Cloud cover is a major forcing, and uncertain, say researchers from the Hebrew University, US and Australia
Jerusalem, Jan. 26, 2014 – The warming effect of human-induced greenhouse gases is a given, but to what extent can we predict its future influence? That is an issue on which science is making progress, but the answers are still far from exact, say researchers from the Hebrew University of Jerusalem, the US and Australia who have studied the issue and whose work which has just appeared in the journal Science.
Indeed, one could say that the picture is a “cloudy” one, since the determination of the greenhouse gas effect involves multifaceted interactions with cloud cover.
To some extent, aerosols –- particles that float in the air caused by dust or pollution, including greenhouse gases – counteract part of the harming effects of climate warming by increasing the amount of sunlight reflected from clouds back into space. However, the ways in which these aerosols affect climate through their interaction with clouds are complex and incompletely captured by climate models, say the researchers. As a result, the radiative forcing (that is, the disturbance to the earth’s “energy budget” from the sun) caused by human activities is highly uncertain, making it difficult to predict the extent of global warming.
And while advances have led to a more detailed understanding of aerosol-cloud interactions and their effects on climate, further progress is hampered by limited observational capabilities and coarse climate models, says Prof. Daniel Rosenfeld of the Fredy and Nadine Herrmann Institute of Earth Sciences at the Hebrew University of Jerusalem, author of the article in Science. Rosenfeld wrote this article in cooperation with Dr. Steven Sherwood of the University of New South Wales, Sydney, Dr. Robert Wood of the University of Washington, Seattle, and Dr. Leo Donner of the US National Oceanic and Atmospheric Administration. .
Their recent studies have revealed a much more complicated picture of aerosol-cloud interactions than considered previously. Depending on the meteorological circumstances, aerosols can have dramatic effects of either increasing or decreasing the cloud sun-deflecting effect, the researchers say. Furthermore, little is known about the unperturbed aerosol level that existed in the preindustrial era. This reference level is very important for estimating the radiative forcing from aerosols.
Also needing further clarification is the response of the cloud cover and organization to the loss of water by rainfall. Understanding of the formation of ice and its interactions with liquid droplets is even more limited, mainly due to poor ability to measure the ice-nucleating activity of aerosols and the subsequent ice-forming processes in clouds.
Explicit computer simulations of these processes even at the scale of a whole cloud or multi-cloud system, let alone that of the planet, require hundreds of hours on the most powerful computers available. Therefore, a sufficiently accurate simulation of these processes at a global scale is still impractical.
Recently, however, researchers have been able to create groundbreaking simulations in which models were formulated presenting simplified schemes of cloud-aerosol interactions, This approach offers the potential for model runs that resolve clouds on a global scale for time scales up to several years, but climate simulations on a scale of a century are still not feasible. The model is also too coarse to resolve many of the fundamental aerosol-cloud processes at the scales on which they actually occur. Improved observational tests are essential for validating the results of simulations and ensuring that modeling developments are on the right track, say the researchers.
While it is unfortunate that further progress on understanding aerosol-cloud interactions and their effects on climate is limited by inadequate observational tools and models, achieving the required improvement in observations and simulations is within technological reach, the researchers emphasize, provided that the financial resources are invested. The level of effort, they say, should match the socioeconomic importance of what the results could provide: lower uncertainty in measuring man-made climate forcing and better understanding and predictions of future impacts of aerosols on our weather and climate.
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My take on it is, if he’s right about the Earth only emitting IR at 9-13 microns, then this nightmare of endlessly talking about “the pause” and looking at “trends in global surface temperature”…”arctic ice”…”NO Antarctica is losing ice MASS but gaining sea ice area”…”the models predicted everything [within massive uncertainty bars]…”no they didn’t they failed”…”oh yes they did”…”oh no they didn’t” and this whole unrelenting semantic ordeal that is “the climate change debate” can finally be OVER.
Because if CO2 doesn’t absorb/emit at 9-13 microns then that quite simply means all energy emitted from the Earth’s surface goes straight out to space as far as CO2 is concerned (H2O impedes it but CO2 literally couldn’t).
So IF the Earth only emits 9-13 microns IR and IF CO2 categorically does not absorb and emit in those wavelengths then we can all finally move on with our lives and stop screaming at each other about trends until we die.
I said something like this before:
Man can’t control nature but some men are using nature to try to control Man. (And make a few bucks in the process.)
Sorry should have added, my post is directed at Scarface.
I had a look at a nasa website ,
“Clouds on average cause cooling “
While they do work on modelling, we still do not have a quantitative assessment of the impact of clouds historically!
