Light pollution--stupid question for DU environmental scientists

[Skidmore]

You know that picture of the globe with the US lit up like Vegas that was around on the web? Okay, I have this stupid question about the amount of heat we put out to keep...well...Vegas, your local strip mall, your local car dealership, etc. all lit up. When we moved out to our little village from a larger town, the first thing I noted was that I could actually see the stars at night again--something that I hadn't been able to do in years. I've been much more cognizant of light pollution now for several years, but I'm also assuming that all those lights also means heat dispersing in the atmosphere.

1) How much does this "heat pollution" contribute to global warming?
2) Is there a national effort to reduce this type of pollution?
3) Why do we need to have so many freakin' lights in this country? Americans alway overdo everything excessively.

[skids]

1. Heat pollution

1) Heat pollution like this doesn't really have much of an effect on global warming. Consider that during the day, a square meter of black dirt or pavement puts out a steady 1000 watts, and consider how much dirt we have -- not all of it black, but we have a lot of ground.

Where heat pollution matters is when a lot of heat is rejected from, say, a power plant into a localized area, especially a body of water. Oh, and where we get the electricity and how much CO2 and other pollution is generated in the process, of course.

2) There is no effort to reduce light pollution but there is a move on to use streetlights that reflect all their light downward, more to save electricity by using the wasted light than to reduce upward emissions, perse.

3) We have so many lights in the country that a large percent of the population has lost their night vision due to atrophy. This adds to the problem because those same people then tend to want every room brightly lit, not to mention crave annoyingly bright headlamps on their cars. Why? I don't know.

[Spider Jerusalem]

2. It's not JUST this country.

Here's a view of the whole planet: antwrp.gsfc.nasa.gov/apod/image/0011/earthlights2_dmsp_big.jpg

Western Europe is about as lit up as the Eastern US; the US looks brighter, mainly because of the Northeast Corridor from Boston down to Baltimore, but there's not THAT much difference (and what difference there IS can probably be attributed to the fact that there are a lot of 24-hour businesses in most US cities, etc; while there aren't in Europe). If you look at the map and have a decent knowledge of geography, you can pinpoint major cities based on light output; another interesting thing is that you can trace the route of the Trans-Siberian railway from Moscow to Vladivostok, because it shows up as a thin strand of light.

Really, the vast expanses of deforsested pavement and solar reflection from same are probably a much larger source of heat pollution.

[bananas]

3. a cool website for stargazing

predicts how clear the sky will be over the next 2 days
http://cleardarksky.com/cgi-bin/find_clock.py?Mn=focuser&type=wmap&radius=60&unit=1&disp=text&title=Clocks+within+60mi+of+Las+Vegas&olat=36.175&olong=-115.136

[EST]

4. There was a Scientific American article about this, dealing

mainly with light pollution and the effort going on to use a different type of light bulb, of a lower power consumption, and a different spectrum, down directed. The problem, from their point of view, is that some observatories are becoming almost useless because of the amazing amount of light we create.

The amount of electricity this consumes was stunning. This, as I'm sure you recognize, represents a sizable slice of global warming influence.

I'll try to dig it up and drop it in here.

[Skidmore]

5. Thanks, I'd love to see that article.

[rman]

6. Cities put out enough heat that they are called "heat islands"

http://eetd.lbl.gov/HeatIsland/LEARN/

[Fox Mulder]

7. To answer question #2:

Yes, there is a national effort to reduce light pollution. I think you may be interested to read this article from Astronomy.com: http://www.astronomy.com/asy/default.aspx?c=ss&id=87

IDA (International Dark Sky Association)'s website: http://www.darksky.org/

[Skidmore]

8. Thank you much for the article, and I'm totally impressed that

Fox Mulder visits DU!! :)

[Fox Mulder]

9. Haha.

I wish I was the real Fox Mulder.

:P

[EST]

12. To give you a handle on the big picture, a little googling

got me a number on total power production.

In 2003, approx 42,000,000,000,000-that's forty two thousand billion or forty two trillion--kilowatt hours used globally, about 25% used for lighting. Cool numbers to piddle around with. With new technology, intelligent street lighting, and intelligent design (URK!) reducing that number by half could reduce the shock of population explosion and concomitant global warming considerably.

It all becomes heat--generating, cooling, the light energy, itself, the heat produced by all the losses in the circuits and the lamps.

A horsepower is about three quarters of a kilowatt.

A human being puts out about as much heat as a 100 watt light bulb.

[LiberalEsto]

10. There is some kind of effort

but it's not well-funded, from what I gather. About 10 years ago I accompanied the class of one of my kids on a field trip to a planetarium at Montgomery College in Takoma Park, MD.

The museum tour folks did a nice job of explaining the issue of light pollution. Here's a link to the college planetarium website: http://www.montgomerycollege.edu/departments/planet/

[greenman3610]

11. seeing stars makes people wonder

[DemoTex]

13. As an amateur astronomer, I'm often shut-down by light pollution.

When I first moved to Dallas in 1996, I marveled at the pristine night skies .. even in the city. With clean air, light pollution is not as noticeable. However, after a few years of "voluntary" clean air compliance under Governor George Bu$h, the north Texas air became as foul as that found in the Houston area. The increase of particulate pollution in the air exacerbated the light pollution problem. Light (often gratuitous, vain, "landscape" lighting) reflected from some of the growing number of components of the air pollution, and the result, by about 1999, was a night sky that, most often, defied star gazing.

Fast forward to 2003 when I bought a mountain house in western North Carolina. It was star gazer heaven! Pristine night skies ruled. The only light pollution was from the moon! That started changing quickly however, as federal air quality standards were attenuated by - who else? - George W. Bu$h. The Appalachian and Blue Ridge Mountains are downwind (prevailing westerlies) from the coal burning power plants of the Tennessee River Valley. The pollution from this high sulfur coal (called brimstone in the Bible .. the stuff hell is made of) forms sulfuric acid when mixed with water in the form of rain, snow, or even dew. The result has been a alarmingly rapid deleterious effect on the forests of the region. The high-mercury discharge levels from these power plants, OK now under Bu$hco, pollutes the water, poisons the fish, and presents significant health hazards to all flora and fauna, especially the human species.

Now, in the mountains, one can expect weeks and weeks of stagnant, choking, eye-burning air in the summer months. It takes a strong cold front to clear things out enough to use a telescope. Temperature inversions in the winter will fill the valleys with the foul, almost fog-like air, while the mountain tops and ridge lines sometimes (but not always) enjoy cleaner air. Again, it often takes a strong cold front with brisk northwest winds to clean the soup out enough to venture out for an evening of star gazing (but then, usually bundled against sub-zero chill factors).

As to any heat generated by light pollution, I would guess that it is relatively insignificant when compared to the heat generated in producing the power needed to illuminate all that light. But, as instructed by thermodynamics, every little bit .. in this case .. hurts.