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Science

More on Global Dimming 379

Posted by michael from the future's-so-dark-I-don't-need-to-wear-shades dept.
dtolman writes "According to the New York Times (registration required) if the world seemed brighter to our grandparents 50 years ago, they were right. While the sun's output hasn't dropped, the amount of sunshine reaching the Earth's surface has dropped an average of 10% since the 1950's. In Hong Kong, the sunlight reaching the surface has decreased even more - 37%! Scientists are theorizing that this is mainly due to air pollution - so this trend might reverse if air pollution clears up." We had a another story on global dimming last year.
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More on Global Dimming

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  • Almost had me (Score:5, Funny)

    by metlin ( 258108 ) * on Thursday May 13, 2004 @11:57AM (#9140958) Journal
    For a second there, I was under the impression that this was a study on the intelligence of humans.

    *whew*

  • Frustrated (Score:5, Informative)

    by DarkHelmet ( 120004 ) * <.mark. .at. .seventhcycle.net.> on Thursday May 13, 2004 @11:57AM (#9140962) Homepage

    Here [trivalleyherald.com] is a copy of the exact same news story that does not require a registration link.

    Stories like this are typically SYNDICATED, which means that you can find the exact same thing in 50 or so other newspapers, right?

    Why, oh why, do people choose to link to a page that requires registration when it's totally unnecessary?

    Finally, does this remind anyone else of the Animatrix, on how the skies were darkened to stop the machines?

    • Finally, does this remind anyone else of the Animatrix, on how the skies were darkened to stop the machines?

      Heh, that remembers me one of the Murphy's law: don't attribute to malice (i.e. darkening the skies to kill sun-dependant machines) what can be explained by stupidity (i.e. letting the smog/contamination/etc steal our sun, kill us, etc)

    • Re:Frustrated (Score:5, Flamebait)

      by OverlordQ ( 264228 ) * on Thursday May 13, 2004 @12:09PM (#9141132) Journal
      There's an easy way [calpundit.com] to get the no-reg archive link so why link to a podunk newspaper when it's totally unnecessary?

    • Re:Frustrated (Score:2, Insightful)

      by NanoGator ( 522640 )
      "Why, oh why, do people choose to link to a page that requires registration when it's totally unnecessary? "

      Because most of us don't give a flying fuck and just registerred with them. Seeing as how they don't send spam etc, it's a small price to pay for a free service.

      This crusade against NYT is redudant, lame, and very tiring. More embarrasingly, they don't even check to see if you have a valid email. You want to complain about a site? Go glance around IGN.com. Bet you find at least 5 things to b

    • Re:Frustrated (Score:4, Insightful)

      by dtolman ( 688781 ) <dtolman@yahoo.com> on Thursday May 13, 2004 @01:11PM (#9142041) Homepage
      Perhaps because I read it on the front page of my physical New York Times first?

  • I can attest to this. (Score:4, Interesting)

    by Power Everywhere ( 778645 ) on Thursday May 13, 2004 @11:58AM (#9140967) Homepage
    In the area i live alone, my father has remarked several times in the last five years how either his eyes have gotten used to the sun after almost sixty years, or that things are a lot dimmer -- he used to wear Blueblockers religiously but now doesn't even keep a pair around.

    • Re:I can attest to this. (Score:2, Informative)

      by Anonymous Coward
      Humans' eyes' lens are going to become more opaque with age, and I'm sure there's some retina degeneration going on.
    • Well duh!

      This science experiment is silly. I could have told them about the global dimming thing. Just compare the Beatles "Abbey Road" with a google search of "london". It's much darker over there now than it was when the Beatles released that album.

  • Let's just get this out of the way... (Score:5, Informative)

    by bloggins02 ( 468782 ) on Thursday May 13, 2004 @11:58AM (#9140972)
    Before anybody asks the question we know you want to ask:

    There's heat, and then there's visible light. They ain't the same thing.

    Just because it's "dimmer" doesn't mean it isn't getting warmer.

