From the University of Michigan something I think Dr. Roy Spencer will be interested in as it is yet another case where models and satellite observations differ significantly. See the figure S1 at the end of this article – Anthony
Aerosols affect climate more than satellite estimates predict
ANN ARBOR, Mich.—Aerosol particles, including soot and sulfur dioxide from burning fossil fuels, essentially mask the effects of greenhouse gases and are at the heart of the biggest uncertainty in climate change prediction. New research from the University of Michigan shows that satellite-based projections of aerosols’ effect on Earth’s climate significantly underestimate their impacts.
The findings will be published online the week of Aug. 1 in the early edition of the Proceedings of the National Academy of Sciences.
Aerosols are at the core of “cloud drops”—water particles suspended in air that coalesce to form precipitation. Increasing the number of aerosol particles causes an increase in the number of cloud drops, which results in brighter clouds that reflect more light and have a greater cooling effect on the planet.
As to the extent of their cooling effect, scientists offer different scenarios that would raise the global average surface temperature during the next century between under 2 to over 3 degrees Celsius. That may not sound like a broad range, but it straddles the 2-degree tipping point beyond which scientists say the planet can expect more catastrophic climate change effects.
The satellite data that these findings poke holes in has been used to argue that all these models overestimate how hot the planet will get.
“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.”
Penner and her colleagues found faults in the techniques that satellite estimates use to find the difference between cloud drop concentrations today and before the Industrial Revolution.
“We found that using satellite data to try to infer how much radiation is reflected today compared to the amount reflected in the pollution-free pre-industrial atmosphere is very inaccurate,” Penner said. “If one uses the relationship between aerosol optical depth—essentially a measure of the thickness of the aerosols—and droplet number from satellites, then one can get the wrong answer by a factor of three to six.”
These findings are a step toward generating better models, and Penner said that will be the next phase of this research.
“If the large uncertainty in this forcing remains, then we will never reduce the range of projected changes in climate below the current range,” she said. “Our findings have shown that we need to be smarter. We simply cannot rely on data from satellites to tell us the effects of aerosols. I think we need to devise a strategy to use the models in conjunction with the satellite data to get the best answers.”
The paper is called “Satellite-methods underestimate indirect climate forcing by aerosols.” The research is funded by NASA.
PNAS Early Edition: http://www.pnas.org/content/early/recent
Joyce Penner: http://aoss.engin.umich.edu/people/penner
The University of Michigan College of Engineering is ranked among the top engineering schools in the country. At $180 million annually, its engineering research budget is one of largest of any public university. Michigan Engineering is home to 11 academic departments, numerous research centers and expansive entrepreneurial programs. The College plays a leading role in the Michigan Memorial Phoenix Energy Institute and hosts the world-class Lurie Nanofabrication Facility. Michigan Engineering’s premier scholarship, international scale and multidisciplinary scope combine to create The Michigan Difference. Find out more at http://www.engin.umich.edu/.
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You can read the full text of the paper here including the SI: http://www.pnas.org/content/early/2011/07/25/1018526108.full.pdf?with-ds=yes
This figure from the SI is quite interesting:
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Another Ian says:
August 2, 2011 at 1:59 am
And, as cementafriend’s post notes:
“CSG (coal seam gas) = very, very BAD
LNG (liquified natural gas) = better, mo’ greenie friendly
yet both are methane CH4″
Simple really
Good methane: (LNG) fairy scarce and controlled by big oil, and linked to oil price.
Bad methane: shale and coal bed methane, plentiful and spread throughout the world and more ameanable to market forces.
So the aerosol modeling is all eff’d up, they go back and forth at their convenience on whether more clouds cool the surfarce or warm it, then tell us the science is settled. Someone get a rope…
It will be interesting to see how much of the warming from 1975 – 2000 will have to be accredited to decreasing aerosols using their model.
““now its being cited as a source of light reflective aerosols that can explain cooling over the last 10 years.””
So suddenly 10 years ago, even though technology was probably gradually reducing the ratio of aerosols to CO2, aerosols started having a cooling effect… but aerosols had no affect before that, when there was some apparent warming ???
