Study: ‘Climate change scientists must turn their attention to clean skies’

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.

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.

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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50 Responses to Study: ‘Climate change scientists must turn their attention to clean skies’

  1. UK Sceptic says:

    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?

  2. davidmhoffer says:

    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….

  3. “when aerosols were produced only from natural emissions”
    I understand that science tells us that the native Americans used to fire the forests every year all across North America in the years before the Puritans got there.

  4. Stephen Richards says:

    Just another english backwater college looking for funds.

  5. Bob Tisdale says:

    More uncertainties, this time about aerosols.

  6. Jquip says:

    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.

  7. Glenn Haldane says:

    ‘Just another english backwater college looking for funds’

    Well, it’s a point of view . . .

  8. ossqss says:

    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.

  9. Dave in Canmore says:

    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.

  10. Jeff L says:

    “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

  11. TomRude says:

    There must be regions that are immune to present day atmospheric circulation… /sarc

  12. JimS says:

    It is far worse than we thought! The Apocalypse lost, and oh, to gain another one!

  13. Latitude says:

    thereby partially masking the climate-warming effects of greenhouse gas emissions…..

    partially masking…..oh?, so temps have only partially stopped rising

  14. Jim Clarke says:

    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.

  15. JohnWho says:

    “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?

    :)

  16. george e. smith says:

    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)

  17. Zeke says:

    “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.

  18. Jimbo says:

    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.

  19. Julian Flood says:

    Has AR5 got the customary admission that the LOSU of clouds is low and of aerosols very low (or words to that effect)?

    JF

  20. Kev-in-Uk says:

    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?

  21. AlecM says:

    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.

  22. Jquip says:

    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.”

  23. Lil Fella from OZ says:

    More known less known.

  24. james griffin says:

    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.

  25. AlecM says:

    @James: the logarithmic effect is part of the scam: there is no net CO2 iR emitted from the Earth’s surface.

  26. MarkW says:

    “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?

  27. Derek Sorensen says:

    Looks like it’s out a day early: http://www.nature.com/nature/journal/v503/n7474/full/nature12674.html

    Large contribution of natural aerosols to uncertainty in indirect forcing

    The effect of anthropogenic aerosols on cloud droplet concentrations and radiative properties is the source of one of the largest uncertainties in the radiative forcing of climate over the industrial period. This uncertainty affects our ability to estimate how sensitive the climate is to greenhouse gas emissions. Here we perform a sensitivity analysis on a global model to quantify the uncertainty in cloud radiative forcing over the industrial period caused by uncertainties in aerosol emissions and processes. Our results show that 45 per cent of the variance of aerosol forcing since about 1750 arises from uncertainties in natural emissions of volcanic sulphur dioxide, marine dimethylsulphide, biogenic volatile organic carbon, biomass burning and sea spray. Only 34 per cent of the variance is associated with anthropogenic emissions. The results point to the importance of understanding pristine pre-industrial-like environments, with natural aerosols only, and suggest that improved measurements and evaluation of simulated aerosols in polluted present-day conditions will not necessarily result in commensurate reductions in the uncertainty of forcing estimates.

  28. Mike Jonas says:

    Jim Clarke says that the N and S both cooled in mid 20thC, so aerosols could not have been the cause. That should have been man-made aerosols. One thing that has always bothered me about the claim that the mid 20thC cooling was caused by aerosols is that nowhere have I seen it said that the aerosols had been measured. It has always appeared to be pure conjecture trying to explain away the failure of the then increasing CO2 to warm the planet. Or is there actual evidence?

  29. Latitude says:

    Zeke says:
    November 6, 2013 at 12:08 pm
    People burn fires and use electricity in the winter especially.
    ===
    ..and clear and burn forests for palm oil year round

  30. frosty says:

    “From the University of Leeds and the department of real problems”

    beverage moment, coffee out me nose and all, very pythonesque :)

  31. RoHa says:

    Looking for funds, of course, but the University of Leeds is hardly a backwater college.

  32. Aussiebear says:

    I might suggest Outback Australia. I am sure there are some places that even the Aboriginals did not walk or burn. As far as naturally occurring aerosols, I might suggest the Australia Blue Mountains and Australian Alps. They have a blue haze on clear days from the release of volatile oils from Eucalyptus trees. In fact the Blue Mountains are precisely named for that reason. Quite pretty actually from the overlook at Katoomba, west of Sydney, next to the Three Sisters rock formation.

  33. CRS, DrPH says:

    MarkW says:
    November 6, 2013 at 1:51 pm
    “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?

    Actually, that’s been the justification by some, including former DOE Sec. Stephen Chu, for “geoengineering” to solve the AGW problem (if it exists).

    http://www.technologyreview.com/featuredstory/511016/a-cheap-and-easy-plan-to-stop-global-warming/

    Heat missing in the abyss….searching for primordial clean air in a completely mixed atmosphere system….these people are so desperate, you can just feel it! Meanwhile, the Arctic sea ice extent is expanding nicely.