    There, I feel better.
    • There's heat, and then there's visible light. They ain't the same thing. Just because it's "dimmer" doesn't mean it isn't getting warmer.

      But if dust and grime catch the energy instead of the ground, then isn't the radiation more likely to be radiated out into space, cooling the planet? If the energy hits the ground, then in order to bounce back into space it has more layers of air to pass back through, which would grab that energy instead of letting it all go into space.
      • It was my understanding that the longer wavelengths of heat can pass right through smaller objects such as dust particles, where they eventually strike the ground and warm the Earth's surface.

        These "long waves" are radiated back from the ground, which generates most of the heat we feel.

        However, if the long waves go right through small particles, it doesn't explain why clouds tend to act as thermal blankets.

        Anybody who knows more about this stuff care to help us out?

        (Adding Karma bonus to increase chance
      • Actually, the pollution tends to let the heat through but then trap it.
      • I could be wrong but I believe the very thing that is preventing light from coming through (more ozone) is also insulating the earth to warm it up ... and cause global warming.
      • In a word, no.

        What you end up with is scatter from the smaller particles. Light hits them, and is radiated back as heat, in ALL directions. Both the light and heat are then scattered in all directions by other particles in the air. (the degree of reflection/absorption-radiation of the particles has a significant effect on the degree of heat radiated)

        This creates a warmer 'boundary layer' that reduces the amount of heat given up by lower layers of the planet, so even if those lower layers get less energ

      • Re:Let's just get this out of the way... (Score:5, Informative)

        by hak1du ( 761835 ) on Thursday May 13, 2004 @12:29PM (#9141438) Journal
        But if dust and grime catch the energy instead of the ground, then isn't the radiation more likely to be radiated out into space, cooling the planet?

        If they "catch" the energy, they reflect a little bit as visible light and convert most of it into heat. Part of that heat gets radiated back into space and part heats up the surrounding air. The overall effect seems to be a significant contribution to global warming.

        Global warming models take this effect into account. However, particulates are not as much of a concern for global warming because, unlike CO2, they disappear from the atmosphere fairly quickly (they are still a huge health concern, however). With CO2, once it's released, we are stuck with the consequences for a century or two. Furthermore, global dimming reduces photosynthesis, further slowing down the removal of CO2 and worsening the problem.
    • Okay, but it's still possible that the two effects tend to balance each other out (somewhat).

    • Re:Let's just get this out of the way... (Score:5, Insightful)

      by hak1du ( 761835 ) on Thursday May 13, 2004 @12:18PM (#9141269) Journal
      Just because it's "dimmer" doesn't mean it isn't getting warmer.

      Actually, it may be getting warmer because it is getting dimmer: if visible light is absorbed by something in the atmosphere, it would end up heating up the atmosphere. Think of a black solar collector used for water heating.
    • OK. But I have a question. At what point does more "stuff" in the air have a cooling, rather than warming effect? We've talked for years about a "nuclear winter" wherein the dust, soot and smoke kicked up by a nuclear war would block out the sun and cause the Earth to cool.

      IOW, at some point, less light does equal less heat.

    • Re:Let's just get this out of the way... (Score:5, Informative)

      by praedor ( 218403 ) on Thursday May 13, 2004 @12:34PM (#9141493) Homepage

      Wrong. If the earth's albedo is increasing, and it is high-altitude, then a decrease in sunlight reaching the earth's surface would likely follow along with a decrease in temperature (as sunlight would be reflecting away from earth). I have read nothing about an ever-increasing albedo, and the articles on the subject indicate ABSORPTION of visable light is the cause of dimming at the surface. Absorption WILL produce heat. The energy of the sunlight doesn't disappear upon absorption, it gets converted into heat (and molecular kinetic energy). Energy can neither be created nor destroyed, merely converted into a different form. VISABLE sunlight energy is down-convertedinto infrared energy (heat). It leads to an increase in temperature with increasing dimming.

  • A fix!? (Score:3, Funny)

    by Tablizer ( 95088 ) on Thursday May 13, 2004 @11:58AM (#9140977) Journal
    We can fix global warming by polluting the atmosphere more? Too good to be true. What's the catch?
    • What's the catch?