(even though that warming was probably mostly from removing colder temp records).
Something wrong with their logic there, I reckon.
Climate boffins need to learn the first rule of holes: when you’ve dug yourself into a hole the first thing to do is stop digging.
This would be H I larious if it weren’t so serious. One word for you (one acronym anyway), GIGO.
I thought field studies from 2004 showed that seasonal atmospheric brown clouds caused warming of up to half the amount attributed to carbon dioxide- at least on the synoptic scale. So aerosols cause tropospheric warming in addition to stratospheric effects that offset warming. Which effect is the more significant?
The University of Michigan just took a hit on their reputation with the publication of this research as did NASA for funding it!
If they are understating the impact of aerosols currently, which are a cooling factor, that means they are providing more cooling that previously thought, and thus blocking more warming than previously thought, meaning future warming will be higher.
Seems like nothing by wild eyed speculation. The paper is just another arm-wave to explain why the projected warming of 0.2C per decade is not happening. The paper seems to admit that the models don’t have it right, but still (surprise!) claims very high climate sensitivity by postulating even greater albedo increases due to sulfate emissions than the modelers have used. So long as people rely on speculation about aerosol effects instead of data on aerosol effects, there will be little progress confirming climate sensitivity. A good start would be considering Occam’s razor: the simplest explanation is that the climate sensitivity is just much lower than the models say… like about 1.4 – 1.6C per doubling….. no arm waves about extreme aerosol effects are then needed.
I believe that divergence of reality from warming projections will eventually drag climate science (kicking and screaming) to accept objective reality instead of the very-high-sensitivity paradigm that has been dominant for 25+ years… this paper seems to be just another in that long series of kicks and screams. I expect many more like it. As Thomas Kuhn noted, defenders of an existing paradigm are extremely resistant to contrary data; they have too much personal stake in the paradigm to be convinced by contrary information, no matter how solid that information may be. But data always trumps the dominant paradigm in the end, so the high-climate-sensitivity paradigm will ultimately fall. The only important question is if the paradigm leads to wasteful and counterproductive public policy before it is replaced.
This reliance on and belief in models seems to have got completely out of hand.
My understanding is that models are attempts to simulate real world processes so that, eventually, accurate predictions may be made. The process of developing complex models I would expect to be a long, tedious process, with continual refinements based on observations of real world situations followed by testing of each refinement. Only after showing that a refinement actually improves the model would it be “hard wired” into the model, otherwise it should be junked.
Given the chaotic and immensely complex nature of the earth’s climate system, I am astounded that climate modellers have the arrogance to believe that they have got it all right so quickly.
If I were a modeller (I’m not, the only models I make fly, although most eventually crash), I would be pleased with the opportunity to refine my model as new information comes to light, as with the study here, which is why I find it refreshing that Penner said “These findings are a step toward generating better models”.
But this raises the question – at what point should we have confidence that the models are right? I would suggest there is a high risk in using current models to drive economic and environmental policies given the discrepancies that seem to be highlighted almost daily.
An ‘academic’ who says that measurements should be discounted in favour of theory is a disgrace to all scientific academics. For honest academics not to comment on this foolery is not “academic courtesy”, it is cowardice… and it costing the rest of academia their previously honourable reputation.
Well they present a postmodern method!
“If the large uncertainty in this forcing remains, then we will never reduce the range of projected changes in climate below the current range,” she said. “Our findings have shown that we need to be smarter. We simply cannot rely on data from satellites to tell us the effects of aerosols. I think we need to devise a strategy to use the models in conjunction with the satellite data to get the best answers”
If theory doesnt fit meashurements fudge them with aerosols to fit. Thats what they say!
Be aware that they are using two great fudgefactors.
1. The history of preindustrial aerosols (uncertainty is enormus).
2. The feedback of the aerosols (Unsertanty is enormus).
Those two in combination with models can give you any answer you wish. Now they want to use these to fit their co2 hyposesis and “models” right and explain why meashurement is wrong!!!!!!!
