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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“UK Tmax versus Sunshine are well correlated. Cleaner Air. More Sunshine.”
http://sunshinehours.wordpress.com/2012/12/05/uk-tmax-versus-sunshine-are-well-correlated-cleaner-air-more-sunshine/
Why so much love for anthropogenic climate change? Man is puny. Climate changes all by itself (and sun).
Can I have my grant and Nobel prize please? I mentioned this in an article here two years ago. Because of pollution historic temperatures were depressed and because of the clean up we then got more sun.
http://wattsupwiththat.com/2011/05/23/little-ice-age-thermometers-%E2%80%93-history-and-reliability-2/
“Many of the cities with the longest temperature records- generally in Europe and North America- were industrialising rapidly as the thermometer came into widespread use in the 1700′s. Smog caused by the burning of coal, wood, and later gas, became increasingly widespread. Sunshine levels in the UK are said to be 40% higher now than during the worst years in London that culminated in the 1952 killer smog, which caused the various clean air acts to be enacted fully. Pollutants are said to create a cooling effect and it is easy to understand that foggy urban areas were likely to be substantially cooler than if the sun was shining. Inversions caused by these layers of air would have also helped to create temperatures that were vastly different-mostly lower-than they might otherwise have been. What effect this had on the overall temperature record over the centuries, in the many cities that smog affected to a greater or lesser degree, is impossible to calculate, but it must have been significant.
Perversely, smog became a tourist attraction and many artists flocked to great cities such as London to observe and paint the effects it caused.
Waterloo Bridge London in 1900 by Monet showing chimneys and smog. http://www.artnet.com/Magazine/features/nkarlins/karlins7-7-04.asp
An account of the historical development of smog is mentioned here;
http://en.wikipedia.org/wiki/Pollution
—– ——-
tonyb
Sounds plausible, but does the paper explain the stop in rising temps?
With the oceans, containing 99% of climate heat, any attempt to explain climate which ignores dynamics of ocean circulation is ultimately doomed. This is the “deus ex machina” atmosphere-only thinking which characterizes the AGW narrative, the belief that only human atmospheric input and nothing else can change climate, with the oceans as a passive puddle following solar/atmospheric forcing in real time. What happened to the PDO and the AMO? What about the AMOC, the bipolar seesaw and inter-hemispheric heat piracy? If we go down the road ending in believing that every fart affects the climate but the oceans are irrelevant, we will have totally lost connection with reality.
So CO2 would have warmed the earth during the 1945 and 1975 period if it wasn’t for the air pollution. So this result confirms the arguments the warmists always used to explain why there was a lack of correlation between CO2 and T for that period. So nothing new.
” leading to a staggering increase in surface solar radiation of the order of ∼20% over the last decade.”
Yes but the last decade has not been warming. Would it have cooled a lot instead? without the increased radiation?
“Mike Jonas says:
August 19, 2013 at 1:42 pm”
As well as power stations being built and grids being rolled out in the periods you mention, there was WW1, WW2, many ground/air nuclear bomb tests, several other wars which require significant industrial activity to support and would have kicked up plenty off dust.
After years following this, I’ve come to the conclusion that there is no global warming, never was (slight variations with ocean changes excepted). Its a statistical artefact caused by cooling the past in the surface temp history, a bit of unaccounted uhi, stuff like that. The reason for the ‘pause’ is that they have run out of fiddling room, pure & simple. The more I watch the sat temps bumbling around a 0.3C variance, the more I’m convinced.
So this paper is just another attempt to explain the ‘pause’ without wanting to see the elephant in the room.
Do Inda and China know all those global climate refugees are headed their way?
[ note to self: proofread before post! ]. That should be “India” above instead of “Inda”.
One thing that puzzles me is that there is a large amount on material on the internet describing ever increasing levels of pollution, for example :-
http://www.ucsf.edu/news/2013/02/13487/maternal-exposure-air-pollution-linked-low-birth-weights-worldwide
I’m not actually sure where the evidence is to show that the developing world and China have many pollution controls, I thought as the levels of pollution were controlled and reduced in the West, then the economic development in China and the Indian sub-continent etc, more than made up for it, so that worldwide they are now at levels of the late 1960’s.
If this is the case then the build up of various types of pollution may very well have moved around the world, but have not fluctuated much. Not sure where it leaves the AGW theorists and their excuse for the lack of warming since 1998. It is interesting to note that where ever there is an unexplained lack of warming then the particulate / pollution excuse is rolled out, only to be rolled back when any warming starts again, shazam ! just like something out of a Harry Potter film.
It would be a wonderful irony if it turned out that global warming was caused by environmental laws.
Probably most of the clean air acts were enacted in the developed world, so, if this idea is correct, you might expect to see more warming over the developed world e.g. Europe and the US. If I remember correctly, more global waming occurred in the northern hemisphere and it does appear to be concentrated over the developed world. It would be interesting to see if there is a significant correlation between the amount of warming and global regions which are more and less developed.