      If the atmosphere contains more polution, we get less light but the atmosphere actually warms up more. As someone else said, light != heat.
      • If the atmosphere contains more polution, we get less light but the atmosphere actually warms up more. As someone else said, light != heat.

        Except that in this case, "light" is measured with a radiometer-- basically a black-painted metal plate with a thermometer-- so radiant heat is very much a part of this equation.

  • Rehashed (Score:4, Informative)

    by andy666 ( 666062 ) on Thursday May 13, 2004 @11:59AM (#9140992)
    Every few years this gets brought up. There was an article in the June 94 sci american about it. The topic is a bit of a yawner anyway.

  • Looks like we'll all be dead... (Score:3, Insightful)

    by Neil Blender ( 555885 ) <neilblender@gmail.com> on Thursday May 13, 2004 @11:59AM (#9141002)
    ...the day after tomorrow. Next time an asteroid movie comes out, expect plenty of articles about about that in the media.

  • In other news... (Score:5, Funny)

    by Anonymous Coward on Thursday May 13, 2004 @11:59AM (#9141003)
    Future not so bright, shades no longer required.
  • more on global dimming here [about.com]

  • Less light - more heat? (Score:4, Insightful)

    by drizst 'n drat ( 725458 ) on Thursday May 13, 2004 @12:00PM (#9141021)
    Ok ... so less light is reaching the surface than did 50 years ago though the energy output has remained relatively the same. Is it safe to assume that the energy is being absorted by pollution and thus heating the planet?
    • Some of it could be getting reflected back into space, say by increased cloud cover.

    • Re:Less light - more heat? (Score:4, Insightful)

      by rrkap ( 634128 ) on Thursday May 13, 2004 @01:19PM (#9142137) Homepage

      Is it safe to assume that the energy is being absorted by pollution and thus heating the planet?

      Not really. The question is one of total energy ballance.

      Think about it as (mass)*(heat capicity)*(temperature change)=(incoming energy from radiation)-(reflected energy)-(re-emitted energy)

      The atmosphere could be becomming more reflective, too. The mechanism proposed for global warming ignores this in its simplest form. CO2 is pretty transparant to visible light, but likes to absorb heat, meaning that the total emissivity of the earth is assumed to be being reduced at long wavelengths and left the same at short ones. This research says that something is happening at the shorter wavelenghths as well.

  • Could someone explain how we know that less light is reaching the surface now? What accurate instruments were we using 100 years ago that gave us a solid baseline to compare against? Also, how were we accurately measuring solar output, which can be pretty variable?

    Is the surface of the earth really receiving less light, or are we just better at measuring it?

  • I smell oportunity... (Score:4, Funny)

    by Spatula Sam ( 770957 ) * on Thursday May 13, 2004 @12:02PM (#9141041)
    Quick! Invest in lightbulb manufacturers!

  • Some else of interest (Score:5, Interesting)

    by spuke4000 ( 587845 ) on Thursday May 13, 2004 @12:03PM (#9141049)
    An unrelated, but similar phonomenon is that of the effect of jet contrails on temperature. You can read about it here [cnn.com]. The study used the period after 9/11 when all flights in North America were grounded for a few days. An interesting read.
    • So Al-Qaeda goals was sacrifice a relatively small amount of people to show us all the climate damage of airplanes? Putting separate facts together could make people associate things in wrong ways.

      But seriously, if airplanes do such impact on worldwide climate, why not exist a technological race to make them more ecological instead of faster, more personal, to reach higher or things like that? Or some advancements are done in that direction?

  • Oh crap. (Score:2, Insightful)

    by Elpacoloco ( 69306 )
    Plants get their energy from the sun's light. Insufficient light means no plants. No plants means no food. (Meat isn't plants, but it's powered by plants, so no plants, no meat either.)

