Clouds amplify ecological light pollution
The brightness of the nightly sky glow over major cities has been shown to depend strongly on cloud cover. In natural environments, clouds make the night sky darker by blocking the light of the stars but around urban centers, this effect is completely reversed, according to a new study by a group of physicists and ecologists at the Free University of Berlin (FU) and the Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB).
“We found that overcast skies were almost three times brighter than clear at our rural location, and ten times as bright within the city itself,” says the lead author of the study, Dr. Christopher Kyba, physicist at the Institute for Space Sciences at the FU. Their research was reported on March 2nd, 2011, in the open access journal PLoS ONE.
“The astronomers who founded the study of light pollution were concerned with how sky glow obscured the stars on perfectly clear nights,” says Kyba, “and researchers studying the potential influences of sky glow on human or ecosystem health often cite the results from satellite measurements taken on clear nights. What our study shows is that when considering biological impact on humans and the environment, the amplification of light pollution by clouds is large, and should be taken into account.”
The study compares measurements of clear and cloudy sky brightness data taken using “Sky Quality Meters” during five months in the spring and summer of 2010. Two monitoring stations took data at locations 10 and 32 km from the center of Berlin. “Recognition of the negative environmental influences of light pollution has come only recently,” says Dr. Franz Hölker, ecologist, study author, and project leader of Verlust der Nacht (VdN – Loss of the Night).
“Now that we have developed a software technique to quantify the amplification factor of clouds, the next step is to expand our detection network. The Sky Quality Meter is an inexpensive and easy to operate device, so we hope to recruit other researchers and citizen-scientists from around the world to build a global database of nighttime sky brightness measurements.” The authors encourage those interested in participating in such a measurement to contact them at sqm@wew.fu-berlin.de.
The research was funded by two interdisciplinary projects, MILIEU (http://www.milieu.fu-berlin.de/en/index.html) and VdN (http://www.verlustdernacht.de/index.html). An interdisciplinary project of the FU, MILIEU – center for urban earth system studies, was initiated as a focus area at the FU, funded by the German excellence initiative, in order to investigate the bottom-up and top-down interactions between urban agglomerations and the climate and environment. The VdN project, funded by the German Ministry of Education and Research, is specifically devoted to quantifying light pollution and investigating its impact on humans and the environment.
Citation: Kyba CCM, Ruhtz T, Fischer J, Ho¨ lker F (2011) Cloud Coverage Acts as an Amplifier for Ecological Light Pollution in Urban Ecosystems. PLoS ONE 6(3):e17307.doi:10.1371/journal.pone.0017307
PLEASE LINK TO THE SCIENTIFIC ARTICLE IN ONLINE VERSIONS OF YOUR REPORT (URL goes live after the embargo ends): http://dx.plos.org/10.1371/journal.pone.0017307
Competing Interests: The authors have declared that no competing interests exist.
Funding Statement: This work was supported by the project Verlust der Nacht (funded by the Federal Ministry of Education and Research, Germany, BMBF-033L038A) and by MILIEU (FU Berlin). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Contact information:
Dr. Christopher Kyba
Freie Universitat Berlin / IGB
+49 30 838 71140
Available weekdays 1pm-4pm (CET), evenings possible by email arrangement
christopher.kyba@wew.fu-berlin.de
http://userpage.fu-berlin.de/~kyba/
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streetlights that are not properly shaded RUIN your night vision.
streetlights that are not properly aimed- ruin the night sky
i’m an amateur astronomer and quite honestly, i WISH that my city would turn off ALL street lights at night, in all honesty they are essentially USELESS now.
they came about due to horse and buggy’s not having lights at night
cars not having headlights
now every Vehicle on the road- except for bicycles- has headlights which more than adequately light the area in front of the vehicle to drive.
streetlights do not prevent crimes in homes- statistically most breakins occur during the day when the people are not home.
streetlights RUIN the night sky. i WANT to see all the stars in my area you can barely see orion, you CANNOT see the little dipper, etc.
plus in this cost conscious time, the money the city would save is significant if they just TURNED off the lights.
sorry pet peeve of mine.
Light Pollution has been a discussed fact for many years. I just do not see the justification to spend money to study a known problem! There are cities and neighborhoods that regulate “Light Pollution”. It is an environmental problem!
What are these “scientists” [?] on about?
What is their point about a subject which anybody with eyesight and around even a very small settlement knows that the town lights let alone a large city’s lights reflect from clouds at night. Nor do they define the so called biological effects which any shift worker can describe in detail.
