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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I remember the sky being a brownish-blue and wondered what it was that the old books talked about a vibrant blue sky. The Crayola “sky blue” crayon didn’t make sense to me as it didn’t have a brown tinge, Then the family went on vacation and drove through the mountains in Montana and I understood. The sky really was blue. By the time I graduated high school, the sky was pretty much that way everywhere. Then I joined the USAF and got assigned to Korea, and it was back to the brown sky again, especially in the winter with all the charcoal heating they used. I remember flying out and about 200 miles off shore, the color of the sky and sea went from a yellow-brown to a vibrant blue. Pollution can indeed be a problem.
I remember the smogs well and the paper being discussed seems quite credible to me in view of my personal experience of these events.. Smoke was probably a major factor at that time in the industrialised parts of the UK and probably elsewhere.
I just wish to make the point that I am not in a position to draw conclusions about the current lack of warming and the possible connection with pollution in China. I just do not have the data or personal observation on which to form an opinion either way.
Interesting.
Two articles for background reading (link follows quote):
# ONE:
“The towns of Donora and Webster, Pennsylvania, along the Monongahela River southwest of Pittsburgh, were the site of a lethal air pollution disaster in late October 1948 . . .”
http://www.pollutionissues.com/Co-Ea/Donora-Pennsylvania.html#b
# TWO:
“The light-colored form of the moth, known as typica, was the predominant form in England prior to the beginning of the industrial revolution.”
http://www.millerandlevine.com/km/evol/Moths/moths.html
Dave L 2:08 says
So, in other words, the EPA is responsible for global warming.
laughing out loud
Eugene WR Gallun
“what would explain the decline between ~1878-~1910”
UK coal production went from 72 million tonnes in 1853/62 and peaked in 1903/12 at 258 million tonnes. and then down to 208 million tonnes by 1943/52.
https://www.gov.uk/government/statistical-data-sets/historical-coal-data-coal-production-availability-and-consumption-1853-to-2011
Friends:
A decade and more ago in posts on several blogs I wrote the following prediction.
The global climate cooled for ~30 years from ~1940 to about ~1970.
Alarmists then claimed the global cooling was caused by emissions of SO2 from power stations.
The global climate warmed for ~30 years from ~1970 to about ~2000.
By ~1980 the global cooling scare became untenable so the global cooling scare was morphed into the global warming scare.
Alarmists then claimed the global warming was caused by emissions of CO2 from power stations.
If the global climate cools for more than ~10 years then the global warming scare will probably be morphed back into a global cooling scare.
This prediction was ridiculed by warmunists whenever and wherever I made it.
Global warming has stalled for more than 16 years.
The subject of the paper reported in the above post is a suggestion that SO2 from power stations has caused global warming to stall.
I see no reason to change my prediction which I repeatedly made a decade and more ago.
Richard
It’s probably already been said, but I think solar and ocean cycles have far more to do with it than just clean air, as the MWP to the LIA will attest. It’s an idea, but that study on such a short time frame with many other factors not taken into account shouldn’t be taken too seriously.
As we know from many sources such as Vostok ice core data, since the end of the last deep ice age some 10kya, the planet’s been cooling gradually and can’t be due to just the air getting a bit dirtier.
REPLY: yes, it is in the American Institute of Physics (AIP) website – Anthony
—–
It can only be a matter of time before the SKS boyz are in full rebuttal mode against this paper.
I predict a flurry of Guardian articles under the 97% banner – How long before resignations follow at the AIP?
Global warming is the fault of the unwashed masses of mankind….
The science is settled.
Owen in GA says:
August 19, 2013 at 2:47 pm
Remember when the sky was brown?
Ha, go to Denver and look down from Look Out Mountain, or out west by Leydon Junction/Rocky Flats or from Broomfield.
There exist a brown haze.
This theory is far more convincing than the CAGW due to CO2 and other ‘greenhouse’ gases. However, first, I would like to check some temperature records that have not been surgically renovated to support the CAGW cause..
It’s just one more piece of the puzzle. It’s now the job of good climate scientists to put them together to show the whole picture. These silly warmists have a few pieces of the puzzle and have jammed them into some distorted version of the truth that suits them. They have a few pieces and refuse to look at the whole picture. Hopefully the capstone will be identified before too long.
Talk about unintended consequences!