Welcome to the postmodern pseudo science era! They went down to the deep oceans trying to find the missing heat that didnt work so now they are using the biggest fudgin factor in models instead. Well thats how “robust” the cagw pseudo scince is. What ever you do dont question the dogma or the models.
They really really are in deep shit because this study has some very easy detetactable contradicition to answer for. They have gone in to the masterlevel of fudgemanagement and they sat themselfes in a position where they have fudge managed to many strings that they made a big tangel of them all. The numbers of contradactions is increasing like an avalange.
Whats more intresting is real scince based on meashurement and the scientific method.
They will not be able to answer to the meashured differencebetween models shown by Spencer.
They havent taken the Svensmark theory to account. They havent understood the feedbacks from clouds and they almost criminaloly underestimated and neglected the suns influence.
How strange that they go back to the pre industrial age, why not go back to the 1930, one of the hottest periods ever. Wasn’t most of the western world burning COAL in millions of open fires in that period? Don’t they remember SMOG?
Steve Keohane says:
August 2, 2011 at 3:49 am
Apparently, overestimating the effects of CO2 leads to overestimating the amount of aerosols to counteract the first fantasy.
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Yep, nailed it. They all agreed on some virtual reality, believed it was reality and now have to adjust other objects to fit their view of reality. It is fascinating. My hope is we can preserve some of them for observation and study at some point in the future.
Who you gonna believe:
the models
or your lying eyes?
Could someone write a brief, non AGW polluted paragraph without double negatives to simply say what was found? I find this report essentially unintelligible. Please say:
1) what was believed before, regarding aerosols’ effect
2) what was actually found and its implication.
A fine example of the legal approach to science – if there is inconvenient data which you can’t ignore (i.e. the other side have already put forward) then try to obscure it with a complex scenario bringing in new theories to cast doubt on the data. About the same as casting doubt on eye witness testimony because the witness once had an eye infection.
“The data doesn’t fit the models, therefore the data must be wrong” – priceless!
No one is an expert, but everyone is playing “expert theoretician” with their favorite ideas, and refusing to heed the definitive evidence that makes a mockery of all of their theories. The Venus/Earth comparison I have been trying to get everyone to face and accept as fact, shows that the temperature-vs.-pressure profiles of Venus and Earth, when their different distances from the Sun (and only that difference) are taken into account, are essentially the same over the range of Earth tropospheric pressures (1,000 millibars to 200 mb). Not only does this mean there is no increase in atmospheric temperature with an increase in atmospheric CO2 (Earth has just 0.04%, to Venus’s 96.5%), i.e., no greenhouse effect, but the only effect of Venus’s planet-wide cloud cover is a slight cooling, of just a few degrees, and ONLY WITHIN the clouds themselves, not of the rest of the atmosphere outside of the clouds. So those thick clouds covering Venus, while reflecting much of the visible light from the Sun, do not affect the overall temperature profile, or the “climate” of the planet.
My analysis is extremely simple, but no one seems to be able to see its unavoidable consequences for the pretensions of every theory of atmospheric warming today. Scientists have simply been fundamentally miseducated about the real thermodynamics of planetary atmospheres, and they are miseducating the world with their ignorant, and incompetent, theories.
Somehow missed from the abstract – “Nevertheless, the AIE using ln(Nc) versus ln(AI) may be substantially incorrect on a regional basis and may underestimate or overestimate the global average forcing by 25 to 35%.”
To Tim Curtin (12:47 AM):
China emits a great deal of SO2, now. But the US and Western Europe emit comparable (smaller) amounts. Russia and Eastern Europe are also emit enough SO2 to matter, but they emit far, far less than they did when the USSR was in business. When the USSR collapsed, within 2 years there was a very large drop in SO2 emissions from Eastern Europe and the former USSR, because all the extremely inefficient and thus uneconomical enterprises went out of business.
The peak emissions of SO2 in the US was around 1974, at around 27 million tons per year. After the first oil embargo, we lost a lot of industry as well, and that has kept up ever since. In addition, the Clean Air Act amendments of 1977 and 1990 required utilities to reduce their SO2 emissions, which are now down to about 7.5 million tons per year, from a peak of over 18 million tons per year.