And of course the mandatory mention of the “ecosystem health” which must be worth another 10% in grant money.
Thirty years ago late on a pitch black mid winter night with incredibly clear air under a total cover of low cloud over the vast flat grain fields of western Victoria in Australia’s south east I counted and identified some 20 odd towns and small settlements just from the light from each of those towns reflecting from under those low clouds.
Those towns and settlements were scattered in a radius of up to nearly 100 kms from where I stood.
And have they and Hansen with his population density for UHI purposes based on the satellite derived light intensity from city, town and settlements taken into account that Australia for instance, has a regulation that requires all street and publicly lighted venues to have a 90 degree cutoff , ie; a cover over the upper part of the light source that restricts the lighting to no more than the level of the horizon and below.
This is done for better lighting efficiency and to reduce light pollution.
Also many small settlements across Australia’s vast and sparsely settled areas and outback towns which are far removed from any grids use diesel powered electric supplies.
To conserve the very expensive diesel fuel which must be transported often some hundreds of kilometres, the street and public lighting is often switched off at around 10 pm in these small outback towns and settlements.
Both of these factors will distort any calculations which are almost invariably based on the USA experience without taking into account the often vastly different circumstances arising in other countries.
But, hey , this is Climate Science where accuracy does not matter.
Just so long as the claims of the AGW ideology can be maintained.
I’ve done a number of lighting retrofit projects for outdoor areas such as parking lots, truck and rail terminals and other similar types of areas. What I learned was that the more “light spill” from a fixture, the less efficient the fixture. In other words, the more one can keep the light on objects being lighted, the less energy required to drive the lighting system.
I’ve heard the term “light pollution” for years, but I’ve always believed the phrase came from a bunch of tree huggers. My focus has always been to provide my clients with efficient lighting systems … not green systems. As for clouds increasing the amount of light in the city … Duh!
Light pollution is one of those subtle things that everyone should consider, but few city-dwellers are at all familiar with the night sky as it should be seen, so they ignore it.
When I was a child, it was common for people to throw their garbage from fast food trips out the car windows, to blow around on the sides of the highways. I grew up in Oregon, so this rapidly became an eyesore. To the extent that you would literally get trash-drifts just like snow-drifts along the sides of the I-5. Oregonians, being a fairly qwirky bunch as environmentalists go, created a campaign called, “Keep Oregon Green”, and hence the freeways were cleaned up. I was just a kid, and this is how I remember it, perhaps someone older can add more to the story…
The point is light pollution has crept up on humans in much the same way as those drifts of trash on the side of the highway. Sure, we can get by with that trash there, but the beauty of where we exist is tarnished and lost as a result. It is true that extra light around cities can actually help. Cities that are better lit generally have fewer violent crimes against the typically victimized groups (women/children). So extra light in cities is good for humans.
I invite anyone in this thread who scoffs at light pollution being a problem to stay up a couple of nights staring at the open sky somewhere thousands of miles away from a major city. Try Alaska or South America for best results. Or if you’re a sailor, try the middle of the pacific.
I’d wager it might move some of you to tears. Yeah, we can get by with more light in cities, but do you really want our future city generations to have no concept of our place in the universe? Light pollution should be minimized whenever possible. The night sky is a treasure that inspires kids and humbles humanity.
This blog title should read “One More Pile Of Fear Mongering And Fraudulent Junk Science From Unscrupulous Money Grubbing Con/Shakedown Artists Posing As Scientists”.
But hey, maybe it is just me.
Brings this to mind.
I have stopped to give a f. because the amount of lighting screws up stargazing anyhow and adding clouds to the pot doesn’t really change the fact of urbanization one iota.
Although I think it is not too wise to use greenie street lamps since when there’s low hanging clouds those parts that use those energy saving lamps lights up like day and it screws with the birds and the rest of the wild life garbage-left-over-critters that has taking up civilization. But it’s not only the life that likes the old lights but, apparently, plants, like trees, seem to like the sodium crap better as well. So how green is it to go energy-save lighting really?
The German Excellence Initiative, really takes off.
Well, however, I mean what is the sense behing that?
If it were at least a result of too much man-made CO2 …
Oh Mie, oh my. Riccatti-Bessel Functions of the even and odd order. It was bad when I was growing up. It is absurd now anyplace near a city. Why its gotten so bad in the Boston area, we are lucky to see the sun sometimes. Walk around with SPF 30 at midnight. OK, so I exaggerate a bit, but seriously, astronomy around here is out of the question other than solar stuff. Most of it could be reduced a bit without loss to safety. You really do not need a big bright high pressure sodium lamp every couple hundred feet. Maybe something, but a high pressure sodium job burns electricity and generates way too much light to be really useful.
