More aerosols, means more clouds, which means cooler temperatures. Now that we are cleaning up aerosols worldwide, this may explain why the Earth is getting slightly warmer – more sunlight reaches the surface
A paper published today in Science claims the transition from “pristine” to “slightly polluted” atmosphere at the beginning of the industrial revolution in the 18th century had a “dramatic aerosol effect [of increasing] clouds” over the oceans. According to the authors,
“transition from pristine to slightly polluted atmosphere yields estimated negative forcing of ~15 watts per square meter (cooling), suggesting that a substantial part of this anthropogenic forcing over the oceans occurred at the beginning of the industrial era, when the marine atmosphere experienced such transformation.”
By way of comparison, the IPCC alleged change in radiative forcing from CO2 [plus alleged positive water vapor feedback] since the beginning of the industrial era is +1.8 watts per square meter*, or 8.3 times less. According to an accompanying editorial to the paper, the authors “show that even small additions of aerosol particles to clouds in the cleanest regions of Earth’s atmosphere will have a large effect on those clouds and their contribution to climate forcing.”
*Per the IPCC formula: 5.35*ln(395/280) = 1.8 W/m2 at the top of the atmosphere [or only about 1.8* (1/3.7) = 0.5 W/m2 at the surface]
h/t to The Hockey Schtick
Smith et al. in 2004 finds that sulfur based aerosols, the kind that also get emitted from volcanoes, have been increasing since 1850, but have recently leveled off since about 1975…about the time that the US Clean Air Act really started kicking in (from updates in 1970) and other industrialized countries followed suit.
1850-2000: Methods and Results” -PNNL
Their paper:
Click to access PNNL-14537.pdf
From “Just Add Aerosols“: Science 6 June 2014: Vol. 344 no. 6188 p. 1089 DOI: 10.1126/science.1255398
The more carbon dioxide and other greenhouse gases in the atmosphere, the stronger the climate warming that results. Likewise, the more aerosol particles suspended in the atmosphere, the greater the ability of these particles either to scatter sunlight back to space and cool the planet or to absorb sunlight in the atmosphere, thereby warming the atmosphere while cooling Earth’s surface. However, not all such climate forcing processes depend linearly on the concentrations of their forcing agent. The climatic effects of aerosols are complicated by their interactions with clouds (1). On page 1143 of this issue, Koren et al. (2) show that even small additions of aerosol particles to clouds in the cleanest regions of Earth’s atmosphere will have a large effect on those clouds and their contribution to climate forcing.
The paper:
From aerosol-limited to invigoration of warm convective clouds
Abstract:
Among all cloud-aerosol interactions, the invigoration effect is the most elusive. Most of the studies that do suggest this effect link it to deep convective clouds with a warm base and cold top. Here, we provide evidence from observations and numerical modeling of a dramatic aerosol effect on warm clouds. We propose that convective-cloud invigoration by aerosols can be viewed as an extension of the concept of aerosol-limited clouds, where cloud development is limited by the availability of cloud-condensation nuclei. A transition from pristine to slightly polluted atmosphere yields estimated negative forcing of ~15 watts per square meter (cooling), suggesting that a substantial part of this anthropogenic forcing over the oceans occurred at the beginning of the industrial era, when the marine atmosphere experienced such transformation.
Editors summary: Invigorating convection in warm clouds
Atmospheric aerosols—tiny airborne particles—affect the way clouds form and how they affect climate. Koren et al. investigated how the formation of warm clouds, such as those that form over the oceans, depends on pollution levels (see the Perspective by Remer). Aerosols affect cloud formation in cleaner air disproportionately more than in more polluted air. Before the widespread air pollution of the industrial era, it seems, warm convective clouds may have covered much less of the oceans than they do today.
I’m sure this will be the lead story on ABC and NBC tonight.
Oh, sure, there were never any lightning initiated forest fires until man starting burning fossil fuels, nor did any pre-industrial people ever use wood/peat fires for cooking/heating. That’s why the atmosphere was ‘pristine’ then.
Paywalled.