Well the general idea sounds plausible, including the possibility that Chinese (and apparently Indian) ramp up industrially, could be a cause of the present static condition.
I’m bothered by the 20% number.
A TSI number of 1362-6 (which used to be 1353) used to give a nominal 1,000 W/m^2 at the earth surface; this a result of blue sky scattering, plus atmospheric absorption; O3, H2O and CO2, plus “aerosols.”; which is about a 25% reduction.
A 20% increase would take us back to around 1,200 W/m^2 at the surface, and I haven’t heard of any solar energy companies using a value like that recently.
But in California, which historically has had real smog conditions, we supposedly have cleaned up our air (on average) so it is now cleaner than when the first covered wagons rolled across the borders. Now nobody in LA would believe that; but they are in LA, which should tell us something about them.
I’m not in the Occam’s razor fan club. Einstein, also told us that scientific theories should be as simple as possible; BUT no simpler !
A full analysis of all that is going on climate wise; well at least Temperature wise, is still a very complicated set of interractions; so I wouldn’t describe it as a simple problem, or solution.
But I can generally be persuaded, that processes which ALTER THE GROUND LEVEL SOLAR INSOLATION, are considerably more likely to explain climatic Temperature changes, than any GHG diddling with outgoing LWIR radiation. Yes that would include cloud feedback.
Yes I do accept that GHGs interfere with LWIR escape. I just don’t see any plausible mechanism, for that to return significant “heat” energy to the surface.
If this were the case, wouldn’t we expect cooling (or at least much less warming) in those regions of the world where aerosol depth has continued to increase (e.g. India or China)?
Seems not to be the case in practice:
http://berkeleyearth.lbl.gov/regions/india
http://berkeleyearth.lbl.gov/regions/china
Also, its worth pointing out that GCMs have long incorporated both direct and indirect aerosol forcing, so I’m not really sure how new this is…
Mike Jonas said:
“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.”
The rolling out of electric might fit with the pre-1940s warming. Cleaner fuels and more centralised energy generation leading to less pollution perhaps.
An increase in solar radiation reaching the surface did occur over 1980s-2000 as implied, especially with fewer shading clouds than during the global cooling scare period before it. However, given how much there is a match of five peaks and five troughs in sea level rise rates, humidity, cloud cover, and temperature with forcing from cosmic ray flux over the 1960s-2000s period of neutron monitor data as illustrated in http://s24.postimg.org/rbbws9o85/overview.gif (with reference links given: enlarging on further click), variation in human aerosol emissions would be supplemental to that, not the only factor. While I haven’t cross-checked the Wild global dimming/brightening article’s figures, likely it is basically right in what it says, just not including the bigger picture, making it the truth but not the whole truth.
What about the Southern Hemisphere which is mostly ocean? I’m under the impression that the pollution from the NH has a hard time migrating across the equator.
Mace Head from 2001-2011. ………… at Mace Head, 2003-2011
But global temps went down from 2001-2011
I also see an obvious error in the balance cartoons. If the LW up goes from +1 up to +2, the LW down, should only go from +2, up to +2.5, not to +3, because the re-emission from the atmosphere has to be isotropic, so only half of it can come down, the rest goes up.
I’m not a particular fan of that diagram representation anyway.
Empirically speaking, I remember discussing with my wife, way back in the early 80’s, how we both felt the sun seemed warmer on the skin than it had used to. So I’m not surprised by this paper.
The surface currently receives 243 watts/sqM on average. 20% increase would amount to an extra 48 watts/sqM. Just based on the stefan boltzman law that would equate to about 12C rise, significantly more if one takes into account cloud and ghg effects. If true it would imply negative feedback strong enough to reduces 12C to about 0.5C (assuming all the “adjustments” are justified). Even accepting that negative feedback is highly likely, that’s pretty strong negative feedback.
Now where has this extra energy come from. Is it energy which was previously reflected back out to space. If so the change implies a change in albedo from 0.3 to about 0.15. Since we monitor albedo from space I find it exceptionally implausible that such a huge change would not have been observed.
Is it energy previously absorbed by the atmosphere. If so it is still energy injected into the biosphere so overall it may not have all that much effect. However reducing the energy injected directly into the atmosphere by a massive 48 watts/sqM (and it is truly massive) should have had very noticeable effects such as cooling of the atmosphere, a change in the apparent lapse rate or substantial change in height of the tropopause etc. None of these seem to have been reported.