What a pitiable waste of thought worry over light pollution is.
Gary Hladik says:
March 3, 2011 at 4:14 pm
Keith Minto says (March 3, 2011 at 3:43 pm): ‘“Ecological light pollution” is a quality judgement and hardly has a place in the title of a scientific paper.’
Next thing you know, the EPA will go after the moon for “light pollution”. 🙂
============================================================
Then will come the taxes.
Overbearing Air Raid Warden (heard in every WWII-era Looney Tunes cartoon):
TURN OUT THAT LIGHT!!
Overbearing EPA light “pollution” regulator (coming soon):
TURN OUT THAT LIGHT!!!!
Perhaps a city could turn its street lights down a bit on cloudy nights and save the tax payers some money without reducing safety.
I thought I’d seen spectacular cloud-lit night skies in San Francisco particularly but my sense of crazy nighttime weirdness produced by airborne water increased the first time I saw a snowstorm when living at 120th Street and Amsterdam in the Morningside Heights area of Manhattan.
Snowstorms there produced a bright orange night sky in upper Manhattan as I have never seen elsewhere.
researchers studying the potential influences of sky glow on human or ecosystem health often cite the results from satellite measurements taken on clear nights. What our study shows is that when considering biological impact on humans and the environment, the amplification of light pollution by clouds is large, and should be taken into account
It would be nice if they actually qualified that “biological impact” by citing examples and quantified the effect of the amplification of light pollution. Are they saying summer in the far north/south or full-moon nights are bad for humans and the environment? I mean, the midnight sun is about as much light pollution as you can get, right?
Yes, there’s light pollution. Personally, I like stargazing, but I find light pollution comes in handy when walking along an unlighted street during a moonless night. It lets me keep a distance between myself and any unleashed dogs or potential muggers. So until they come up with something more than handwaving about “negative environmental influences of light pollution,” I’ll take urbanization and prosperity. Thank you.
Please tell me this is an early April Fools day joke. Or an episode of the Simpsons. Or maybe a really bad reality TV show. This can’t be serious research.
Re biological impact: in Perth, Western Australia, and no doubt in other cities on the coast, seagulls work at night feeding fon the moths circling the street lights. Don’t know if they sleep during the day but their night-time feeding stations are probably more efficient in providing food, so they could just stand on one leg and put their head under their wing.
I am certain there is increase in car break ins, assault, rape, mugging, hit by cars, when there is no street lights.
If you like looking at stars that much you can sell your house in the city and move to a remote countryside home.
For all those unfamiliar with this issue, it is very real and not trivial. Please visit the International Dark Sky Association to learn more:
“IDA is the recognized authority on light pollution. Founded in 1988, IDA is the first organization to call attention to the hazards of light pollution, and in 22 years of operation our accomplishments have been tremendous. We promote one simple idea: light what you need, when you need it. We know some light at night is necessary for safety and recreation. We work with manufacturers, planners, legislators, and citizens to provide energy efficient options that direct the light where you want it to go, not uselessly up into the sky.”
http://www.darksky.org/mc/page.do?sitePageId=90127&orgId=idsa
This is a major problem not only for astronomers, but everyone as bright night skies impact your health (affecting circadian rythms, melatonin production, eyes, etc.), wildlife, not to mention study after study have shown more light doesn’t drop crime etc. but just wastes energy and money.
The night sky is as much a part of the natural environment as any other and deserves protection. Today millions upon millions growing up in the cities have never even seen the Milky Way or a truly dark sky and people are as awed by a spectacular star studded dark night sky as they are when they see other natural wonders.
“plus in this cost conscious time, the money the city would save is significant if they just TURNED off the lights.
sorry pet peeve of mine.”
Where I live it’s pitch black outside unless there is a bright moon and no clouds. I’m in the middle of nowhere, though, so this is generally not a problem.
The city is a different story. Do you truly not realize what you’re asking? I can’t honestly believe that you do.
Chicken little: “The sky is clouding! The sky is clouding!”
James
We need to cut these people off. Like many others, I figured this out long, long ago and nobody took taxpayer money and gave it to me.
This just in: When you pile garbage from the city into a big pile, it stinks to high heaven!
Ah yes, more worried about heat than cold, more worried about light than darkness. I remember back when society was misguided and thought that the discovery of fire was actually a good thing.