    One unfortunate thing about polution is that the wind blows it everywhere. A coal factory darkens the skies in antartica no matter if it's location is in Denver, Stockholm, or Bejing.
    • Doesn't the Earth's rotation in fact tend to distribute pollution toward the poles? (This would explain the large ozone hole over the South Pole...)

    • Re:Oh crap. (Score:2, Insightful)

      by cavemanf16 ( 303184 )
      One unfortunate thing about polution is that the wind blows it everywhere. A coal factory darkens the skies in antartica no matter if it's location is in Denver, Stockholm, or Bejing.

      Really? I didn't know fumes from a smokestack in Denver, Stockholm, or Beijing could be auto-magically multiplied to effectively blanket an entire continent in a swatch of life-choaking pollution. C'mon people, stop believing the FUD! You don't like it when Microsoft does it to your precious Linux, why be any different about
    • Well good! If this trend continues, I'll be able to use my 1000 watt grow lamps to make money growing legal plants!

  • Good thing? (Score:3, Insightful)

    by typobox43 ( 677545 ) <typobox43@gmail.com> on Thursday May 13, 2004 @12:05PM (#9141082) Homepage
    Isn't global dimming a good thing? Sunlight isn't exactly compatible with the nerd life...

  • Pollution, or... (Score:2, Funny)

    by Anonymous Coward
    To all those eco-freaks, it's not pollution. It's mood lighting.
  • In some areas, air quality has improved since the 1950's. When I grew up in Los Angeles, there was a lot more pollution than now. Does that mean the sun should be brighter there than in the past?
  • to make sure that solar energy will never be cost-effective. Clever, but diabolical.
  • On a more serious note, try a search for '"september 11" contrails' on a search engine. It was established that due to the absence of contrails in the air, more sunlight reached the USA, and it even warmed up a little as a result over the 3-4 days.

    Could still be a fluke, but the chances of that are phenomenally low.

    • Re:Particulate matter scatters light, news at 11! (Score:5, Informative)

      by Chmcginn ( 201645 ) on Thursday May 13, 2004 @12:26PM (#9141384) Journal
      On a more serious note, try a search for '"september 11" contrails' on a search engine. It was established that due to the absence of contrails in the air, more sunlight reached the USA, and it even warmed up a little as a result over the 3-4 days.

      Wrong. (Not just because you're too lazy to provide any links. You know, like this [cnn.com] or maybe this [newscientist.com].)

      No, you're actually wrong because you fail the reading (and understanding) the articles test - it didn't warm the earth up. It increased the temperature range for each day - that is, both the high and the low temperature - just like a clear day versus an overcast one.

  • When Bored Scientists Attack (Score:3, Interesting)

    by Morphy3 ( 227773 ) <morphy3@y a h o o . c om> on Thursday May 13, 2004 @12:09PM (#9141133) Homepage
    Global Cooling
    Acid Rain
    Global Warming
    Global Dimming
    http://www.junkscience.com
    • Experts may disagree about the extent of global warming and human-induced climate change, but few can dispute that we are changing the planet's atmosphere in measurable ways. There is objectively more carbon dioxide and pollutants in general floating around. One is hard-pressed to claim that these will not have ANY affect on weather. The left/right fights are over what the specific changes are.

      There seems to be a recent up-ward warming trend. If this trend continues, it will cause economic problems such as
    • What a whacked-out site. You, sir or madam, have been sucked in. And what do all these things have in common? Proposed solutions or mitigation measures could have an impact upon those who put profit above all other considerations.

      The way we live now is unsustainable. Sorry if you can't adapt, but things are going to change - voluntarily and gradually, or more quickly and catastrophically. Ideological ostriches disguising themselves as rational voices of scientific dissent aren't helping matters.

      Acid rain
  • My view of the future just got darker...

  • Headlines We Should be Wary Of (Score:5, Insightful)

    by basking2 ( 233941 ) on Thursday May 13, 2004 @12:10PM (#9141155) Homepage

    So, after the ice age coming back, global warming destroying us, acid rain eating us and the oil supply being exhausted by 2010 I take science headlines with a grain of salt. The fact that this is from the NY Times just furthers my suspicion. That paper has destroyed its reputation over the years.

