From the University of Leeds and the department of real problems, comes this paper:
Natural aerosols, such as emissions from volcanoes or plants, may contribute more uncertainty than previously thought to estimates of how the climate might respond to greenhouse gas emissions.
An international team of researchers, led by the University of Leeds, has shown that the effect of aerosols on the climate since industrialisation depends strongly on what the atmosphere was like before pollution – when aerosols were produced only from natural emissions. The research will be published in the journal Nature on 7 November.
Professor Ken Carslaw, from the School of Earth and Environment at the University of Leeds and lead author of the study, said: “We have shown that our poor knowledge of aerosols prior to the industrial revolution dominates the uncertainty in how aerosols have affected clouds and climate.
“In order to better understand climate change, we need to turn our attention towards understanding very clean regions of the atmosphere – as might have existed in the mid-1700s. Such regions are incredibly rare now, but we are looking for them.”
Aerosols tend to increase the brightness of clouds, which would increase the reflection of solar radiation to space, thereby partially masking the climate-warming effects of greenhouse gas emissions. Firmly establishing the effect of aerosol-induced changes on cloud brightness is an important challenge for climate scientists.
In an assessment of 28 factors that could affect the uncertainties in cloud brightness, the researchers found that 45% of the variance comes from natural aerosols, compared with 34% for human-generated aerosols. (Aerosol processes, such as how quickly they are removed from the atmosphere, account for the remaining uncertainty.)
“Our results provide a clear path for scientists to reduce the uncertainty in aerosol effects on climate because we have been able to rank the causes for the uncertainty,” concludes Professor Carslaw.
The research was funded by the Natural Environment Research Council, the EC Seventh Framework Programme and the National Centre for Atmospheric Science.
Further information
The study, ‘Large contribution of natural aerosols to uncertainty in indirect forcing’, will be published in the journal Nature on 7 November 2013.
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In order to better understand climate change, we need to turn our attention towards understanding very clean regions of the atmosphere – as might have existed in the mid-1700s.
Might have? So they don’t actually know what they are looking for then? They’ll make it up as they go along or until they find something that fits the CAGW narrative?
From “the science is settled” to one bunch staring into the depths of the oceans and wondering if it is down there where we can’t see it, and another bunch staring into the sky and wondering if it is up there where we can’t see it.
At least they’re starting to agree that we can’t see it….
Just another english backwater college looking for funds.
More uncertainties, this time about aerosols.
Let’s assume the hypothesis is false, then there is still an utter failure to produce predictive results from the idea that CO2 is ‘the’ thermostat.
Let’s assume that the hypothesis is true, then it is a refutation of the idea that CO2 is ‘the’ thermostat. But it also indicates that the Thermageddon conclusion can only be reached by: Life doing what life does, and life doing it without aerosols.
Which leaves only two conclusions: 1) We must destroy life to save life. 2) Environmental controls are the essential cause of Thermogeddon. And so the environmentally ‘sound’ or ‘just’ notion, the policy recommendation, is to ban environmental controls on CO2 sources.
‘Just another english backwater college looking for funds’
Well, it’s a point of view . . .
We did not have the ability to put out Forrest fires in the old days as we do today. They had to burn themselves out over time or were rained out. How do they account for just that single item?
Another money pit.
Am I the only one that finds statements like “may contribute more uncertainty than previously thought” incredibly arrogant and just oblivious to the questions that thousands have been asking for decades? I don’t care if you admit your own misplaced certainty but please don’t drag the rest of us with you.
“Aerosols tend to increase the brightness of clouds, which would increase the reflection of solar radiation to space, thereby partially masking the climate-warming effects of greenhouse gas emissions.”
——————————-
Yet another study trying to explain away “the pause” vs properly questioning the CAGW hypothesis
There must be regions that are immune to present day atmospheric circulation… /sarc
It is far worse than we thought! The Apocalypse lost, and oh, to gain another one!
thereby partially masking the climate-warming effects of greenhouse gas emissions…..
partially masking…..oh?, so temps have only partially stopped rising
The Southern Hemisphere is relatively free of human induced aerosols, yet the mid 20th Century cooling took place in both Northern and Southern Hemisphere at the same time; an obvious indication that the cooling was not due to aerosols. Nonetheless, the mainstream climate community had to ignore this simple fact in order to make the theory of CAGW plausible.
No reason why they won’t do it again.
This is not climate science. It is algebra. Find the value for x (x=aerosols) that makes the CAGW theory fit the observations. The science has never been about testing the theory. The theory was assumed to be correct from the start. The science of man-made climate change has always been about adjusting the variables to fit the theory, including aerosols, GISS temperature adjustments, deep ocean temperatures and getting rid of the Medieval Warm Period. If an observation doesn’t fit, there must be a variable somewhere that will account for it. Right?
The one thing that these so called scientists ‘know’ is that their beloved CAGW theory can not possibly be incorrect.
“In order to better understand climate change, we need to turn our attention towards understanding very clean regions of the atmosphere – as might have existed in the mid-1700s. Such regions are incredibly rare now, but we are looking for them.”
Uh, did you look in the deep oceans to see if they are hiding with the heat?
🙂
It seems that about 70% of the earth surface doesn’t really have any sources of aerosols, or any history of ancient sources of aerosols for that 70% of the surface. No wonder they don’t know how much (if) man made aerosols change climate; (or not)
“A satellite image shows pollution over eastern China in February 2004. The pollution, consisting mostly of soot and sulfate particles, was created from coal and wood burning and persisted throughout the winter.”
People burn fires and use electricity in the winter especially. No spy satellite needed. Now go see what the Chinese army and submarines are doing, now that you are finished spying on people burning wood to stay warm.
Every week we get several papers adding to uncertainty while the IPCC becomes more certain since 1997. How many papers have come out since 1997 adding to “more than we thought?” Noble cause corruption at work me thinks.
Has AR5 got the customary admission that the LOSU of clouds is low and of aerosols very low (or words to that effect)?
JF
I have to say that this sounds a bit ridiculous – and likely ignoring the Elephant in the room with respect to clouds. I mean, the reflectivity of clouds is possibly affected by aerosols?, yeah, ok, perhaps it is, but the effects are likely minimal in the big scheme of things? – surely the amount of any clouds (and any variation of that amount) would be the starting point – i.e. water vapour? – which also happens to be a GHG. this seems like looking for the needle without even knowing the size of the haystack?
Aerosols reduce the albedo of clouds. Sagan’s aerosol optical physics wiz wrong.
Look at rain clouds – the high albedo is from the large droplets.
Dave: “… statements like “may contribute more uncertainty than previously thought””
Nah, it’s an awesome confession. eg. “There’s a possibility that knowledge will lower the probability of a priori conclusions.”
More known less known.
It’s just anther desperate attempt to point the finger at CO2….somehow. It never occurs to them that they have been led down the garden path…
It is just too difficult for alarmists to contemplate that atmospheric CO2 (due to its logarithmic effect) has a very negligible effect on global temperature, once above 300ppmv. If anthropogenic CO2 emissions have had a measurable effect on global temperatures, then please show us the empirical evidence.
@James Baldwin: the logarithmic effect is part of the scam: there is no net CO2 iR emitted from the Earth’s surface.
“Aerosols tend to increase the brightness of clouds, which would increase the reflection of solar radiation to space”
So it’s only a coincidence that much of the warming of the last century coincides with the time frame when we were cleaning up our atmosphere and getting rid of aerosols?