Bishop Hill Ball or aerosol?
Oct 7, 2013 Climate: Models The Economist has rather perspicaciously realised that aerosols have emerged from the Fifth Assessment Report as one of the most interesting talking points, and covers the area in some depth in this week's issue.
The IPCC report itself suggests that
There is high confidence that aerosols and their interactions with clouds have offset a substantial portion of global mean forcing from well-mixed greenhouse gases.
However, the tweets coming out of the Royal Society meeting last week suggested that scientists were in fact completely divided on this question:
Gavin Schmidt: How much aerosol is anthropogenic is still not sufficiently quantified!
Olivier Boucher: Boucher: no correlation of aerosol forcing and CS in CMIP5 ensemble
Olivier Boucher: Absorption optical depth for low amounts of aerosol is highly uncertain and the last great unknown in aerosol radiative effect
Olivier Boucher: We don't yet have a good handle on the amount on absorbing aerosol in the Earth's atmosphere
It's interesting to see scientists expressing high levels of uncertainty among themselves (albeit in a semi-public arena) but broadcasting great certainty to the public. It's a pity then that the Economist piece is helping this process along, with no sense of scientists continued difficulties with the subject.
Nor, alas, does the article make the connection between low aerosol forcing and low climate sensitivity; one comes away from reading it with the impression that we should expect more warming because the cooling effect of aerosols is less. As readers here know, in order to hindcast the past correctly, models either have to have low ECS and low aerosol forcing or high ECS and high aerosol forcing. Other things being equal, the evidence of low aerosol forcing is good news for the future.
Reader Comments (38)
Who needs peer review when you have Twitter?
Could this be the Higgs Boson of climate science?
So the previous enviro panic about CFCs caused this one?
If aerosols offset a substantial portion of forcing, then HOW could the deep oceans possibly be heating up? Does not one contradict the other?
I used the same title about the same subject on a blog post in 2010 - http://www.climate-resistance.org/2010/01/ball-or-aerosol.html about an article in Nature, which said,
Also, an interview in 2008 with Greg Carmichael...
http://www.climate-resistance.org/2008/04/black-and-white-aerosols-show.html
And Veerabhadran Ramanathan:
Nothing new here, of course. The point being that uncertainty about the roles aerosols has been a 'known unknown' for long enough that there can be no excuses.
It is, however, a very 'convenient' hypothesis to explain away inconvenient observations.
What a curious article! Why so much depth on that topic in a generalist mag? And To what purpose if not hindcasting low sensitivity? Every time I dip into the aerosol emissions controversy I can't see any real progress since the 1970s. And so with no consensus on aerosols how can there be an claim of consensus on CO2....
The traditional answer to the header question being: "Haven't you got anything that's good for both?"
It's not just that the effect of aerosols in the atmosphere is very uncertain. We also have a poor understanding of the amount and nature of aerosols emitted to the atmosphere. Aerosol emissions depend on the equipment used, its age and state of maintenance, and its operation. Furthermore, there is illegal burning of particularly wood and coal, both of which emit lots of aerosols.
@rhoda
Or the great not the 9 o'clock news Swedish chemists sketch.... Ball or aerosol? No I want it for my armpits. :-)
"Climate Scientists. Making it all up as they go along as usual.
'There is high confidence that aerosols and their interactions with clouds have offset a substantial portion of global mean forcing from well-mixed greenhouse gases.'
Its not sign of confidence at all but of desperation that they need to resort to ‘the dog eat my homework’ styles claims , as with the deep ocean claim . The need to find a reason why reality as failed to follow the models , and as they cannot admit the models were wrong , for that would go against AGW dogma . Means they rather desperately hunt around for other reasons why their claims of doom have total failed .
In normal science there comes point , when the actual data contradicts you , that you accept your theory is wrong in the first place. But then AGW is neither normal nor ‘science’
Looks like CERN have cracked it. Right on cue.
CERN’s CLOUD experiment shines new light on climate change
There was also this tweet from Josh:
If anyone doesn't know the reference in the thread title, follow the first link in Ben Pile's comment.
Should the title be plural?
I for one can't wait for the next IPCC report ... Perhaps temperatures will have gone into a noticeable decline by then =)
Much heterogeneous phase physics and chemistry is two dimensional. I recall one of the professors on my academic committee opining that we cannot properly observe and investigate it, by definition.
It therefore disturbs me slightly that Boucher thinks there is only one "great unknown" remaining in the aerosol radiative effect. Perhaps he is just referring to his "known-unknowns".