  34. Andrew says:

    Let’s cut through the obfuscation a bit:

    “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.”

    So we just *know* that even the cleanest air we know of *must* be dirtier now than in the mid 1700s. The fact that we can’t find anywhere on earth that is cleaner than places where people have polluted and then reduced their pollution substantially couldn’t *possibly* mean that the air can only get so clean.

    This doesn’t add to uncertainty. The aerosol history has long been essentially unknown and a useful tool for people who wish to fit models to data. What this really amounts to saying is that you really can’t justify huge increases in aerosols relative to ca. 1750. And if you can’t do that, you can’t justify a very sensitive climate. That should *cut* uncertainty on the high end.

  35. Janice Moore says:

    “like looking for the needle without even knowing the size of the haystack”
    (Kev in the UK at 12:50pm today)

    Precisely.

    Except, they know there is no real point to the needle search.

    Aaaaand, {next week} here they are…… the IMPORTANT DEPARTMENT Brigade. Where are they this week? They are at the Pacific Ocean. Let’s look over their shoulders and see (ssshhh, don’t disturb their deep thoughts) …. what….. they……… are doing….

    Another Sad Tale from The Haystack Files

    Important Scientist 1: {sitting at table on restaurant deck, sunny day on U.S. west coast} Would you look–at– that, ….. those children over on the dock…. they are — …. ??

    IS 2: Huh? They’re throwing rocks at a log out in the ocean and mostly missing it. Oh I’m just sure that is SUPER important — NOT. Are you done with the ketchup — YET?

    IS 1: Nope. (pours ketchup on 2’s head) Now I am.

    IS 2: Thanks for that, 1. (grits teeth, sotto voce: 3 months, 23 days, 10 hours, and 5 minutes until I get that Ph.D. and so-help-me…)

    IS 1: Those rocks are adding HEAT to the ocean (raises eyebrows significantly).

    IS 2 (not a member of the Fantasy Science Club, just doing what he has to do…): Yeah, right.

    IS 1: THEREFORE, rocks are the answer to the mystery!

    IS 2: (wiping ketchup off head, mutters: of what in the world IS inside your head?)

    IS 1: What?……. {silence from 2} … I thought so. YOU could never figure this out. Ha! But, I did! All that missing heat? It was stored in rocks…. then, thrown into the ocean by little kids……. then, the tide takes it down, and down, and down, aaand …… {rubs hands together gleefully} we will need at LEAST 100 million Euros to STUDY it!!!! IS 2! We’re rich!!!!

    IS 2: You’re serious.

    IS 1: {sneer} You just don’t have the credentials to understand such things. {talks if to a 3-year-old} If little kids throwing rocks into the Pacific Ocean is a problem…. then….. so are all marine vessels… . WE ARE TALKING MAJOR SHUT-DOWN, HERE. (GRINS) We will keep ALL ocean-going vessels in port unless they pay a “heat fee”. Oh, boy, oh, boy, oh —

    IS 2: {eyes wide — pretends sincerity} Okay. But, you and I will see none of those “fees.”

    IS 1: {looks left — looks right, drops voice} You will if you join the Team. Big bucks to say that kind of nonsense — even more, hush money to keep quiet…. don’t give them anything to blackmail you with, though, …. stay AWAY from that woman from the Cook Islands….. or you will get ZERO cash. Youneverheardmesaythis.

    IS 2: {pauses for 17 seconds….. then, winks} Rocks it is!

    IS 1: Rocks! Possibly reducing our previously underestimated uncertainty which may lead to something IMPORTANT! {wink — kah-ching — raises mug of CO2-free beer, heh}

    IS 2: {grins — clinks mugs} To rocks!

    ********************************
    “… the University of Leeds is hardly a backwater college.” (RoHa at 3:02pm today)

    True. If they keep stumbling along in a conjecture-drunken haze at their present rate, however, they will be there soon enough… .

  36. Janice Moore says:

    Mo-d-erator to the Rescue!

    THANK YOU!!!

    If I could give you a Grant (or about 2 million of them like IS 1 wants), I would!

    Gratefully,

    Janice

  37. Jm thanks for the laugh

  38. lee forward says:

    Aussiebear says:
    November 6, 2013 at 3:12 pm

    Except when those volatile oils catch fire- then it’s climate change

  39. Janice Moore says:

    You are welcome, JP. Thanks for letting me know you got a chuckle out of that.
    #(:))

  40. Pamela Gray says:

    Something is not quite right here. Take a look at the data for atmospheric aerosols:

    http://aerosol.ees.ufl.edu/atmos_aerosol/section02.html

  41. Janice Moore says:

    Sure smells fishy, Pamela Gray. While the link you provided says that anthropogenic aerosols account for roughly 13% of the total… . (and thanks for that very helpful information).

    The above, from the IMPORTANT DEPARTMENT says:

    … 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…

    They don’t even precisely define where the remaining 21%! is expected to come from. “Aerosol processes, such as…” is not only vague but incomplete. And such as__? And such as __???