I, and others, have tried to work out the impact of changes in cloud cover on daytime temperatures, but I have yet to see a comprehensive analysis of global cloud cover changes and their impacts. The data is not there for the world, but it certainly is there for regions, and since CO2 is supposed to be global AND changes in a region like the Arctic or Australia or the peninsular Antarctic region are supposed to reflect global changes, one would think the analyses would bear significance for CAGW.
Never study what will upset the granting machines, a variant of the lawyer advice to never ask a question you don’t already know the answer to.
Re the greenhouse effect of CO2 – let’s don’t forget that on average there is 30 to 140 times as much water vapor in the air as CO2, and water vapor is about 8.5 times as potent a GHG as CO2 – in other words, about 250 to 1,400 times the effect of CO2. Kinda puts CO2 in perspective, doesn’t it? And that’s ALL the CO2 being pumped into the air – how about, fo openers, animal respiration, a huge multiple of fossil fuel CO2? ‘Nuff said. Man’s activities ain’t about squat when it comes to climate.
disappointed says:
January 27, 2014 at 11:42 am
In my mind it had better be removed.
———————————————–
I see several others who voice a similar thought, but doesn’t the great comment section rectify the need for removal with it,s diverse and open conversation that sheds light on reasons pro and con as to the value of the post?
The above post was meant for another page. Sorry!
Scientifically speaking, you might think it would be a good idea to try to understand clouds first, before focusing in on how aerosols might effect them. However that ignores the political imperative so present in science funding these days. It is much easier to get funding to study the effect of aerosols because that is a form of ‘pollution’, and there is the potential to turn up a ‘problem’ needing ‘urgent action’ and all the rest of the political carry on. This hits all the right buttons with funding agencies.
Although it is a fundamentally more important problem, trying to get funding to do the basic research required to simply improve our understanding of clouds as a natural process is much harder. Hopefully they’ll be able to sneak some basic scientific research on clouds in there while they look for the ‘problem’ with aerosols they need to find to satisfy their funders.
Steven Mosher says:
January 27, 2014 at 1:18 pm
meanwhile naysayers never build anything and say shit like man will never fly
————
Steven, while I agree with the general meaning of your post, it really only applies when the amount of detail lost in the model is insignificant to what’s being modeled.
Clouds aren’t insignificant, they’re a key part of the climate. Scientific estimates say that a 3% change in cloud cover can account for a major change in climate.
Add to that the fact we don’t know how oceans work either and take a look at a picture of our planet from outer space. You’ll see immediately how important clouds and oceans are.
http://earthobservatory.nasa.gov/IOTD/view.php?id=36019
I liked this: ‘Improved observational tests are essential for validating the results of simulations and ensuring that modeling developments are on the right track, say the researchers.’
Why those sillies. Whatever would make them think that?
=============
“””””…..wws says:
January 27, 2014 at 1:07 pm
Jerusalem, by William Blake:…..”””””
Thanx wws. Years ago I used to sing that song. (in elem school; not in ss-chool.)
I have the tune down pat. Never would have remembered the words.
Haven’t sung a note, since the Plasticine Age, but I still know that tune.
g
From the grauniad.co.uk no less.
http://www.theguardian.com/world/2014/jan/27/scandinavian-miracle-brutal-truth-denmark-norway-sweden
After being in this debate for a long time, I’d say I still haven’t seen anyone show me how CO2 does what it is supposed to do.
The only factual thing I’ve seen demonstrated is that CO2 is an efficient emitter of energy from the atmosphere to space at between 10 kms to 20 kms high where it is -53C or 220K. That technically means CO2 cools the atmosphere, not warms it.
Its not like I am incapable of understanding or even if that matters at all. Its just that NOONE has shown how it works. There are 2 papers which pop out a “forcing” number supposed based on Modtran and Hitran but they explain absolutely nothing. They just produce a number. And then there is the feedbacks, partially based on a real meteorology, but perhaps not, that seem to highly “tuned” to pop out further temperature increases along the lines of the theory as I have deconstructed it. Highly tuned, as in, change the feedback parametres by 25% and the whole thing falls apart.
But that is all there is to the story.
If someone has more to add in terms of explaining it, I’d sure appreciate it.
“…The warming effect of human-induced greenhouse gases is a given, but to what extent can we predict its future influence? …”
It would be a given if they could find its signature in the troposphere, until they do that it is a good theory not backed up by evidence?
That is my question by the way.