I think all climate scientists are a bunch of aerosols...
David Blake cited CERN's CLOUD experiment. However, the results look like bad news for Svensmark's theory because they question the importance of cosmic rays.
http://press.web.cern.ch/press-releases/2013/10/cerns-cloud-experiment-shines-new-light-climate-change
Then, using a pion beam from the CERN Proton Synchrotron, they found that ionising radiation such as the cosmic radiation that bombards the atmosphere from space has negligible influence on the formation rates of these particular aerosols.
Aerosol forcing is the wedge of cardboard under the current short leg of climate models. The models are trained by the past. So to get a good fit, parameterized variables like aerosol forcing are used to tweak or even crush, the model output. There is no observational science involved at all, just ad hoc playing with parameter values to get "the elephant to wiggle its trunk". Now this is starting to become visible and the scientists are being forced (sic) into verbal contortions to justify the modellers varying use of the aerosol parameters. Then the SPM politicians have turned these verbal gyrations into something that suits their case and logic and observational science are completely absent from their output.
The Economist concludes:
"The new [AR5] assessment reckons the net effect of aerosols is minus 0.82 watts per square metre of the Earth’s surface (ie, a cooling of that amount). In the 2007 assessment, the IPCC reckoned the cooling was larger: minus 1.2 watts per square metre."
So the effects of aerosols have reduced by about one-third over the past 6 years. Does that mean we should see an ECS reduction of similar sigh and magnitude?
Two can play at this game. If they can use the huge aerosol uncertainty to hand-wave away every departure from models versus reality then surely they could use exactly the same trick to fudge the solar-climate link which seems to be perfect from the beginning of time up to 1985. Et voila, no more need for argument from ignorance (ie we can't think of anything else to match up 20th century temps).
Of course if you were to utilise instead the widely-held belief among climate scientists that the Arctic is the place where manmade CO2 warming should be most obvious then you can still use the solar-climate correlation directly with no aerosol fudge because it is only just as warm there now as it was in the 30's. It's even one of the few places where we don't need to argue about urban heat island effects.
From Nature's article "Molecular understanding of sulphuric acid–amine particle nucleation in the atmosphere"
"Nucleation of aerosol particles from trace atmospheric vapours is thought to provide up to half of global cloud condensation nuclei. Aerosols can cause a net cooling of climate by scattering sunlight and by leading to smaller but more numerous cloud droplets, which makes clouds brighter and extends their lifetimes. Atmospheric aerosols derived from human activities are thought to have compensated for a large fraction of the warming caused by greenhouse gases"
"Amine emissions are dominated by anthropogenic activities (mainly animal husbandry), but about 30% of emissions are thought to arise from the breakdown of organic matter in the oceans, and 20% from biomass burning and soil"
"The Intergovernmental Panel on Climate Change (IPCC) considers that the increased amount of aerosol in the atmosphere from human activities constitutes the largest present uncertainty in climate radiative forcing2 and projected climate change this century. The results reported here show that the uncertainty is even greater than previously
thought, because extremely low amine emissions—which have substantial anthropogenic sources and have not hitherto been considered by the IPCC—have a large influence on the nucleation of sulphuric acid particles."
We have to thank the Indians for their cows and the Chinese for their pigs and their H2SO4 it seems.
"Olivier Boucher: Boucher: no correlation of aerosol forcing and CS in CMIP5 ensemble"
CS? What does CS stand for?
"If aerosols offset a substantial portion of forcing, then HOW could the deep oceans possibly be heating up? Does not one contradict the other?
Oct 7, 2013 at 11:19 AM | Unregistered CommenterOtter"
I am laughing out loud. Otter, the obvious answer is that aerosols do not interfere with the radiation that is intended for the deep oceans.
There is high confidence that UK will suffer blackouts this winter if it is severe.
http://www.telegraph.co.uk/finance/newsbysector/energy/10360751/Blackout-risk-this-winter-highest-in-a-decade-warns-National-Grid.html
Something more important for The Economist to ponder if this paper was attached to reality as it used to be when I read it.
Jeremy Poynton,
I took cs to mean climate sensitivity
"If aerosols offset a substantial portion of forcing, then HOW could the deep oceans possibly be heating up? Does not one contradict the other?"
The same reason that the oceans magically discriminate against human CO2 in favour of the massively larger amount it creates all by itself and the same reason that a warming sea becomes a carbon sink rather than a source in the first place. ie when they are stuck for an answer, the fairy story they produce as an excuse is never checked for coherence, science, logic, contradiction, observations or common sense. They seemingly don't need to because nobody in the media cares.