    One thing that folks have to realize is that scientists are people. They get happy and sad, they are humble and proud, and they lie, steal, cheat and grab for headlines as reagularly as any normal person would.

    This is not to discredit the publishers of this work, but to remind us all that headlines like this pop up often amount to a new natural trend or in the very rare case, us acctually damaging the environment in a way that it isn't designed to cope with.

    I mention this because our geek culture has a way of worshiping the words of scientists and as a result some amusing lies have drifted in and out of school text books and around our little digital communities. Trust no one. The truth is out there. Now will I get sued by Fox or the aliens over Mexico??? Hmmm...

    • Re:Headlines We Should be Wary Of (Score:2, Funny)

      by Anonymous Coward

      One thing that folks have to realize is that scientists are people. They get happy and sad, they are humble and proud, and they lie, steal, cheat and grab for headlines as reagularly as any normal person would.

      This is not to discredit the publishers of this work,...

      No, of course not. How could someone have misinterpreted what you wrote in the paragraph above as badmouthing scientists? Sheesh!

    • Re:Headlines We Should be Wary Of (Score:2, Insightful)

      by Anonymous Coward
      In regards to the oil supply running out, just be aware that even oil industry execs believe in Hubbert's Curve. It's just that they take the short-term view that an decrease in supply with the steady increase in demand will increase their profits over the short term.

      I just read an article that interviewed some oil industry execs in Oil and Gas Journal, in fact, where they said just that.

      It's morally reprehensible, of course. But the wider point is that Hubbert isn't a junk scientist. He worked for She
    • The headlines seem to be the problem. If you read down just a little ways, it appears that this is being discussed at a convention as an area for further research. Also, there is some healthy skepticism from scientists regarding the issue:

      Not every scientist is convinced that the dimming has been that pronounced. Although radiometers are simple, they do require periodic calibration and care. Dirt on the dome blocks light, leading to erroneous indications. Also, all radiometers have been on land, leaving

  • So... global warming and lots of toxic clouds. We're turning into Venus!
  • "so this trend might reverse if air pollution clears up."

    Ultimately all of our energy comes from the sun, and solar power (wind included) contributes the least pollution to the atmosphere. It's like the fossil fuels are directly hurting the competition. Cutting the output of solar cells 10% is like setting them back years. Strange.

  • Ugh (Score:2, Insightful)

    by cavemanf16 ( 303184 )
    Ok, so scientists are pissed off about the following things:

    1) Global warming: It's getting hotter!
    2) Global dimming: It's getting darker!
    3) Global light pollution: It's too bright at night!
    4) Global noise pollution: It's too noisy!

    Why don't we all stop bemoaning all the crap that's supposed to have killed us within 10 years over the past 50 years and just get back to doing something useful with our time. Measuring fractions of changes on a global scale is like stating that my Linux server crashed because
    • ...every hour to monitor my stocks and commodities. It would download the latest prices every hour. But they suddenly changed the format that the data was represented in and they occasionally added extra significant digits to the prices. Most commodities went through fine but when it reached Chinese tea the extra digit caused a buffer overrun in my code and it went into an infinite loop. The problem is, my cron job was expecting to see a return code, and when it didn't get one, due to a bug in my script it
    • "Measuring fractions of changes on a global scale is like stating that my Linux server crashed because of the price of tea in China yesterday!"

      I wish I could find that damn butterfly that keeps causing all those unforseen outages.

  • Worst of both worlds... (Score:3, Interesting)

    by mark-t ( 151149 ) <markt AT nerdflat DOT com> on Thursday May 13, 2004 @12:24PM (#9141353) Journal
    So let me get this straight.

    Because of pollution, not only are more X-rays and UV getting through, increasing the rates of skin cancer and other problems, but we've also reduced the actual amount of visible light reaching the earth???

    Wow... why screw up only one thing, when you can screw up two at no extra cost?

  • the article submitter, dtolman [geocities.com] wrote:

    Scientists are theorizing that this is mainly due to air pollution - so this trend might reverse if air pollution clears up.