Western Europe had the same concern about acid rain as in the US, and has cut emissions by about the same amounts and now emits about the same as the US, give or take.
China is head and shoulders above everyone else, and the US is essentially in a three way tie for second with Western Europe, Eastern Europe and Russia, and up and coming India.
Ferdinand Engelbeen says:
A pollution-free pre-industrial atmosphere? Never heard of natural forest fires? Never heard of natural emissions of volatile organics (like terpenes) from trees, leading to secondary organic aerosols (SOA), causing the haze of the “blue” mountains? These are measured in the free troposphere in a ratio of 2:1 to larger than 10:1 compared to SOx, between 0.5 and 5.5 km altitude.
Maybe it’s pollution only if it’s man-made? And what do they consider “pre-industrial”? In the 1300s, pollution from coal burning was already a concern in medieval London. Supposedly by 1600, London’s coal consumption was over 50,000 tons a year. Earlier, there’s atmospheric Pb pollution from pre-medieval (Roman) mining that blew all the way to western Ireland. Then there’s copper smelting pollution during Roman and medieval times, “especially in Europe and China,” recorded in Greenland ice. What pollution-free pre-industrial atmosphere?
anopheles says:
August 2, 2011 at 1:29 am
Aerosols, the epicycles of the climate world.
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A slur on epicycles which were really a quite clever way to synthesize an inexplicable waveform using pre-seventeenth century math — which lacked almost all the tools we take for granted today. You could navigate using headings predicted from cycles and epicycles and end up where you wanted to go. On the other hand, using climate models in their current state for practical purposes seems likely to be something those without a prediliction for adventure might do well to avoid.
The claim that [thicker] clouds with smaller droplets ‘reflect’ more solar radiation is one of the key errors in climate science. You can easily prove it because when cloud droplets coarsen prior to rain, albedo increases, the opposite of what the aerosol optical physics in the models predict as you reduce optical depth.
Ask any glider pilot and he/she’ll confirm this second optical effect can cause temporary blindness. Sagan and Chandrasekar missed it so their maths is wrong.
The other error in the models is that ‘back radiation’ is (1) the artefact of a mathematical mistake made in 1922 and (2) is confused with Prevost exchange radiation, which does no work.
The fact that oxymoronic ‘climate science’ believes this junk science shows how bad is the level of basic physics in the subject!
So, this paper is also bunkum.
To Steven (4:52 AM):
Yes, it is indeed a good point that if increasing aerosols disguise alleged warming, then decreasing aerosols should increase it. There was a huge drop in worldwide SO2 emissions in the 1989-1991 period, with the collapse of the former USSR. Prior to that time, worldwide emissions had been slowly increasing. There are some articles in the press from a few years back, with titles such as “global brightening” and “global dimming” which do suggest that the warming post-Pinatubo may have had a lot to do with the reduction in sulfate formation from SO2 reductions, and, similarly, that the drop in warming, or steady temps, from after WW II through the mid 1970s had to do with the industrial ramp up in most developed countries after WW II.
I can’t judge whether they are right or not. But they back up your comment. Here is the Wikipedia link on global dimming (no, I don’t trust Wikipedia as a source of science, but this link shows that the subject has been discussed for a while):
http://en.wikipedia.org/wiki/Global_dimming
And here is a member of the warmist team arguing that Christopher Monckton’s suggestion that global brightening post 1990 was the cause for warming, not greenhouse gases, is incorrect:
http://www.skepticalscience.com/Could-global-brightening-be-causing-global-warming.html
In other words, the warmist camp, when it is in their interest, argues against the sulfate effect. In this case, if the sulfate effect is true and important, then the rapid warming of the 1990s was less to do with greenhouse gases and more to do with sulfate reductions.
Can’t have it both ways. We need science, uncorrupted science. And maybe the world wide suspicion of the games the hockey team, and the Climategate folks, and their acolytes such as Joe Romm and Gavin Schmidt have been playing will slow things down enough so that real scientists can be heard — whatever their ultimate findings may be.