From the “Department of Unintended Consequences” and Georgia State University comes this oops moment in science. And all that time we are being told by people like Peter Stott that it was the increase in “global warming” that has increased rainfall.
Georgia State University research finds Clean Air Act increased Atlanta rainfall
A Georgia State University researcher is the first to show that the Clean Air Act of 1970 caused a rebound in rainfall for a U.S. city.
Jeremy Diem, an associate professor in the Department of Geosciences, analyzed summer rainfall data from nine weather stations in the Atlanta metropolitan area from 1948 to 2009. He discovered that precipitation increased markedly in the late 1970s as pollution decreased following passage of the Clean Air Act of 1970.
Diem also noted that pollution in the 1950s and 1960s caused rainfall to drop in the Atlanta area.
Previous studies have found a general link between air pollution and rainfall, with higher concentrations of particulates in the air suppressing rainfall.
Diem’s research shows, for the first time, that a substantial decrease in pollution in a specific metropolitan area caused an increase in rainfall, Diem said, noting the findings are likely to apply to other urban areas across the United States that saw similar pollution decreases.
“Really, the only plausible reason for this increased rainfall is the reduced pollution due to the passage of the Clean Air Act,” Diem said. “This probably happened in many cities other than Atlanta.”
The study may also have implications for other urban areas around the world that may be experiencing drop-offs in rainfall due to pollution, Diem said.
To view Diem’s study, published in the journal Atmospheric Environment, visit: http://www.sciencedirect.com/science/article/pii/S1352231013002951.
http://www.earthzine.org/2008/07/02/the-drought-of-2007-a-foreshadowing-of-things-to-come/
http://www.wsbtv.com/news/news/drought-not-over-lake-lanier-lower-than-this-time-/nJXbf/
http://www.ajc.com/news/news/lake-lanier-water-level-sinks-to-three-year-low/nTGCd/
some moron at Ga State doesn’t know Lake Lanier is in N. Georgia
I am going to throw what little weight I have to those who argue that correlation is not causation.
My own take on pollution dates to my time in the eastern Cleveland suburbs in 1969-1974, right in the heart of the pollution just around the time of the Clean Air Act, but before the effects could really take effect. In fact, I started my working career in engineering on air pollution control equipment, all of which was contracted for because of the dictates of the Clean Air Act.
The eastern suburbs of Cleveland have another name: The Snow Belt. But it wasn’t just snow. It was also rain. It was the rainiest place I’ve been in. I recall several times on my Army missile base in 1969-1970 such sustained rains that we referred to them as monsoons – conditions rare in the U.S. Midwest. It also happened to be directly downwind of the steel mills and a lot of other heavy industry in the Flats of the Cuyahoga River (yes, the one that “caught on fire”) and all over the city.
The prevailing westerly winds came across Lake Erie before passing over Cleveland. The shore runs very much SW to NE. As I had it explained to me back then – and it made a lot of sense – the air picked up moisture over the lake and then the pollution gave the water vapor particles to condense upon, at which time it was very likely to fall as precipitation, winter or summer.
The reason this made and continues to make sense so much is that the Snow Belt was only east of Cleveland, not east of other areas along the Lake Erie shore. (I also experienced several snowfalls beyond anything I’ve gone through elsewhere in the Midwest. In one 12″ of snow fell in slightly less than an hour.) It also makes sense in the light of recent articles about (as I recall off the top of my head) nucleation and particles contributing to water vapor condensation.
This paper seems to fly in the face of all of this. It appears to me to be exactly 180° wrong.
Steve Garcia
Philip: Are you sure that the lack of rain in your studies, around urban areas is not as a result of the UHI? That is, warmer air rises and raises the dewpoint, thereby preventing precipitation that cooler air would otherwise allow?
Maybe someone from Oz BOM could comment on Sydney. Newcastle & Wollongong historical rainfall? A generally high summer rainfall, prevailing moisture laden – from the Pacific – N.E. winds, reduced air pollution and steel making industries shut down. Anyone with BOM contacts? Cheers from cool Sydney.
