Pollution controls have contributed to a more transparent atmosphere, thus allowing for “…a staggering increase in surface solar radiation of the order of ∼20% over the last decade.”
A new paper (O’Dowd et al.) from the National University of Ireland presented this summer at the 19th International Conference on Nucleation and Atmospheric Aerosols suggests that clean air laws put in place in the 1970’s and 80’s have resulted in an increase in sunlight impacting the surface of the Earth, and thus have increased surface temperatures as a result. In one fell swoop, this can explain why surface temperature dipped in the 1970’s, prompting fears of an ice age, followed by concerns of global warming as the air got cleaner after pollution laws and controls were put in place.
WUWT covered a similar effort (Wild 2009) here and paper here (PDF 1.4 mb) which showed the issue but fell short of showing a provable causation for temperature.
Now with this new effort by O’Dowd et al., it seems quite likely that cleaner air is in fact allowing in more solar radiation to the surface, and thus increasing surface temperatures by that increase of insolation.
Wild 2012, was a follow up, and figure 1 above is from that paper.
Martin Wild, 2012, Institute for Atmospheric and Climate Science, Zurich, Switzerland. Published in BAMS: Enlightening Global Dimming and Brightening
http://journals.ametsoc.org/doi/pdf/10.1175/BAMS-D-11-00074.1 (open PDF)
Now with O’Dowd et al. and their findings, this “global brightening” as a climate driver is looking much more plausible.
The authors write in the new O’Dowd paper:
This study has demonstrated for the first time, using in-situ PM measurements, that reducing aerosol pollution is driving the Insolation Brightening phenomenon and that the trends in aerosol pollution, particularly for sulphate aerosol, is directly linked to anthropogenic emissions. Ultimately, the analysis demonstrates that clean air policies in developed regions such as Europe are driving brightening of the atmosphere and increasing the amount of global radiation reaching the Earth’s surface. The actual impact of cleaner air and insolation brightening on temperature remains to be elucidated.
And offer this graph:
This is inline with Hatzianastassiou et al., 2012, Features and causes of recent surface solar radiation dimming and brightening patterns:
Surface incident solar radiation has been widely observed since the late 1950s. Such observations have suggested a widespread decrease between the 1950s and 1980s (“global dimming”) and a reverse brightening afterward.
http://adsabs.harvard.edu/abs/2012EGUGA..1413344H
The new O’Dowd paper:
Cleaner air: Brightening the pollution perspective?
AIP Conf. Proc. 1527, pp. 579-582; doi:http://dx.doi.org/10.1063/1.4803337 (4 pages)
Abstract:
Clean-air policies in developing countries have resulted in reduced levels of anthropogenic atmospheric aerosol pollution. Reductions in aerosol pollution is thought to result in a reduction in haze and cloud layers, leading to an increase in the amount of solar radiation reaching the surface, and ultimately, an increase in surface temperatures. There have been many studies illustrating coherent relationships between surface solar radiation and temperature however, a direct link between aerosol emissions, concentrations, and surface radiation has not been demonstrated to date. Here, we illustrate a coherence between the trends of reducing anthropogenic aerosol emissions and concentrations, at the interface between the North-East Atlantic and western-Europe, leading to a staggering increase in surface solar radiation of the order of ∼20% over the last decade.
h/t to Sunshine Hours
It seems like a possible case of Occam’s Razor in action – the simplest explanation is the most likely.
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If i get this right, industrial pollution masked the natural warming from the Little Ice Age and the clean air initiatives caused the earth temperatures to rebound to normal levels.
REPLY: Bingo. – Anthony
Do ya think this will turn Al Gore, Michael Mann, and Jim Hansen into advocates of burning coal with high sulpher content? It would sure help Appalachia if they did, and kill the effects of bad ole CO2 in just one blow.
Ok, so the world is happily warming out of the LIA at a fairly brisk but not worrying rate, then we get all industrial and start shutting out the sun. This is so effective that people start talking about a coming ice age.
Then we decide to clean up our act, and over the next couple of decades we get the gentle warming we would have anyway plus catch up on the bit we’d supressed, eading to all sorts of apocalyptic alarm bells. About 15 or 16 years ago the planet caught up and things have levelled out since.
Makes logical sense to me!
That natural warming trend seen in the temp records as recovery from the LIA is so often dis-regarded. How many times do warmist types crow over record high temps. Or a record in record high temps. Record high temps would be expected with even with ZERO CO2 effects, through the oft forgotten natural warming trend we have enjoyed since the LIA.
Sorry – too late. The science is settled. This window is closed.
I remember the “pea soupers”, very opaque smog (smoke plus fog) when even the ground at your feet was difficult to see. That was in the sixties, but apparently it was worse before then. I have not witnessed anything like that in recent decades.
I find this more believable than AGW due to GHG.
Seems to make a lot of sense, so the Global Warming Industry will do their very best to ensure this theory is stillborn.
C’mon trolls, do your best..
Joe makes a good point. In the seventies, climate scientists (including some of the same culprits), were warning of an imminent ice age. Then it started warming. It does fit.