Anybody knows if this is another computer model study or does it have real empirical data?
Another peed reviewed paper, no doubt.
More BS…
Uh, sorry, I did not see the link to the paper.
Hey get on the bandwagon. Don’t ally’all know that whilst the EPA has no idea on what is a natural load of airborne particulates, it is man’s job to clean the atmosphere….
Absolute rubbish.
This upsets the consensus applecart, whose view is that “we can’t think of anything but CO2 to explain the rise in temperatures since the industrial revolution.” Well, here’s something else.
When will these scientists do a study that has to do with understanding natural processes rather than “Man-made” processes?
Maybe not until the man-made “green” is cut off?
Well this is one study that may support the idea that humans can influence climate but the other way round LOL
Sounds like gradual removal of aerosols during the period 1980 to
1998 was the main cause of the warming, not CO2 increases. That
was when the automobile popultion switched over from cabureters
to much cleaner electronically controlled fuel injection. Once
the changeover was more or less complete, the warming stopped,
which is where we are today.
“For every action there is an equal and opposite reaction” . (I saw that someplace many years ago–I think it was the explanation on a desk toy my father had.) In any event , it now seems to me that for every paper that “proves” something about climate science, there is a paper that comes out that disproves it (or at the very least proves exactly the opposite). Given the alphabet soup that follows the names of all of these experts, I simply have no clue as to whom to believe anymore. The saving grace is at least I know what I believe, and at this juncture my beliefs appear to be as well founded as any presented by these scientific proofs offered up on a now daily basis.
This is ONE outlier paper that may be in fact correct. It makes sense that more particulates may induce more cloud formation (ie just look at clouds formations over volcanoes) and hence, cooling.Ironically it may be that both skeptics and warmist will agree on this one, except that warmists will have to now become coolists. LOLUnfortunately the outcome will be the same the need to reduce emissions will be called upon by both parties hahaha.
If it’s warming it our fault. If it’s cooling, it’s our fault. If they cancel each other out, and there’s no change, it’s our fault.
Roy Spencer says:
June 5, 2014 at 2:47 pm
If it’s warming it our fault. If it’s cooling, it’s our fault. If they cancel each other out, and there’s no change, it’s our fault.
==============================================
There seems to be something faulty about that reasoning. 😎
Yes, everything went down the drain when we introduced the vacuum cleaner.
Richard Lyman says:
June 5, 2014 at 2:37 pm
++++++++++++++++++++++++++
Newton’s Third Law – seems applicable to many things besides physics and engineering. Like politics, law and art even.
It’s worse than we can even imagine – and the question is: Just how much can we imagine?
Smith et al. in 2004 finds that sulfur based aerosols, the kind that also get emitted from volcanoes, have been increasing since 1850, but have recently leveled off since about 1975…about the time that the US Clean Air Act really started kicking in (from updates in 1970) and other industrialized countries followed suit.
Since China is currently burning more coal than the US is now with ‘pre-Clean Air Act’ scrubbers, and we are still using more coal than the 1970’s why does this show up? Does China coal not have any sulfur?
arthur4563 says:
June 5, 2014 at 2:36 pm
Sounds like gradual removal of aerosols during the period 1980 to
1998 was the main cause of the warming, not CO2 increases. That
was when the automobile popultion switched over from cabureters
to much cleaner electronically controlled fuel injection.
Between 1976 and 1990, pretty much the entire world, excluding the communist bloc, introduced catalytic converters.
A paper published today in Science claims the transition from “pristine” to “slightly polluted” atmosphere at the beginning of the industrial revolution in the 18th century had a “dramatic aerosol effect [of increasing] clouds” over the oceans.
A common misconception. When the Industrial Revolution occurred, coal replaced charcoal as the primary industrial fuel. Manufacturing charcoal ‘cooks off’ the volatile hydrocarbons into the atmosphere where they are an important factor in cloud seeding. I’ve seen charcoal being manufactured by the traditional method and it produces prodigious amounts of white smoke. Around the start of the Industrial Revolution, aerosols and cloud seeding volatile hydrocarbons likely declined substantially. IMO causing the end of the Little Ice Age.