Mario, UHI is substantially a reduced evapotranspiration effect. Urban air is warmer because it is less humid. Humid air is less dense than lower humidity air and thus rises, causing convection. Therefore it’s not clear there is enhanced convection over urban areas. No studies finding this came up in a quick search.
And how to explain the increased the increased precipitation downwind?
Urban air is warmer because of heat released from surfaces that warm during the day and from energy use in concentrated areas. Warmer air can hold more water, and therefore reduce humidity. Warmer air rises too. All of these effects can cause circulation patters and of course affect rain amounts around urban areas. I’m just pointing out that these statements are true and separation of these truths is difficult. That is all.
The magical thinking in this study is apparent: “Look – passing legislation changes the climate!” and makes me doubt it much more than if the author had simply provided data on particulate levels and rainfall. As someone above noted, even if particulates have a strong effect, it may be that the closure of old industrial plants, changes in land use and a host of other factors need to be taken into account.
I am surprised that he didn’t use the LA basin as the poster child for this study. There must be plenty of data out there about particulates and rainfall, and there have been dramatic changes in the former in the last 40 years or so.
Philip Bradley says:
June 5, 2013 at 12:15 pm
This has been obvious from multiple lines of evidence; the Weekend Effect, increased SSTs downwind of the US east coast cities, etc.
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BTW, the late 20th century warming began in 1976, the same year vehicle catalytic converters were mandated in N America.
Philip, perhaps the other studies have more useful data than this one does? This study proves nothing at all which I will explain. Catalytic converters are probably not the cause of the warming either. Warming started prior to that, and even than people probably did not switch over because at first those regulations only cover newer vehicles. This is not to say that this theory is not true, but this study certainly does not prove a darn thing in general in this department. Personally, I would just sit, measure and wait 30 more years to see if the weather patterns change because I am willing to bet that most of the change was probably natural.
“Really, the only plausible reason for this increased rainfall is the reduced pollution due to the passage of the Clean Air Act,” Diem said. “This probably happened in many cities other than Atlanta.”
WOW….the scientific method tells us that the null hypothesis is that all changes in precipitation are due to natural causes. And you did not find that plausible? You did a statistical test and think a statistical test DISPROVES anything? Wow again!
Basically, their argument boils down to the fact that rainfall is not supposed to ever change more than it has in the 30 years of their test sample. (approx from 1945-1975) Their “base-line” which is weak as heck is a 30 year time period and they claim that the climate of any area is never going to change more than it does in 30 years. Quite a preposterous claim logically.
Especially since they have no control in their study like “other cities” which shows similar levels of change. And to top this off, their data for pollution levels is NOT EVEN in Atlanta. This is similar to a study I saw about fish in California going extinct about a week ago. They came to conclusions without even checking California river temperatures and instead used a study that covered the entire US. How do you know pollution levels decreased in Atlanta at the same rate as the rest of the US? What if the pollution in Atlanta actually went up and your conclusions are directly opposite of reality? How do you know that California rivers did not actually cool and will continue to cool?
If you do not even know the answer to those key questions, you can stop, and hang your head in shame over releasing your name on this study combined with a very pointed conclusion.
They do not control other variables at all (as this is impossible with such little data). They can not rule out other causes (including natural causes.) and to top all of that off, they find it implausible that anything ELSE could have caused this? What if CO2 rise by itself is causing this with increased warmth? Is that not plausible with “97% of scientists” agreeing that global warming is happening and that “Warmer air holds more moisture”. Perhaps prior to the 1980’s CO2 was not high enough and we were too cold for the rainfall to increase.
I bet there are about 40 other things I could “find just as possible” as pollution as the cause of change if I used just US data. Does not mean that any of those things is anymore likely though.
And that is the entire point, There are tons of other explanations including the null hypothesis and these “scientists” claim that there is nothing more plausible than their own pet theory. Rubbish as usual.