Base on this theory Washington D.C. should be friggin freezing with all the crap being thrown into the air there.
I remember this scenario being discussed years ago here at WUWT. Not sure how much I buy it. 20% is a whole lot.
Today it’s hazy in Santa Rosa and the nearby mountains to the East are bluish and low-resolution, unlike their usual crisp definition. The light on my garden is diffuse and the temperature is about 10 F lower than yesterday. I began monitoring fine particle (PM2.5) levels in my back yard last week and after 5 or 6 consecutive days in the 1-5 ug/m3 region, today it is more like 50. So one can well believe in the effect of aerosols in reducing solar radiation.
Prevailing theory is that atmospheric nucleation is a ternary reaction process involving sulfuric acid (resulting from the sulfur dioxide produced in this country by the great power plants of the Midwest), ammonia (from feedlots, for example) and water vapor. While living in Virginia, I monitored ultrafine particles and could see the process begin between 10 AM and noon, reaching very high concentrations approaching 100,000 per cc, and then declining in the afternoon. These “nucleation bursts” covered enormous areas (thousands of square kilometers) and happened fairly often, several times a week in summer, somewhat less often in winter.
Moving to Santa Rosa last year, I did not expect to see them happening here, since the West doesn’t have much sulfuric acid in the atmosphere. However, I began monitoring UFP here last week and saw an increase up to 40,000/cc on one or two days last week. Maybe the nitric acid here can also participate in the nucleation process.
Unfortunately, ultrafine particles are not on the EPA’s radar, despite the evidence that they can produce severe oxidative stress and perhaps even broach the blood-brain barrier by using the olfactory channel, so very little monitoring of atmospheric levels is occurring, thus making it impossible to do epi studies linking concentrations with health effects. One such study occurred in Erfurt, formerly East Germany, where UFP monitoring occurred over several years and was sufficient to show that mortality from cardiorespiratory disease was significantly linked to UFP and NOT to fine particles (which is what is regulated in the US and Europe).
One wonders whether the increase in sulfur dioxide that will occur in Germany and China and India due to coal will be sufficient to roll back the general decrease that occurred in the 43 years since EPA was created. Perhaps not if good scrubbing techniques are employed.
Count me out. This smells just like the claims that the ~1940-70 cooling was caused by (man-made, unmeasured) aerosols. This hypothesis only runs marginally OK from ~1940 onwards. It has no explanation for the ~1910-40 warming, or for the cooling before that. To me, it’s a non-starter.
If that is so, could the increasing aerosol pollution being produced by China be part of the reason for the “global warming” standstill occurring for the past decade or more?
Hahahahahahahaha. Blame Nixon.
Jonas, look up “Little Ice Age”. You’ll better understand why it was warming in 1900.
I bet the BBC fails to mention this.
Could the pause be the result of polution from China and India?
The warmists will probably say this even more reason to stop burning fossil fules.
Is this a peer review paper….? I could not tell from the link.
REPLY: yes, it is in the American Institute of Physics (AIP) website – Anthony
I am an unashamed Denier, but I have noticed two, somewhat contradictory streams in papers which are in disagreement with CAGW. Many are like this one, explaining the temperature increase in terms of something besides CO2 levels. In fact, there are multiple explanations which have appeared here. The other stream argues that there is little or no GW when questionable “adjustments” are taken out, proxies are fixed, etc. Bad physics and bad ideology are not mutually exclusive. Warmist theory predicts anything, but it seems we are suffering from an excess of explanations which predict the same thing.
Count me out as well. Weather pattern variations can also account for the increase and decrease in aerosols. By FAR the most prevalent is soil and plant dust which has a pattern variation tied to periods of drought caused by weather pattern variation, the next is salty sea spray which is tied to winds, again caused by weather pattern variation. And then there are clouds driven away or allowed to stay depending on equatorial winds and humidity, again caused by weather pattern variation. Of the aerosols ascribed to human cause, the percent change of just those particles would not be capable of driving the temp trends. They are riding on the coattails of the big leagues.
So John Tyndall was wrong, just like Darwin!
Tom G(ologist) says:
August 19, 2013 at 1:17 pm
“Sorry – too late. The science is settled. This window is closed.”
Just like Piltdown Man was finally recognized as a hoax, so will some day very soon the entire climate science since 1971 be discarded. And all the youngsters now studying climate science to become do nothing rent seekers will have to find a way to earn their bread.
Is this a peer review paper….? I could not tell from the link.
REPLY: yes, it is in the American Institute of Physics (AIP) website – Anthony
——–
Thanks!!….I used the wrong link
I mentioned this in a post here in the past year. Nice to see the obvious getting traction. It also proves the adage “No good deed goes unpunished”. “Be careful of what you wish for” comes to mind, too. My motivation was the realization that some of the Arctic warming (pools and similar effects of insolation) can be explained by cleaner air. Even with low slant angles, the effect of sunlight will be greater through cleaner air. Deductive reasoning, at best, certainly.
Schrodinger’s Cat says at August 19, 2013 at 1:48 pm
That has no significance.
They fail to report lots of things.
The number of unreal things the BBC fails to report is not greater than the number of real things.