To put it in perspective, the generally agreed direct impact of doubling CO2 is about 3 watts/sqM so this is something like 16 times larger. If doubling CO2 could have any noticeable effect this should be a standout red flag no one could miss, even with crude instruments.
The concept in principle seems quite plausible but the magnitude claimed seems grossly implausible. But then isn’t that the issue with essentially all of climate science today. After all the whole issue with CAGW is not whether its wrong in principle but rather whether the effect is 3C or 0.3C
This is something that I have tried to bring attention to in Australia. The Gillard Labor government came into power on the leader declaring there would be “no carbon tax in the government I lead” but promptly went into a convenient alliance with the greens and independents to form a government. C02 became the devil, the looming disaster, therefore a carbon tax HAD to be imposed to stop “Dirty Carbon Polluters” and save the planet. The green mantra meant that they must point out we were very large polluters when measured on a per head of capita basis in world emissions of C02. Our industry was to be crippled on the alter of demonizing C02 with emotional claims and unproven theories.
I tried to point out that the “Black carbon pollution” that Prime minister Gillard liked to claim when referring to C02, had in fact been removed along with other atmospheric pollutants for 30 years or more by way of very stringent EPA regulations and the installation of expensive emission scrubbers in all smokestacks, and intensive monitoring of other forms of pollution. Australian Industry and the Australian public had paid the cost, had paid the higher prices of the resulting domestic goods, and here we were being asked, to pay crippling additional costs because we had a small relative population when compared with other developed nations, when it was our leader trying to justify a huge carbon tax that would cripple our industry, reduce jobs as we paid guilt money to the green movement and what a lovely tax liked to ever rising C02, a tax meisters dream.
Of course they claimed the moral high ground as the reason for the carbon tax, why else? You have to wonder, as the green movement was insisting we must also close down our coal fired electricity generators, that had supplied us with some of the cheapest electricity power, we also could not build any dams to increase Hydro power output though we had several flood prone rivers suitable. My take was that we had cleaned up the atmosphere so much perhaps we had allowed more sunshine through?
The same government after imposing a carbon tax was encouraging the sale of our 500 year reserve of best quality coal, in an enhanced export program expected to cut that use time in half by exporting the coal to be burnt in countries like China and India, to fuel their power stations and feed their industry. These countries, unlike Australia haven’t been burdened with the need to scrub emissions of any kind from their smokestacks or clean up their own wasted environments.
Tasmania the Australian island state was once the “apple isle” of Australia, with large Forestry industries, and blessed with abundant Hydro power that supplied the cheapest electricity in Australia. Tasmania has been a hotbed of green activists, Taken over by green zealots who decimated the Forestry industries, reduced employment prospects. It now has the most expensive electricity in Australia, high unemployment, high welfare dependency and some of the highest food, fuel and commodity prices for domestic consumption.
America should send their economic experts to study how green activists can so cripple a state economy and reduce it to basket case status, before heading down that Green poverty path.
Peter Miller says:
August 19, 2013 at 1:23 pm
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..
No need for trolls. The best response from the Global Warming Industry comes from Martin Wild himself in the papers cited repeatedly by Anthony Watts. Wild is clearly in the AGW/GHG camp. He says global brightening is merely a temporary phenomena that “masks” the enhanced GHG effect. From the 2012 paper cited by Anthony:
“Thus, with the foreseeable inevitability
and undisputable necessity for clean air regulations
and aerosol reductions also in emerging nations,
potential dampening of global warming by a renewed
dimming could only be temporary, and greenhouse
gases will ultimately become the sole major anthropogenic
forcing factor of climate change.” (Wild 2012)
He also launches a defense of the IPCC climate models, noting that they are accurate with respect to the southern hemisphere, where there has been far less “brightening” than the northern hemisphere:
This suggests that climate models simulate decadal warming
trends adequately when greenhouse gases act as the
sole major anthropogenic forcing as in the SH, but
may have difficulties when in addition strong decadal
aerosol variations come into play, as in the NH.
The BBC Horizon (think PPS NOVA) did a whole one hour show on global dimming back in 2005. Of course back then to explain the cooling 1950-1980. Surprised more people did not comment on it here.
http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_prog_summary.shtml
Either way we sure should not be worrying about cutting CO2 as it is most likely a very small factor in warming which will not be a big deal at all. Any changes, most likely to be small, we will adapted to and not even notice.