An excuse for the lack of warming. Ha! I don’t believe they know anything, especially before 1850, Even 1850 I am skeptical of.
@DD More says:
June 5, 2014 at 3:00 pm
China may be burning lower sulfur coal. I did some work at a local PSEG plant a couple years back. The dropped about one billion $US on some back end technology for flue gas desulferization so they could burn US coal instead of the much more expensive very low sulfur product they were getting from Indonesia. It was nasty stuff too; constantly spontaneously combusting in the pile. There was always a fire visible on the coal pile somewhere.
It may also be the case that the Chinese power plant technology is not as primitive as folks generally assume. If I was shelling out perfectly good yuan for a new power plant, I’d like to know it was squeezing out every possible kilowatt per ton of fuel that it could.
I’m with Billy Liar (June 5, 2014 at 1:05 pm) and others. Pristine – what a joke.
Some climate scientists have blamed aerosols for the current lack of warming. Is there any evidence that aerosols have increased since the 90s?
Oops–what I should have said above was:
This upsets the consensus applecart, whose view is that “we can’t think of anything but CO2 to explain the rise in temperatures since the Seventies.” Well, here’s something else—aerosols.
Smith et al. in 2004 finds that sulfur based aerosols, the kind that also get emitted from volcanoes, have been increasing since 1850, but have recently leveled off since about 1975…about the time that the US Clean Air Act really started kicking in (from updates in 1970) and other industrialized countries followed suit. Thanks DD More….
I was pretty sure I’d seen this same idea presented about ten years ago. Made sense then….still does.
Dr Spencer – when will we see your numbers for May? I like your blog and look forward to this time every month. Keep up the good work.
Isn’t this theory contradicted by steady rise of albedo since 1997, despite steadily falling aerosols? http://wattsupwiththat.files.wordpress.com/2007/10/earth_albedo_bbso.png
I’ve read the paper. It is based on extrapolation from MODIS and CERES data from 2007, and they have their own microphysics model TAU-CM. One of the weaknesses, which they kind of acknowledge, is that they don’t really know if the pre-industrial air was “pristine”. And of course, they are working in cloud matters where modelling is known to be difficult.
The figure of 15 W/m2 is local, and so can’t really be compared to a global GHG forcing. In fact, they say there are substantial parts of the oceans that are still “pristine”. They show this map of AOD distribution.
It’s not obvious that industry is the main issue. The hotspot seems to be Africa.
Translation:
The Clean Air Act is at least partially responsible for the halt in Global Cooling in the 1970s and for a substantial part of the Global Warming of the 1980s and 1990s.
This may be a New Paper. It might even have New Data.
It is NOT a New Idea.
I recommend the authors look at any collection of Matthew Brady Civil War photographs to see the phenomenal visibility extinction in almost all the images. Methinks their numbers are just a tad low back then.
REPLY: Pat a lot of that had to do with UV sensitivity of photographic plates, UV filters had not been invented yet.
http://en.wikipedia.org/wiki/Photographic_film
-Anthony
If any of the readers of this blog actually got out of their mother’s basement and travelled to China or India, they’d see for themselves the megatons of sulfur and aerosols that are pumped into the atmosphere everyday. When clean air controls are introduced in these countries as they inevitably will be, we’re all screwed.
New? This concept was belched out by Thomas Wigley two decades ago and it was his creative explanation for the dip in global temperatures that occurred following the hot 1930s and 40s. The dip in temperatures up to the late 1970s was always a conundrum for our hardy global warriors since fossil fuel use shot up in the 1950s right while global temperatures declined. The solution: aerosols from industrial pollution that masked the otherwise warming which then magically appeared on schedule in the 1980s following pollution controls. Wigley was the employee of the unfortunate (for, as he would later insinuate, having hired him) Hubert Lamb who, I believe, founded the CRU at Margaret Thatcher’s request (I may be wrong about some of this). Reid Bryson, of the Univ. of Wisconsin, Madison, was a friend of Hubert Lamb’s and formulated the idea of industrial aerosols having a cooling influence on the atmosphere. Bryson, however, was never a proponent of the CAGW meme. Wigley, through his contentious association with Lamb apparently ‘discovered’ Bryson’s idea, and ran in a completely different direction with it than that intended by Bryson. And, voila, here we are again. Around and around this science goes.
