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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Mmmm, not quite. The thesis presented by the paper is that the satellite based forcings, which are negative, are 6X too large. The models are using the 1/6X forcings NOW. If it were to turn out that the satellites are correct, the models would, all other things being equal, wind up showing less heating. To preserve the current CAGW hysteria, it is necessary to convince us that the modeled forcings are somehow superior to the actual data. Sort of like modeling g to be 180 ft/sec/sec and trying to find out where the engineers went wrong when they keep getting 32.2 ft/sec/sec, plus or minus, when they drop things out the window.
I have to agree with others that this appears as though reality does not match the models, so reality must be wrong. Now it is not as simple as that, because we are comparing an estimate based on reality to models based on … something. Still, that estimate must be wrong, because the models must be right!
I’m a skeptic, so don’t rain all over me, but the way I read this is different than the way many people here are reading this.
What Penner seems to be saying is not that the Satellite data is wrong, or is being measured incorrectly, but rather that the equations that are used to derive the amount of radiation reflected by aerosols is incorrect.
So far, no one has addressed the SCIENCE of what Penner is actually saying, and as someone interested in the science, I wonder if someone who is qualified to do so could analyze whether or not Penner has a valid observation?
Well there is one thing that can be said with absolute certainty and both sides implicitly agree – the science is NOT settled. Policy makers, please take note.
Don E says:
August 2, 2011 at 11:03 am
Just as I suspected all along; burning fossil fuel causes global cooling after it causes global warming.
______
Actually getting closer to the truth, but just opposite. Burning things like dirty coal creates cooling before it creates warming, as CO2 will stay around far longer than black carbon or sulfates. But this is hard for some people to grasp…that things can have opposite effects over differing time spans due to the complex nature of climate. Volcanoes cool in the short term, but can warm in the longer term as once the aerosols are washed from the atmosphere, you still have the CO2. Good thing this is true, by the way, or the earth could still be locked in the “snowball earth” mode, where even repeated Milankovitch cycles couldn’t shake it out, and it took massive volcanic activity to create enough CO2 to bust it out of that mode.
R. Gates says:
August 2, 2011 at 4:54 pm
Good thing this is true, by the way, or the earth could still be locked in the “snowball earth” mode, where even repeated Milankovitch cycles couldn’t shake it out, and it took massive volcanic activity to create enough CO2 to bust it out of that mode.
—————————–
Before Snowball Earth, CO2 was about 10,000 ppm. How did all that ice build up? When it ended, CO2 was only 12,000 ppm – about 7% of the level needed to end the Snowball.
It was super-continent Pannotia covering the South Pole which resulted in the last Snowball. CO2 had nothing to do with it. This is the continental allignment right after the Snowball ended. Think about it, Antarctica times 20 – Albedo rises to close to 50%. When continental drift splits the super-continent up and spreads it out away from the South Pole, the Snowball ends.
http://astro.wsu.edu/worthey/earth/html/im-paleozoic/tectonics-cambrian-600.jpg
R. Gates:
Your post at August 2, 2011 at 4:54 pm says in total;
**************
“Don E says:
August 2, 2011 at 11:03 am
Just as I suspected all along; burning fossil fuel causes global cooling after it causes global warming.
______
Actually getting closer to the truth, but just opposite. Burning things like dirty coal creates cooling before it creates warming, as CO2 will stay around far longer than black carbon or sulfates. But this is hard for some people to grasp…that things can have opposite effects over differing time spans due to the complex nature of climate. Volcanoes cool in the short term, but can warm in the longer term as once the aerosols are washed from the atmosphere, you still have the CO2. Good thing this is true, by the way, or the earth could still be locked in the “snowball earth” mode, where even repeated Milankovitch cycles couldn’t shake it out, and it took massive volcanic activity to create enough CO2 to bust it out of that mode.”
*************
That is so wrong it is hard to know which parts to refute. A complete rebuttal would require several pages. So, instead, and as a start, I ask you to justify one of your assertions. In the improbable case that you can, then we can learn from you about another of them.
As a starter, please explain in a quantitative manner how volcanic CO2 emissions could have increased global temperature from any of the postulated ‘snowball Earth’ episodes when throughout each of those times of ‘snowball Earth’ – and before the asserted increased volcanism – atmospheric CO2 was tens of times higher than it is now.
Richard
Katherine says: August 2, 2011 at 6:32 am
Yeah, I noticed that, too. The idea that the pre-industrial area was “pollution-free” suits the perspective that all environmental ills are the result of rapacious modern capitalism. I think it is rather telling that Dr. Joyce Penner is the “Ralph J. Cicerone Distinguished University Professor of Atmospheric Science” – apparently history was not part of her training. The French author Jean Gimpel wrote a lovely book in 1976 called The Medieval Machine which diocumented the pollution problems of the Middle Ages. To say that she is “disingenuous” is a kindness.
Frankly this article makes no sense. Am I missing some inscrutible logic or does the author need to go back to school to study English?