Oct 7, 2013 at 3:48 PM | Unregistered CommenterJamesG
I think you covered all the bases. Excellent.
"Amine emissions are dominated by anthropogenic activities (mainly animal husbandry), but about 30% of emissions are thought to arise from the breakdown of organic matter in the oceans, and 20% from biomass burning and soil"
Allow me to be first to call BS on that one. I reckon non-anthro organic activity to well outweigh the animal husbandry. Wild animals, birds, insects, plants, bacteria. All the things that make up biomass, land or ocean, saltwater marshes and deserts alike. Man and all his domestic animals don't get a look-in, in terms of relative mass. But it would not keep up the scare to say that.
Aerosols were introduced into the models to fit, retrospectively, the cooling in the 50s and 60s and still preserve the forecast of CAGW.
As Ben Pile's comment suggests this is the period in which this parameter is badly determined.
It has been pointed out recently that low values of CS in the models require negative ie unphysical values for optical opacity.
Aerosols reduce cloud albedo by inhibiting droplet coarsening. This mechanism accounts for the end of ice age amplification of Milankovitch tsi increase (biofeedback driven by phytoplankton), also much 80s and 90s warming (the real AGW).
Should the title be plural?
Oct 7, 2013 at 12:34 PM Messenge
I could be wrong but I guess the title is a reference to an old Not the 9 O'clock News sketch to which an unspecified Scandinavian man is buying a deodorant and the answer was "No, it's for my armpits"
As somebody else has mentioned today, the Bish has a nice line in tabloid headlines. However he's waaaay too level headed.
David Blake (Oct 7, 2013 at 12:26 PM): an otherwise interesting article, ruined by the desire to somehow, anyhow, find some human cause for the “problem”:
In other words… animals…
In other words… animals (the predominant source of protein). The implication is that, without humans, there would be lower emissions of amines (probably under the assumption that the grazing animals humans, erm, husband, would not be replaced by other grazing animals – despite historical evidence to the contrary). All of which very conveniently counteracts the heating caused by human-produced CO2.
So amines are predominantly anthropogenic?? Anybody know why those slippery things in the sea smell... fishy?
Are we to blame for the world's fish population too? Best eat the lot of them then - you know, for the planet's sake and all that.
Tiny CO2 ; thanks for the explanation - I thought perhaps the Bishop meant the aerosol thesis was a load of ball.
I think that, this is yet more desperate clutching at straws, if it ain't disappearing into the deep blue briny - it must be us and the amines cooling down the atmosphere - I mean the CAGW supposition.......... is right ain't it?
Yes, aerosols are a source of 'cooling' but more particularly prevalent as part of and because of volcanic eruptions, when aerosols SO2, HCL, HF and of course large volumes of dust and particulates - are diffused out and into the upper atmosphere.
But blimey, humankind, its animal husbandry, is somehow affecting the overall budget of gaseous emissions and thus somehow causing LESS Warming [ + industrial sources may play a minor part]? Yes indeed animals, zooplanktonic, all manner of fauna, flora - breaking down of amino acids - causes the production of amines and adds to the overall budget of outgasing but it is an enormous stretch to believe that man's efforts - man made aerosols - they play any significant role in countering the warming of the solar influence - it ain't man's fault.
When are they going to give it up?
amines are organically-fixed nitrogen.
wahoo. the economist is discovering the nitrogen cycle.
it doubled last year.
Doubling of marine dinitrogen-fixation rates based on direct measurements
of course it probably didn't really double. they just doubled what they thought about it
it shows the huge margins of error in the allegedly settled science.
The most interesting thing to me about the Economist article wasn't that overall aerosol forcing is less negative than before, but rather that the warming estimates of black carbon aerosols are higher. And that was before it was learned, just last month, that up to nearly half of black carbon in the Arctic is from a previously neglected source in Putin's opaque country, that of flaring of natural gas from oil wells in Siberia.
So in addition to lower climate sensitivity, we now have a bigger source for reducing warming, as the importance of black carbon in causing warming is now higher. It is a lot easier, and cheaper, to reduce black carbon, than to reduce CO2, when the CO2 growth is coming from places like China and India, which need the energy to grow.
To sum up: lower climate sensitivity, more targets for reducing warming that are cheaper and easier to do (not EASY, just easier, and better for public health as well). Break out the bubbly!