Um, so to explain the pause those third world bad boys restored the sulfates and nitrates we had so carefully scrubbed?
Is there an equation like this:
1 volcanic eruption = X * (one person’s emission of dust, CO2, sulphur, etc)
with a robust factor X that can reliably be used in predicting and modelling the impact of future volcanic eruptions?
Reblogged this on sainsfilteknologi and commented:
New paper: man-made aerosols have had a net cooling effect since beginning of industrial revolution
This idea might have merit. The main point is that these climate theologians are not engaged in ‘settled science’ but a lot of hand-waving, metaphysics, and conjecture. The world has cooled since 1890 but blaming mankind is rather convenient for many who hate bipeds, civilization and the modern world. There is no climate – science, and a million variable convection system – there is no greenhouse – cannot be understood, let alone modelled.
I’m deeply skeptical of attempts to pin every up or down lick in climate to a cooling aerosol or a warming aerosol or merely a currently fashionable aerosol. A more serious study would be to look for a correlation between consumption of tins of baked beans with global warming due to the catastrophic warming gas methane which humans invented.
erratum – tick, not “lick”
Siberian_Husky
June 5, 2014 at 7:58 pm
says:
‘If any of the readers of this blog actually got out of their mother’s basement and travelled to China or India, they’d see for themselves the megatons of sulfur and aerosols that are pumped into the atmosphere…’
I’ve been out of my mother’s basement for 40 years. My nephew married a young Chinese woman a couple years back. Both my sisters, one of whom was his mother, traveled to China for the wedding. And, yes it is filthy. But, rest assured, not all of it’s industrial pollution. Not by any means. The cities have open sewers that run like alleys behind and between the homes and shops. Garbage is simply thrown out the rear windows. I would imagine there’s quite a bit of interesting life forms in those sewers; some of which, no doubt, moves on its own. The toilets are dry so the fumes rise up through them and are ever present in the bathrooms. And, then there’s the smoke from cooking and heating. All of this predates the industrial era. Anybody who thinks preindustrial society was “pristine” is crazy.
It gets so confusing. We are back to the future (1970s). Remember this was the reason for the “new ice age” predictions made then. So what have we learned? The warming of the Northern hemisphere is good because it keeps the ozone layer from destruction but the cooling Antarctica is bad because the ozone layer depletes. We have learned that the glaciers are going to collapse into the oceans from Antarctica because of the warming of the ocean, but at the same time the sea ice surrounding the continent is growing and breaking all modern records which of course couldn’t happen if the oceans were warming around the continent. We now learn that by cleaning up the air we are warming the planet because less sunlight is being reflected back by the soot in the air but at the same time Greenland melted in 2012 because of our soot. I could go on but I’m confused enough.
“””””…..According to the authors,
“transition from pristine to slightly polluted atmosphere yields estimated negative forcing of ~15 watts per square meter (cooling), suggesting that a substantial part of this anthropogenic forcing over the oceans occurred at the beginning of the industrial era, when the marine atmosphere experienced such transformation.” ……””””””
When I read such statements, I know I am reading gobbledegook, which is a four syllable word that means “forcing”; whatever that means.
Nobody ever measured a “forcing”, since such things don’t exist. They are the effluent left over from running computer programs, that end up with cartoons, like the Trenberth -Kiehl “global energy budget”, that measures energy, in Watts per square meter; which most scientists reserve for units of areal power density.
The real planet on which we live, actually responds instantaneously to all of the energy sources and flows, as they occur in real time. Nothing sits around and waits for something to get called a “forcing” , at which time, the CLIMATE is supposed to react to the wake up call..