Between this and the many “mitigation” efforts being undertaken to “cool the Earth’s fever” I would not be surprised of certain SOBs hastened the end of the interglacial.
SteveS, that has been a minor worry of mine also.
SteveSadlov says: August 2, 2011 at 8:16 pm
You might, if you haven’t already, really, really, really want to read to Jerry Pournelle’s (et al) “Fallen Angels” (http://www.webscription.net/p-137-fallen-angels.aspx) and (http://en.wikipedia.org/wiki/Fallen_Angels_(science_fiction_novel))
Uber:
At August 2, 2011 at 7:46 pm you ask:
“Frankly this article makes no sense. Am I missing some inscrutible logic or does the author need to go back to school to study English?”
In my opinion, the article is deliberately written in inscrutable language because the findings of Penner et al. are so damning to the cause of AGW. The article is a press release on a paper that reports a measured value of the the cooling effect of aerosols which Penner et al. obtained using satelites. This measured value is very different from that which climate models assume. This can only mean that the measurements are wrong or the models are wrong.
Findings like those in the reported paper have to be presented in a manner that seems to support AGW or they have little chance of getting published. So, the paper goes to great lengths to provide doubt to its own findings because a report that says the models are wrong would be unlikely to obtain publication. Hence, in the press release Penner tries to say her work is good but her findings must be wrong: she has to say that because it is what her paper tries to say. In this circumstance it would be strange if the press release were clear.
The implications of the findings of Penner at al. are explained in this thread by several posts.
These explanatory posts include those from
myself at August 2, 2011 at 6:46 am and August 2, 2011 at 8:52 am
Matt G at August 2, 2011 at 1:15 pm
D. J. Hawkins at August 2, 2011 at 2:59 pm
I hope this helps.
Richard
So the climate is more sensitive to aerosols than the models? Then the the other study blaming aerosols for the lack of cooling was wrong. That means that the climate is actually more sensitive, and that the increase in ‘missing heat’ should pretty much disprove the CO2 hypothesis by making the math untenable.
Ha, I see Richard Courtney beat me to it with a much more surgical explanation. Still, how can you just gloss that over? It’s mind boggling.
re John says:
August 2, 2011 at 6:19 am
Yes of course, John, but my main point was to point out how trivial total SO2 emissions are, at around 65 Million tonnes p.a. relative to the annual increase in atmopsheric CO2 of around 14 Billion tonnes. It is characteristic of climate scientists like Penner that they have little feel or common sense when it comes to numbers. I repeat my question, is it really possible as claimed by Kaufmann et al PNAS 2011 that the 65 MtSO2 could offset the warming attributed by them to 14 GtCO2? What is the underlying science to justify this claim? What lab experiments like those of Tyndall 1861 have Kaufmann et al and Penner done to verify their beliefs?
What is the current level of temperature suppression by aerosols?
As global sulphate aerosol levels are lower than 40 years ago and distributed differently around the globe, the temperature must have been suppressed less by them. So what net effect have aerosols had on the temperature record over the past 40 years? And how have they caused flat temperatures for the past 10 years as CO2 has continued to grow.
RDCII says:
August 2, 2011 at 4:23 pm
I’m a skeptic, so don’t rain all over me, but the way I read this is different than the way many people here are reading this.
What Penner seems to be saying is not that the Satellite data is wrong, or is being measured incorrectly, but rather that the equations that are used to derive the amount of radiation reflected by aerosols is incorrect……
——————————————————————
There is a total amount of reflected radiation leaving the earth that is measurable. If there’s more or less coming from aerosols the difference will be subtracted/added to albedo. Just a matter of distribution. EXCEPT the specific allocation will matter to the climate models. The modelers seem to feel safe saying they may get clouds wrong, but not aerosols. So those equations do matter and point taken.
The satellite measurements do not show any significant change in the total solar shortwave reflected, the total Albedo of the Earth (including clouds, dust, atmospheric molecules etc.) which is the important measure (rather than some small component of it).
There was a short-term increase in solar shortwave reflected (up to about 3.0 W/m2) during the two major volcanoes and then a small drop from 1993 to 1999 (ozone depletion?) which has since gone back up. The change over the whole period from 1983 to 2010 is basically less than 1.0 W/m2. Now we are just getting small wiggles from the ENSO’s influence on total cloud cover.
So all this recent talk about aerosols cooling us off (and in this paper which says the aerosol impact on clouds might be under-estimated), is meaningless.
The total Albedo has hardly changed in 30 years. There is some evidence that solar radiation reaching the surface has increased a little but this either contradicts the reflected shortwave measurements from the satellites or it says that the Sun’s radiance has increased slightly (also contradicted by the satellites) or it says that direct absorption in the atmosphere has declined slightly (ozone depletion from the volcanoes). On balance, we have to say that there has been a slight increase in the total solar radiation making it to the surface, a small positive number rather than a negative one.