    Wow. There really must be a LOT of money in this! How much would you have to be paid to, ……….. well, now, I realize that you wouldn’t take a nickel. Let me rephrase that… . How much money would it take to get some spineless “scientist” to make such a FOOL out of him or herself? Pitiful.
    ************

    btw: How is the academic year going, so far? I hope that your teaching is more of a joy than a pain. Glad you make time to post on WUWT when you can.

  42. Brian H says:

    Can the sats analyse smoke to see what fraction comes from burning dung? They might reveal some eye-watering information… Complete combustion in rocket stoves etc. would have resulted in more CO2, of course. Complete combustion of aerosols before they get away! What a concept.

  43. Mike Bromley the Kurd says:

    “In order to better understand climate change, we need to [insert appropriately vague subject here] as might have existed [conveniently before we worried ourselves sick over things] Such [evidence] are incredibly rare now, but we are [trying our damnedest to find new reasons to study nothing].”

  44. Kev-in-Uk says:

    Pamela Gray says:
    November 6, 2013 at 9:10 pm

    Yet another piece of the anthropogenic cause ‘puzzle’ that is shown to be a small portion of the actual natural scale. Lets call it 400/3000 anthro to natural – so basically, if the natural aerosols or fluctuated or rose by +/- 15% (for whatever reason, wildfires, dust, volcanoes, etc) – this would essentially swamp any anthropogenic effect?

  45. Kev-in-Uk says:

    Janice Moore says:
    November 6, 2013 at 9:53 pm

    of course it smells fishy – dead fish must release aerosols too! :)
    the thing about the natural/anthro scale issue is that they will have no idea how much natural changed in the past when looking for ‘info’ on the cloud albedo-aerosol connection to compare to todays aerosols! An absolutely cast iron reason for completely pointless and circular investigation and of course, grant funding!!!

  46. Roy says:

    Stephen Richards says:
    November 6, 2013 at 11:20 am

    Just another english backwater college looking for funds.

    What a snobbish remark! Only a fool would say that to be a good scientist you have to be working at one of a very small number of elite institutions, or that any scientist working at an elite institution is bound to be top-notch.

    Linus Pauling, the greatest chemist of the 20th century, studied at Oregon Agricultural College.

  47. Pamela Gray says:

    Human influence has possibly decreased aerosols. Anyone who has flown or driven across the United States can see how much soil is now bound by agriculture. It used to blow away. All you have to do is take a look at palouse soil to realize that dust was at one time at least, a HUGE part of the atmosphere. The palouse country in the SE section of Washington grows lots of fruits and veggies on soil that was blown there eons ago. And it is many feet deep. The original location of that soil is in a part of the country now covered with agriculture crops nearly year round thanks to irrigation.

  48. beng says:

    ***
    Aussiebear says:
    November 6, 2013 at 3:12 pm

    They have a blue haze on clear days from the release of volatile oils from Eucalyptus trees. In fact the Blue Mountains are precisely named for that reason.
    ***

    Same in the US — Blue Ridge and Smokey Mnts. No Eucalyptus, but forests generally emit hydrocarbons.

  49. Tom J says:

    “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.”

    What does he mean by “clean”? Me thinks a bias is peeking up over the ledge, hoping not to be seen. Then he twists over to, “as might have existed in the mid-1700s”. Now, the proverbial plot thickens. What occurred after the “mid-1700s” when those “very clean regions” had still existed? Industrialization? Is that the point? Were those preindustrial societies with their overlords and serfs at One with Nature? Did those One with Nature societies clear land for agriculture with slash and burn techniques only after industrialization, or did that exist prior? Did not the horses in use leave horse droppings or were they magical horses that existed without processing food? And, if they weren’t magical horses (unicornless unicorns), did they at least leave sweetly perfumed aromatic droppings that didn’t dry up and blow away in powder and cause respiratory ailments. Or did those dried droppings at least metamorphosize into useful talcum powder? Is this the same thing that happened with the dung fires that are in use today and probably were prior to the “mid-1700s”? Were they magical effervescent dung fires until industrialization after the “mid-1700s” turned them into lung disease causing stinky dung fires. Were those “very clean” Medieval cities, prior to the “mid-1700s”, leaving “very clean regions” of the atmosphere prior to the “mid-1700s” because they were burning magical ash free, ember free, soot free, odor free, smokeless wood? Did we lose that magic after the “mid-1700s” so that now we’re stuck burning natural gas instead of magic wood?

    Ah, but this scientist cleverly leaves himself an exit: “very clean regions of the atmosphere – as might have existed in the mid-1700s”. So if magical agriculture, and magical horses producing magical dung, and magical wood producing magically disappearing smoke never really existed one can employ the magical word, “might”, to magically slither through a hole and hide so as not to look supernaturally silly.

  50. Bruce Cobb says:

    They are grasping at fig leaves. Again.

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