Urban air is warmer because of heat released from surfaces that warm during the day
I know a lot of people believe this, but for it to be true, urban albedos must be lower than the albedo of surrounding rural areas and this is not the case for most cities. The exceptions are older cities, Munich and Tokyo in the paper below. The reason is modern cities use more high albedo materials, particularly concrete. The albedo of concrete ranges from 0.3 to over 0.5. Whereas, the albedo of a forest is about 0.1.
The main source of additional heat (as opposed to increased temperatures) is the Urban Canyon Effect. But this is complicated by additional boundary layer mixing from taller buildings.
The paper says that while waste heat can heat urban centers by as much as 3C, the effect is negligible in suburban areas.
http://www.javeriana.edu.co/arquidis/educacion_continua/documents/Urbanclimates.pdf
Philip you wrote: The paper says that while waste heat can heat urban centers by as much as 3C, the effect is negligible in suburban areas.
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I believe I said this as one of the reasons urban areas are warmer. I’m not sure what you are arguing about. Forests might have a lower albedo, but they also use energy in growth, and they sweat water, which cools them. You are trying to oversimplify subjects with single parameter arguments.
“I’m not sure what you are arguing about.” [Mario Lento to P. Bradley]
So, PB is at it again over HERE (just ran into his inanity on the latest Bob Tisdale thread — head shake). He obviously just argues for the sake of it. Only a warped mind engages in perversity for perversity’s sake.
Whatever Mario says either: 1) say the opposite; or 2) mischaracterize what he said and argue against that. It is, apparently, called “The PB Principle.”
Yeah, PB, this is an ad hominem post because YOU are the problem.
Yes Janice… It’s not possible to have a cogent exchange with some people…
Philip, do you believe in CAGW? This is a yes or no question. But feel free to elaborate.
So, PB is at it again over HERE (just ran into his inanity on the latest Bob Tisdale thread — head shake). He obviously just argues for the sake of it. Only a warped mind engages in perversity for perversity’s sake.
It’s the scientific method.
Philip, do you believe in CAGW? This is a yes or no question. But feel free to elaborate.
No. I think AGWism is mostly misinterpretation of a limited dataset, combined with the selling of climate models as scientific predictions, which they aren’t. And sold to a scientifically naive audience.
If you read WUWT on a regular basis, you will see that the motivation of many posters here is drag climate science back towards science.
Reduced pollution may have caused both the rain and the warming. After all, CO2 can’t “match” the mid-century cooling or the rapid increase in temperature of the 80s or 90s without anthropogenic aerosol forcing as well. However the increase in precipitation associated with the warming is not just urban but global (per Wentz 2007) and both the increase and the failure of the models to represent even half of this negative feedback from acceleration of the hydrological cycle were more recently confirmed by a salinity/freshening study.
http://www.sciencemag.org/content/336/6080/455.abstract
To Philip Bradley and others:
My comment at 1:27 PM yesterday was agnostic about whether and how urban pollution may increase or decrease rain downwind of a city. The article says that decreasing pollution increased rain downwind.
My point was that the study did not actually do what the conclusions said it did. The conclusions said that reduction of PM10 in Atlanta, caused by the Clean Air Act, was correlated with increase in rainfall downwind.
But the PM10 data was national, not local. Strike one.
The reasons for reduction in PM10, nationally, in the 1970s included major issues that had little to do with the Clean Air Act — mainly the closure of so much of our older factories during the severe recession of 1974/5, caused by the first oil embargo. Atlanta didn’t have any of these massive old, highly polluting factories. So I would have expected that pollution reduction in Atlanta would have taken a substantially different pattern than the national data. Strike two.
The author attributes the increase in rainfall to reduction in PM10 (which wasn’t regulated per se by the EPA until 1987). But EPA also regulates, now, a smaller type of particle, PM2.5. The data appear to me to fit the PM2.5 regulatory time line as well as PM10 (which consists of larger PM, of a different chemical makeup. PM2.5 has a major regional component, PM10 less so. Strike three.
Whatever the effect of urban pollution on rainfall, this study shows nothing of the kind, because it CANNOT show anything of the kind, using national data for local effects. That was my point.