I have been led to believe that aerosols tend to remain in their respective hemispheres unlike CO2,
http://www.barrettbellamyclimate.com/page29.htm
compares the satellite record of temperatures graphically latitude by latitude from1976 to 2006. The southern hemisphere seems to have warmed ~.1°C in that time. The northern hemisphere ~.6°C
So why hasn’t the southern hemisphere warmed from the CO2, while it is the northern hemisphere that is being shielded from warming by the aerosols?
Richard S Courtney says:
August 2, 2011 at 8:52 am
“Importantly, as I tried to explain, if you input the empirical data on aerosols obtained by Penner et al. then none of the models – not one of them – could emulate global temprature change over the past century.”
I am not commenting om Richard’s fine work but using it to add a point of my own.
I want to make the point that models are incapable of serving as a replacement for scientific hypotheses and that the idea that models can be revised and improved in the same way as a physical theory is a fiction. I want to make this point in the most fundamental way, right down at the level of basic logic.
Looking at Richard’s words above, I think it is clear that the empirical results obtained by Penner, the satellite data, require a revision in all of the models to bring them in line with past history as it has been modified by Penner. Penner refers to “the equations for aerosols” and the need to revise them. In doing so, she is treating them as if they were physical hypotheses that are “about” something and that imply a specific range of data. That is simply wrong.
Take the simplest case of a model, a linear programming model that is used to study distribution patterns for some large organization, such as the Pentagon, and that serves the practical purpose of assisting planners as they create new distribution sites. The equations in that model are not “about” the distribution patterns, the map of the world, or anything. They have no cognitive content whatsoever. Of course, changes can be made to them in hopes of improving the model but the only way that those changes can be evaluated for improvement is through the resulting changes in the output of the model. In other words, you have to make several runs and compare simulation to simulation. A simulation is just a string of numbers that is treated as a “state of the world” or some such thing. There is no basis for identifying some subset of that string with some subset of the mathematical equations or some part of the code. (Of course, there are always programmer’s hunches.) The same holds for more ramified models such as Penner’s.
As Penner goes about improving her model, all she can do is compare simulation to simulation until she finds a string of numbers that better fits the impact that she believes that aerosols should have. However, the changes that she makes in the “equations for aerosols” will be propagated throughout the model. To fully evaluate those changes, she would have to compare all the output of a simulation with all the output of the other simulations. (Is this necessary in practical terms? Of course not, we have programmer’s hunches. But that is not science.) And here we have found the crucial difference between computer models and scientific hypotheses. Except at the level of high theory, think CERN, physical hypotheses do have cognitive content and can be defined in terms of the observational results that they specify by implying them. In physical theory, one can work on the equations for aerosols in isolation from the rest of theory and independently of competing theories. That is not possible with computer models. The only way to revise a computer model is to revise the entire model through comparison of complete simulations. So, it should be no surprise that new observational data about aerosols would invalidate all existing models and require changes in all of them, changes that affect the entire model, not just a specifiable bit of code.
Julian Braggins:
At August 3, 2011 at 6:18 am you say:
“I have been led to believe that aerosols tend to remain in their respective hemispheres unlike CO2,”
That is true because aerosols wash out of the atmosphere in days so they lack time to spread from one hemisphere to the other.
And you ask:
“So why hasn’t the southern hemisphere warmed from the CO2, while it is the northern hemisphere that is being shielded from warming by the aerosols?”
That is because the aerosol excuse is nonsense. Reality does what it does and it has no regard for what climate models say it ‘should’ do.
The bottom line is that nobody understands how the climate system operates or behaves. In the absence of either of those understandings it is not possible to build a scientific model of the system or how it behaves.
However, it is possible to build a computer game that can be claimed to be a model of the climate system, and several people have built such computer games. They each differ from all the others, but there is only one climate system that it is falsely asserted they all emulate.
Richard
This paper is hard to understand, but basically it seems to be saying that modelled aerosol cooling effects are 3 to 6 times greater than measured aerosol cooling effects. Therefore, they conclude, the observations are incorrect. If the observations are correct, the 1940-1976 cooling cannot be explained by aerosols. Furthermore, if the observations are correct, then the sensitivity of climate to CO2 must be much smaller than is presently modelled, just like Spencer is arguing.
Is this a correct summary?
Richard S. Courtney writes:
“The bottom line is that nobody understands how the climate system operates or behaves. In the absence of either of those understandings it is not possible to build a scientific model of the system or how it behaves.”
Well said. That is the bottom line. And no one will know until climate scientists put away their computer games, do research in the field, and create some physical hypotheses which describe the natural regularities that they discover. Of course, the physical hypotheses must prove to be reasonably well confirmed over the years.
What is most needed at this time is a reliable system of measurement. Unfortunately, there is no international or national body that, at this time, has either the good sense or the political credibility to plan such a system and the many subsystems that it would require.
Douglas Hoyt:
Yes. You do provide a correct summary.
The implications of the findings of Penner at al. are explained in this thread by several posts.
These explanatory posts include those from
myself at August 2, 2011 at 6:46 am and August 2, 2011 at 8:52 am
Matt G at August 2, 2011 at 1:15 pm
D. J. Hawkins at August 2, 2011 at 2:59 pm
Richard