Chris
Shocker: Sea Level Could Rise 3 Feet by 2100, Climate Panel Finds
A new report from the Intergovernmental Panel on Climate Change states that the authors are now 95 percent to 100 percent confident that human activity is the primary influence on planetary warming.
http://www.nytimes.com
Link:
http://www.nytimes.com/2013/08/20/science/earth/extremely-likely-that-human-activity-is-driving-climate-change-panel-finds.html?pagewanted=all&_r=0&hp
By JUSTIN GILLIS
Published: August 19, 2013
The scientists, whose findings are reported in a draft summary of the next big United Nations climate report, largely dismiss a recent slowdown in the pace of warming, which is often cited by climate change doubters, attributing it most likely to short-term factors.
The report emphasizes that the basic facts about future climate change are more established than ever, justifying the rise in global concern. It also reiterates that the consequences of escalating emissions are likely to be profound.
“It is extremely likely that human influence on climate caused more than half of the observed increase in global average surface temperature from 1951 to 2010,” the draft report says. “There is high confidence that this has warmed the ocean, melted snow and ice, raised global mean sea level and changed some climate extremes in the second half of the 20th century.”
The draft comes from the Intergovernmental Panel on Climate Change, a body of several hundred scientists that won the Nobel Peace Prize in 2007, along with Al Gore. Its summaries, published every five or six years, are considered the definitive assessment of the risks of climate change, and they influence the actions of governments around the world. Hundreds of billions of dollars are being spent on efforts to reduce greenhouse emissions, for instance, largely on the basis of the group’s findings.
The coming report will be the fifth major assessment from the group, created in 1988. Each report has found greater certainty that the planet is warming and greater likelihood that humans are the primary cause.
The 2007 report found “unequivocal” evidence of warming, but hedged a little on responsibility, saying the chances were at least 90 percent that human activities were the cause. The language in the new draft is stronger, saying the odds are at least 95 percent that humans are the principal cause.
More at Link:
http://www.nytimes.com/2013/08/20/science/earth/extremely-likely-that-human-activity-is-driving-climate-change-panel-finds.html?pagewanted=all&_r=0&hp
James B
Chicago
@tonybclimatereason
April to August 1952 on CET are very much on the warm side, do you have figures for London during that smog?
Extra irony here when you think about how the CAGW folks have sold the scare to the general public. Most non-scientists are screaming about “carbon pollution” causing the world to heat up. They think “pollution” is causing warming. They get furious with you if you argue against the climate alarmist agenda because they are certain you are against stopping “pollution.” So you must either work for the oil industry, be an idiot or hate the planet.
Perhaps a great moment for us to push back if we could get folks to understand that what they think of as pollution, sooty emissions, cools the planet.
Ulric
Here is London weather. seems to be on the cool side in 1952. The smog was very ,localised and Greenwich due to its height/location may have missed it.
http://www.london-weather.eu/category.46.html
Annoyingly, the official figures for Greenwich are missing for a couple of years including 1952
http://climatereason.com/LittleIceAgeThermometers/Europe.html
tonyb
Ulric
Interesting letter here from the weather keeper at Kew close to Greenwich in 1952
http://onlinelibrary.wiley.com/doi/10.1256/wea.09.03/pdf
tonyb
James B:
You have copied your daft post at August 20, 2013 at 4:06 am on another thread.
I refuted it there and this link goes to my refutation.
http://wattsupwiththat.com/2013/08/19/ipcc-caught-with-an-old-uncorrected-error-in-new-ar5-report/#comment-1395290
Richard
“tonyb says:
August 20, 2013 at 6:33 am”
The smog in London was a photographers delight back then. Soft, diffused light.
Also explains why Northern and Southern hemispheres behaved differently.
Re: New York Times article By JUSTIN GILLIS
Published: August 19, 2013
Notice the slight of hand change from “increasing” climate extremes to “changing” climate extremes. So now any climate extreme change, IE up, down, more, less, here, there, is likely at least greater than 50% prompted to occur because of human factors.
So now we have the bottom line. Humans cause bad weather. We have made a complete turn around back to caveman days when lightening was a sign from the gods that we have done something wrong. Quick! Find a virgin!
What a crack of horse sh*t.
First off I suspect that the is ** NO ** direct linear relationship between electromagnetic radiation hitting a small particle of “something” or pollution and the amount of radiation is back scattered.
Anybody care to share an “energy balance” equation of an airborne particle being struck by radiation – from the sun?
We go from -24 to +10 and now back to -3.
Is the recent 15 year flatline due to China and India? If so please stop it as I like a warmer, greener world. I don’t mind them putting CO2 into the air as long as they stop polluting while doing it 🙂
What about the 1930’s Dust Bowl? (1932-36) When dust from the Midwest was blown all the way to Washington DC?
1. We know the 1930’s were hotter than now.
2. In 1930 13% had electricity in rural America. by 1940 33% had electricity. (Farmers made up 21% of labor force)
3. This graph shows the use of coal (by percentage) peaking in the 1920/30’s