Thanks, John. My post was along similar lines, although not as admirably specific as yours.
Has anyone done the numbers for LA?
Hmmmn.
I am not at all surprised that any university generic meteorological “scientist” could be wrong given their belief system in their precious CAGW doctrine, but I am actually surprised that a Georgia State (a local!) meteorologist could be so wrong about local Atlanta-based weather events as simple as Atlanta rainfall!
At an elevation of between 980 feet and 1300 feet, Atlanta’s (northwest GA in general) rain and weather has one dominant pattern: weather comes from the west as a series of fronts coming through the low hills and pine-forested western Alabama edge of the very southern tip of the Appalachian mountains. (80% of the time. The rest of the time, we are under the west edge of the Bermuda high: very low winds, high pressures, medium cloud cover, no rains of any amount.) At that time, we get very light winds from the east, with scattered puff-balls clouds.) Atlanta’s airport, for example, has its five runways due east-west: they catch the prevailing winds either way.
NO area near Atlanta produces ANY human pollution – not now, not in the mid-1860’s (except for a few fires as a certain unnamed general fought his way through the rural south), not in the mid-1940’s, not in the mid-70’s, not in the 80’s 90’s, or 2000’s.
The ONLY “pollution” is the natural ozone from the billions (trillions?) of rapidly-growing and pollinating pine trees: Atlanta’s ozone levels are as high as any in the world due to the pine forests it is built inside of. It’s “atmosphere” is either western Alabama (equally rural) 80% of the time or eastern GA and the clean air from the mid-Atlantic after passing over South Carolina and the east Georgia mountains.
Others have pointed out the fallacy of the Nixon’s mid-1970’s Clean Act as a national factor, but not an Atlanta factor. But, to claim that west Alabama or south Tennessee is “contaminated” by particulate pollution of ANY (man-made) kind is dead wrong.
RACookPE1978:
I also tended to notice when living in Atlanta (for one year) that weather patterns would wrap themselves up around the Appalachians and head down-hill towards Atlanta, than they tended to start heading East towards the Carolinas (mostly South).
It was almost as if sometimes the storms would hug the mountain range (and yes they would be heading over Southern Tennessee and Alabama ) and head south. Yes, the amount of pollution in that area tends to be rather mild as even Chattanooga can not possibly hope to pollute as much as a major city.
The winter I was there we had 2 snow storms and both were storms caused by that. They would head in from the north and wrap around and start heading to the east after that. I also saw the problems in the study right off the bat because frankly we aren’t talking about a heavily industrialized Eastern city that does tend to get pollution in all areas, Atlanta is a central hub where all the pollution is concentrated in the center. Head away from that central area and the air is clean and crisp. Now Eastern Atlanta (metro area) (that is the area I hated) was smelly and dirty if it was over-cast. (and sometimes when it was not as well….. and you could tell that the air was the result of the city blowing air across this part of Atlanta. We lived in Northern Atlanta, and I know for a fact that most of the time we tended to have rather clean air. The only problem areas were downtown depending on the wind and Eastern Atlanta. I knew people who lived 5 miles from the airport and they too had clean air. You had plenty of noise pollution, but other types of pollution? Doubtful if it made any difference in weather patterns. To get that, you would have to look at Eastern Atlanta exclusively. But that is not from a science perspective, just someone who lived there for a year.
@Philip:
Mario Wrote:
Philip, do you believe in CAGW? This is a yes or no question. But feel free to elaborate.
Philip Wrote:
No. I think AGWism is mostly misinterpretation of a limited dataset, combined with the selling of climate models as scientific predictions, which they aren’t. And sold to a scientifically naive audience.
If you read WUWT on a regular basis, you will see that the motivation of many posters here is drag climate science back towards science.
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Well that was not expected. Now I’m really confused.
Cheers and touche’
Mario
@Joseph Bastardi June 5, 2013 at 4:43 pm:
Joe, you probably know all this, but when I first heard of the PDO over 10 years ago, one of the first things they noted was that a warm PDO was tied in with a cool continental USA – except for the SE. And cool PDO was the opposite. No attempt was made that I remember to explain why the SE would go in-phase with the PDO while the rest of the USA was inversely affected. That was all based on actual real world data. At the time I understood that they were simply trying to note down what evidence they found.
