et al. not only don’t give their code but don’t even give a very detailed description of their analysis).