But climate never happens; what happens is called WEATHER.
But in any case, under California’s current EPA / CARB regulations for crud in the atmosphere, California is less dusty today, than when the very first covered wagons, crossed the hills and valleys, and in some cases, the mountains, to settle in California. So are new clean habits are partly responsible for our reduced rainfall. Well we are a desert State anyway, so who knows what is normal rainfall, for California.
The vast majority of man made aerosols are released in the Northern Hemisphere. They don’t stay in the air very long. Therefore, only a very small % of the aerosols cross the equator.
So, the “aerosol effect” should only be present in the Northern Hemisphere and we should see a divergence from the SH on warming….the NH “cooled” by aerosols but the SH not.
But, I don’t think this has been the case. Versions of “Global dimming from aerosols” have been around for a long time. I like someone more knowledgeable to discuss the hemispheric divergence issue.
I gotta say, I’m not buying this claim about aerosol optical depth (AOD) and clouds, and for a very curious reason … the results are too good. Here’s an example, their Figure 2:
ORIGINAL CAPTION: Fig. 2. Associations between cloud properties and aerosol loading (estimated by AOD). (Top) All data. (Middle) Data filtering by the 400-hPa geopotential height using only the lower one-third subset. (Bottom) Data filtering by using the upper one-third of the 400-hPa geopotential height sub- set. First (left) column shows rain rates versus AOD. Second column, cloud top pressure (P) versus AOD. Lower P values (or colder cloud top tem- perature, third column) indicate deeper clouds. Fourth (right) column, cloud fraction versus AOD.
Where are the outliers? Where are the oddballs, the wild cards? As the clearest example, look at the rightmost graph in the middle row. Are they seriously expecting me to believe that cloud fraction in that region is a linear function of AOD and nothing else? Because that’s what that tight a relationship means, that there are no other variables messing up the picture. I’m supposed to believe that there’s never a time when the AOD is middling, say 0.1, and there are no clouds?
I’m sorry, but that doesn’t pass the laugh test.
As to how they got those results, the text says:
Mmmm … they are using 92 days of daily data. Then they “project” the data from whatever time it was measured, to 1:30 PM local time. Not sure how one “projects” cloud properties from say 5:30 pm to 1:30 pm … but let’s pretend that’s a legit operation in order to follow the story.
Then, they take the 92 days of daily data, which have been “projected” either forwards or backwards to the value they might have had at that time … or not. They are then sorted based on the AOD, and binned into a hundred bins … which implies that we are looking at more than one gridcell. Unfortunately, they haven’t provided either data or code, and they don’t discuss gridcell size, nor do they mention in their study what “n”, the number of data points, might be …
Finally, here’s the best part of their text just above, don’t know if you caught it. You really have to watch the walnut shells with these guys. Did you see where they switched the pea from one shell to the other?
Despite their paper being about cloud condensation nuclei, and their conclusions being about cloud condensation nuclei, they don’t ever measure the concentration of cloud condensation nuclei. Instead, they mention in passing that the aerosol optical depth is “serving as a proxy for CCN concentration” … say what?
The main cloud condensation nuclei for tropical rainclouds are sea salt crystals and biogenerated dimethylsulfur compounds.
Not only that, but with thunderstorms, the winds generated at the base of the clouds create spray, foam, and whitecaps. Because the upwelling air is sucked up into the thunderstorm,
However, from the point of view of the satellite, this is generally invisible, being both hidden by the clouds, and only occurring in a thin layer at the base of the atmosphere.
So no, we can’t just use the aerosol optical depth as a proxy for the cloud condensation nuclei. The oceanic CCN are lifted by upwelling air from near the surface up to the clouds. The AOD analysis won’t see that at all.
Net result? Well, if you take:
• No archiving of data as used, plus
• No archiving of code as used, plus
• No error bars on e.g. Figure 2, plus
• Unbelievably good results, plus
• Using AOD as a proxy for maritime CCN …
… well, all that adds up to is an advertisement. Don’t mistake it for science. At present, it’s not even clear what they have done to get their fantabulous results … not sure if I want to know, actually, there are some things you can’t unsee.