If I had to speculate, as a place to start looking for mechanisms going on, it would be guessing that the PDO affects the prevailing wind patterns/jet streams, so that the SE either does or doesn’t get prevailing wet and warm winds from the Gulf.
In my curiosity a couple of years ago, I read parts of a couple of old science textbooks from the late 1800s. It was very interesting. The authors seemed to apply the prevailing paradigms as explanations for just about everything. (SOME of those paradigms turned out to not be true, and from a 21st century POV, seeing how blithely they applied them was kind of like having a time machine and 20-20 hindsight.) This ubiquitous applying of the current paradigm seems to be still true. I think it might be just a coward’s way of doing science – you can’t get in trouble if you go along with the flow. (I used to think that only applied to bureaucrats!) It’s not just publish or perish, but publish with the right meme. How many papers have I seen that were only tangentially connected with climate, yet near the end I saw a seemingly obligatory connection with global warming.
I wonder how embarrassed some of them will be in ten or so years, to have those mentions of the by-then disproven paradigm. I can hear the lame excuses already.
I may be wrong, but that is the way I put this all together in my head.
Steve Garcia
The entire world was intimidated into claiming they actually believed and believe in this bullsh** and the only people you find around in media, STILL claim they do. It’s been the price of being popular in the eyes of men.
Those who gave into it are responsible for things such as this:
Question: you have a warm rock spinning at the bottom of a miles deep, frigid, fluid gas bath. The frigid gas bath is augmented in it’s direct contact cooling through convection and a small percentage additionally of atmospheric-pressure naturally cycling phase change refrigerant which enhances convective processes and removes additional heat.
The most typical analysis of the miles deep frigid fluid bath are those compatible with analyzing:
(A)a deep frigid fluid bath augmented with phase change refrigeration driven convectively
(B)A big, warm, blankie.
In today’s GHGE believer world, the answer your child will be taught is (B).
Thank your GHGE believer for that.
Question 2: You are warming a spinning rock by irradiating it with broad band light.
The rock has temperature, T.
You immerse and spin the rock in a fluid, gas, refrigerated bath.
The temperature of the rock, T,
will go:
(A)down
(B)up
Thanks to every single human being who endorsed the GHGE “theory” if your child doesn’t answer (B) that test question will be graded as wrong.
Hi,
I thank all of the people who have left comments for taking the time to read my paper thoroughly. As you know from reading the paper, summer rainfall totals at the nine “urban” stations (Atlanta,
Ball Ground, Covington, Dallas, Experiment, Gainesville, Newnan, Norcross, and Winder) were predicted for each of the 62 years using weighted totals at the reference stations (Athens, Cedartown,Cleveland, Curryville, Ellijay, Hightower, La Grange, Monticello, and Woodbury). Therefore, an “urban” station had an observed and predicted rainfall value for each year. The prediction procedure described above minimized the impact of interannual variability in synoptic circulation on discontinuities; therefore, the abrupt shift away negative rainfall anomalies (i.e. rainfall suppression) identified in the 1970s reflects mostly changes in the urban boundary layer relative to the rural boundary layer. In other words, PDO, global warming, etc. are certainly not the causes. I found positive rainfall anomalies in the subsequent decades, but they were not statistically significant; overlapping 30-year periods were tested for significant differences between observed and predicted rainfall totals (see Figure 4 in the paper). As I note in the paper, multiple studies have examined the effects of the Atlanta urban area on rainfall and lightning enhancement (Dixon and Mote, 2003; Diem and Mote, 2005; Mote et al., 2007; Diem, 2008; Rose et al., 2008; Shem and Shepherd, 2009; Bentley et al., 2010; Ashley et al., 2012; Bentley et al., 2012; Stallins et al., 2013), but no studies have focused on the potential impacts of changes in particulate concentrations on rainfall.
JED