Steven Mosher says that a model which purports to describe the activity of the earth’s atmosphere without CLOUDS!!! is useful.
Steven, perhaps you should take a look at a satellite image of the earth any time of the year, day or night…I think you’ll find CLOUDS are quite a factor.
To take up your model car analogy, try thinking of a car with no hood, windscreen or front fender.. or maybe a car with no wheels. Yes that will come in very useful.
Regarding Steven Mosher’s analogy of a car, I think what we’re really missing here is an adequate model of it’s engine.
aljaz america in full Michael Mannian denier-mode:
26 Jan: Aljazeera America: Prominent scientist suing climate change deniers for libel
Speaking to Al Jazeera America just days after a court ruled that his defamation lawsuit against the libertarian think tank Competitive Enterprise Institute (CEI) and conservative news magazine National Review could proceed, Michael Mann, director of the Earth System Science Center at Pennsylvania State University, accused his detractors of resorting to old allegations that had been disproved time and time again…
But Mann told Al Jazeera that accusations made by his detractors had already been roundly rejected by the scientific community, stemmed largely from groups with a vested interest with the fossil-fuel industry and were part of a larger, ongoing effort to discredit climate-change research.
“The tactics climate-change deniers employ is based on the idea that if they can discredit one prominent scientist, they can discredit the entire environmental movement. They’re also trying to serve notice to other scientists who think about speaking out,” he said.
Mann’s lawyer John B. Williams added that the invidious nature of some comments from climate-change deniers was “sidetracking the real debate, which is science-based.”…
http://america.aljazeera.com/articles/2014/1/26/judge-allows-climatescientisttomoveforwardwithdefamationcase.html
REPLY: but with now only about 16,000 viewers, most of whom don’t care about climate, his appearance on AJA TV isn’t of any consequence – Anthony
“””””…..Mike Borgelt says:
January 27, 2014 at 2:00 pm
I haven’t seen any WUWT comment on this:…..”””””
An interesting post ; izzat Steve Goddard’s web site ??
The general gist of his post is something I have railed on for some time, but absent the info, on what IR astronomers see glaring them in their eyes (IRIs).
At the presumed 288 K earth surface Temperature (maybe 287 K), the calculated BB spectral radiance peak is at 10.1 microns (on spectral radiance per micron wavelength; not per wave nummer plots).
from stuff you learn in the 8th grade science, or maybe 4-H club science; you are supposed to have remembered that exactly 25% of all BB radiant energy lies at wavelengths shorter than the peak wavelength. Also, that only 1% of BB radiant energy lies below half the peak wavelength; and only 1% of the total energy lies above eight times the peak wavelength.
So for a 288 K BB, we have a 10.1 micron peak, and only 25% is below that, and the 1% limits are at 5.05, and 80.8 microns.
Now the 10.1 microns is in the so-called “atmospheric window”, but as the astronomer emeritus said, the 9.6 micron Ozone hole is in there too.
Now 10.1 microns may be the 288 K mean surface Temperature emission spectrum peak; BUT !!
at that Temperature (15 deg. C) the total radiant emittance is 390 W/m^2. Look for that nummer on Kevin Trenberth’s budget cartoon. So what is it like when the surface Temperature is 333 K or + 60 deg. C as in the equatorial deserts, where the earth is really cooling off at a high emission rate.
Well (333/273)^4 = 1.787 which now gives us 697 W/m^2 of cooling emittance.
But hang on . At that Temperature, the spectral emission peak has shifted due to Wien Displacement, and is now at 8.735 microns, and not 10.1.
Now even further into the window gap, and now even below the Ozone hole. Moreover, it is now further removed from the 15 micron CO2 degenerate (double) bending mode band; so CO2 is even less effective (but the spectral emittance at the CO2 band is still higer; but nowhere near 78.7% higher.
Of course, these equatorial deserts are as dry as a bone, so the atmospheric moisture content is way down; which is why the air Temperature crashes at sunset.; so the escape of this 78% higher emittance is further enhanced by the lack of water GHG effect.
Now the full calculation is a bit more complex. From your 4-H club you learned that the PEAK spectral radiant emittance increases as the FIFTH power of the Temperature; Not the FOURTH power.
So the narrower spectrum around the 8.7 micron peak, within the atmospheric window is actually more like 2.067 times the value per micron, at 288 K.
Which is why I have claimed for quite some time, that it is the tropical deserts and other location (UHIs as well) with their higher Temperatures, which are doing the planetary cooling chore; not the frozen wastelands (and seas) at the poles.