I suspect that at the end of the day what is happening is that when there are clouds, the AOD goes up, and not the other way around. I think there are a couple of ways this happens.
First, you might think of a thunderstorm as being an “ice volcano”. By that, I mean that their is a constant stream of microscopic ice particles being emitted at the top of the vertical pipe of the thunderstorm. Being heavier than air, they disperse and drop from the high altitude at which they were emitted. As a result, the descending air that exists between thunderstorms would have an AOD that is higher than clear air. And I note that they point out that the correlation is best around “deep tropical convection”, meaning thunderstorms …
In addition to the ice particles in the descending air between thunderstorms, down lower in the atmosphere the air is “thicker” with microscopic agglomerations of water molecules. Water doesn’t instantaneously condense at the “dew point”. As air approaches the dew point, water molecules begin to stick together. From then on, it’s a balance between the rate of growth and the rate of evaporation. As the dew point is approached, evaporation gradually slows, and the molecular assemblages of water get larger and larger. And of course, that would also affect the AOD as measured from space.
My suspicion? They’ve shown that in pristine conditions, the AOD is a function of the clouds, and not the other way around …
w.
PS—Almost forgot … they say
Man, I’m liking this data dredge even less. Seriously? They are taking half a dozen or more cloud and rain properties from MODIS and TRMM, plus the AOD.
They are then seeing how well those eight or so variables (the “cloud and rain properties” plus the AOD) correlate with no less than 286 other variables, meaning we have no less than 8 * 286 individual correlations they are mining for significance … and that’s about 2,300 trials.
They seem very impressed that in 2,300 trials they’ve found a result significant at a p-value of 0.001 … me, not so much. To be significant at the p-value 0.05 level, with 2,300 trials, you need to find a result that is significant at the p-value 0.00002.
This is global issue: Hempactivists, including me, have been watching the momentum growing to end prohibition. What is exciting to me is that hemp cultivation would provide the key to supplementing existing technologies as solar and wind. A hemp farm can produce 1000 gallons of biofuel from 1 acre. Seed oil is used as food and diesel fuel. The fiber provides 14 times more paper that same acreage for trees. The numbers are out there so why are we not growing hemp and making fuel on farm biofuel machines run with solar and biofuel. So why are people debating coal plants when we can convert existing refineries, farms and backyards to biofuel plants (no pun intended)? The jobs and opportunity Hemp promises miss the attention of media and blogs. The plant is mysterious. All Cannabis plants, sativa, Indica, hemp have no THC. They have THCA which switches to THC when aged or heated. So there is an issue whether cannabis as defined by the Controled Substances Act is illegal. So all those prisoners busted for growing weed my not be guilty unless they had THC. Oh, well just a tip of the iceberg. Can Hemp save the Planet?
From the paper that is the subject here (google translation, corrected)
Figure 5
Sunspot numbers (a) and total solar irradiance (b) the annual average global temperature correlation with the temperature distribution of lag time “lag”> 0 indicates global temperatures lagged sunspots or total solar irradiance, “lag” <0 represents the total solar irradiance sunspots or lagged global temperatures, CC is the correlation coefficient.
The graphs in question peak at 10 and 20 (presumably months).
Willis: their figure 1 shows main SSN peak at 100.9, close to your 102 years.
Figure 1
1700 to 2012 annual average sunspot number change (a) and its variance normalized global wavelet power spectrum (b) the dashed line represents 95% confidence level spectrum (white noise)
WUWT had an article recently about emissions of VOCs from trees that were discovered to be influencing cloud formation. (The terpenes etc react after release to form the active aerosols.) Nobody has ever suggested a reason for plants to produce and emit VOCs. But we do know that they are produced in prodigious amounts (a forested county emits ~100 tons per day during the warm season), and the release begins at 68F, which intensifies up to ~98F, at which time the tree goes dormant. Could trees be attempting to regulate the thermal environment? To keep temperatures cool enough for good growth and health?