So what of those polar regions. Antarctica, we now know regularly gets down to – 94 deg. C , or about 179 kelvins.
So now the BB emittance spectral peak has shifted out to 16.25 microns; almost past the entire CO2 band. The total radiant emittance has dropped to only 14.9% of its 288 K value; or just 58.2 W/m^2. The shifted peak spectral emittance has dropped to just 9.3% of its 288 K value.
So the polar regions, have very little to do with the radiative cooling of the planet; even though CO2 develops its full GHG potential at those Temperatures. There’s very little radiative cooling going on at the poles for CO2 to have much influence there, on global cooling or warming.
So I checked my car’s radiator. It runs damn hot; hotter even than the Sahara. But it sure does cool like a Coors lite ( a near beer; same as Millers).
I notice several posts regarding the fact that atmospheric CO2 is about one in twenty five hundred molecules of the atmosphere.
Cube root of 2500 is about 13.6 . So a rather rough estimate, but if you are a CO2 molecule, then on average, it’s about 13.6 molecules from you to the nearest other CO2 molecule.
Do you get the feeling that you are alone in the universe ?? CO2 molecules don’t even know that others like them even exist. (in the atmosphere), so each one acts alone; by hisself.
Well so what ?
May I suggest that this paucity of CO2 molecules in the air is NOT a good choice for a hill to die on.
I’m typing this on a PC laptop full of silicon ICs. The density of deliberately inserted doping atoms in the silicon, (boron or phosphorous in older ICs) makes CO2 look like an ant’s convention at a picnic. Silicon IC dopant levels are WAY BELOW one in 2500. more like one in 50,000 to one in a million.
So all of the mayhem, that gose on inside your computer is caused by impurities way lower in abundance than CO2 in the atmosphere.
So forget that argument; it’s plain silly.
ladies and genltemen
I have to agree quite eagerly to what Georg E Smith is writing here.
What poisons theese debates first of all is the exteemly arrogant and ignorant and ugly religion of dia- lectic materialism, like for instance the Gen. Director and chief Engineer and Master Plumber and chief radiologist style of Cernobyl, all of them carefully head hunted and examined and plantet there from the Party. All from the same kind of background raisings at “The Peoples” Academy.
We notice here Quacky toxicology with very professional labels from the experts on things, and with no ideas of what is inside the bottles and the barrels or the atoms or molecules or conscepts, and how it possibly works.
Have you ever heard about a catalyst for instance and able to tell us what it is and how it works and in what conscentrations?
The very typical style of hat- tricks and of quackery is also to confuse surfaces and Volume and heat and temperature. Crooky and / or silly advocates and KADREmissionaries from the PARTY are further able to invent Perpetuum mobile stright vaway at any time and to launch and sell it.
Such as for instance finding and discovering or buying Kilovolts, and advocate and present it and sell it for kilowatts and even kilowatt- hours.
Thus also their eager and religious political propaganda against any kind of basic and of higher learnings. .
Mosher writes “You think the problem is black and white. No cloud formation= no model. Working scientists and working engineers dont necessarily think that way. They think.. what’s the best I can do, and then, how good is it, and then is it good enough for some purpose even if that purpose is limited.”
Good engineers know the limitations of a method. For example using a coarse cloud model might work ok up to a few hundred iterations (ie modelling weather) but will probably not be ok when iterating millions of times modelling climate.
There were many “flying machines” built before the Wright Brothers’ but none of them flew.
Actually, the story was the other way around. Models said that man could never fly. Wright brothers experiments proven the models wrong.
@cynical scientist
Otto Lilienthal was flying with hanggliders in Berlin long before the Wright Brothers, whoose problem was rather to get that propellar machine in order and mount it on a proper stearable gliding airplane. And they carefully designed and studied model gliding airplanes to find out.
Who inspired whoom ,who learnt from whoom and who stole it from whoom and who did first put things together and refined it further, and why would nobody believe it or buy it until.-…. that is quite a history.
The radiative forcing of all CO2 emitted since 1750 is 1.6 W/m^2. The uncertainty in radiative forcing of aerosol-cloud is -2 to -2.9 W/m^2 (Penner et al, 2003). We cannot conclude CO2 has a net forcing effect if we cannot model aerosol-cloud accurately. The net effect we are looking for is smaller than the uncertainty. The net forcing attributed to CO2 is speculative.
I read this as a kind of pre-emptive ritual obeisance at the altar of CAGW before getting down to business.
Smith!
Computer chips are solids. Atmosphere is gaseous. There is no analogy unless you are worried about your computer overheating!