Greg says:
June 6, 2014 at 8:24 pm
Since I didn’t mention 102 years anywhere in this thread, it’s not clear what this comment means. This is why I encourage people to quote the words you disagree with. You might be right, Greg, but we’ll never know until you quote or link to whatever you might be discussing.
Regards,
w.
eVince says:
June 6, 2014 at 9:32 pm
You ask,
“Could trees be attempting to regulate the thermal environment? To keep temperatures cool enough for good growth and health?”
I think you may be correct !
I remember working in a poly tunnel / greenhouse full of evergreen Escallonia shrubs. The smell of VOCs they produce always got stronger when the heat went up! Higher metabolic rate, more aromatics. If these products form aerosol by combining with gasses in the environment they are producing sites/liquid aerosols onto which water vapour can condense. I think this is an evolved mechanism to reduce water loss through evapotranspiration by ensuring it , lost vapour, can quickly condense near to the plant. Apply to a forest of trees with heat added and a rainforest forms.
Plant aromatics are produced to attract pollinators or repel predators too. Why not attract water also!
How many trees does it take to make a cloud?
http://www.interactions.org/cms/?pid=1033860
” Around half of all cloud seeds are thought to originate from nucleated particles, but the process of nucleation is poorly understood.
Sulphuric acid is thought to play a key role, but previous CLOUD experiments have shown that, on its own, sulphuric acid has a much smaller effect than had been assumed. Sulphuric acid in the atmosphere originates from sulphur dioxide, for which fossil fuels are the predominant source. The new result shows that oxidised biogenic vapours derived from alpha-pinene emitted by trees rapidly form new particles with sulphuric acid. Ions produced in the atmosphere by galactic cosmic rays are found to enhance the formation rate of these particles significantly, but only when the concentrations of sulphuric acid and oxidised organic vapours are relatively low. The CLOUD paper includes global modelling studies which show how this new process can account for the observed seasonal variations in atmospheric aerosol particles, which result from higher global tree emissions in the northern hemisphere summer.
It shows that sulphuric acid aerosols do indeed have a significant influence on the formation of clouds, but they need the help of trees.”
Does the rate of deforestation follow the temperature rise? Northern hemisphere and all that! More land area. Or do the remaining trees pump out more VOCs as the temp goes up! To cool things down!
Oceans are pretty good at producing their own sulphur containing aerosol precursor gasses, Dimethylsulfoniopropionate. Relatively low amounts, in less polluted environment open to GCR ionisation . So it is not just trees doing it. The stuff in the oceans do it,too. Contribute to the nucleation of aerosols that is.
When ‘sulphur based aerosols’ form they need an organic partner or to combine with an electrically attractive partner, either way sulphuric acid droplets need a mate to form particles stable enough to form aerosols it would seem!
I despair. Three papers published in Science in 2005 (Wielicki et al, Wild et al and Pinker et al) all showed that natural aerosol and cloud changes caused the drop in temperature globally from 1945-1975 – when clouds and aerosols caused ‘global dimming’ – NOT anthropogenic sources which can be shown to be localised (10-20% of the global surface, mostly in the northern hemisphere), whereas the dimming occurred also in ‘pristine’ oceanic areas (I reviewed this work in my book ‘Chill’, because ALL the IPCC models had assumptions based on the false premise of anthropogenic sulphur as causal factor. The ‘brightening’ began in 1980 – both in natural aerosols and reduced cloud cover, especially optically dense low-cloud – roughly 4% fall from 1980 to 2001. This brightening also occurred in rural China! despite the proximity to SO2 megacities.
Sulphur emissions are largely at 50-100m height and fall-out within a few hundred to several thousand kilometres depending on the weather conditions. The only sulphur emissions powerful enough to depress global temperature are volcanic and need to penetrate the stratosphere to stay aloft long enough to cool the globe.
The Big Bear Solar Observatory ‘earthshine’ data independently support the cloud cover changes.
WHY are these facts hardly EVER referenced????? Because they completely destroy the credibility of the IPCC ‘hindcasting’ models.