    If only air pollution would just clear up by itself, then we'd all be happy. Heaven forbid that anyone should have to actually do anything to clear up pollution. That might actually require thought, effort and sacrifice.

  • So how long... (Score:3, Funny)

    by Iscariot_ ( 166362 ) on Thursday May 13, 2004 @12:27PM (#9141394)
    So how many years before Highlander 2?...

  • Air pollution is not strictly a recent phenomenon (Score:5, Informative)

    by kjfitz ( 256432 ) on Thursday May 13, 2004 @12:27PM (#9141407) Homepage
    There is a common misperception that air pollution is a recent thing.

    This from Environmental History Timeline [radford.edu]:


    • 1661 -- John Evelyn writes "Fumifugium, or the Inconvenience of the Aer and Smoake of London Dissipated" to propose remedies for London's air pollution problem. These include large public parks and lots of flowers. http://users.synflux.com.au/~ant/Evelyn/fumifug.ht ml http://www.accd.edu/sac/english/bailey/evelyn.htm

      "The immoderate use of, and indulgence to, sea-coale in the city of London exposes it to one of the fowlest inconveniences and reproaches that can possibly befall so noble and otherwise incomparable City... Whilst they are belching it forth their sooty jaws, the City of London resembles the face rather of Mount Aetna, the Court of Vulcan... or the suburbs of Hell [rather] than an assembly of rational creatures..."

      In his diary, Evelyn writes in 1684 that smoke was so severe "hardly could one see across the street, and this filling the lungs with its gross particles exceedingly obstructed the breast, so as one would scarce breathe."


    And this from Air Pollution [fofweb.com]:


    • In the Middle Ages London air was so polluted by smoke from coal fires that in 1273 Edward I passed a law banning coal burning in an attempt to curb smoke emissions. In 1306 a Londoner was tried and executed for breaking this law. Despite this, pollution was not checked, and on one occasion in 1578 Elizabeth I refused to enter London because there was so much smoke in the air. Smoke killed vegetation and ruined clothes, and the acid in it corroded buildings.


    I always wondered if this early pollution may have contributed to Europe's mini-ice age [stanford.edu]

  • They convinced everyone that wearing sunglasses indoors and at night was "cool".

  • We Need Global Dimming (Score:4, Interesting)

    by SoopahMan ( 706062 ) on Thursday May 13, 2004 @12:32PM (#9141476)
    That previous story on Slashdot included Dimming's relation to Warming - in particular, scientists suspect Mars lost its water in a disastrous event called a "Hot Spot," where one point in the ocean reaches so high a temperature that it begins evaporating so fast it actually magnifies the sun's heating effect at that surface point - causing nearly all the ocean to leave the planet through that spot.

    Dimming was suggested as the reason this has not occurred - that although heat is up, average sun exposure to the surface is down, and so, evaporation is down too. The net effect is a constant level of evaporation despite rising temps.

    So - is Dimming the buffer that keeps the Earth alive during times of Global Warming? Or is it possible to lose Dimming and keep Warming, rendering us as waterless as Mars? Or, is the Hot Spot theory just hot air in the first place?

  • Warming... (Score:2, Funny)

    by ronchie02 ( 690654 )
    Pollute more! It will prevent global warming! :P
  • you can sign up for an Indie-Mail (link in sig) account without an existing e-mail account and without giving any private information.

    What information you give the NY Times is up to you.

    Ben
  • We need Mario! That's what we need! He can go around cleaning up glop, and collecting Shines, thus increasing the output of our sun!
    Shine Get!

  • Sounds romantic (Score:4, Funny)

    by saddino ( 183491 ) on Thursday May 13, 2004 @01:01PM (#9141908)
    First "global warming and now "global dimming."

    We're getting cozy, dimming the lights...all we need is "global barry white" and -- BAM -- human population explosion at your service.

  • Coal - effects on light (Score:5, Informative)

    by guacamolefoo ( 577448 ) on Thursday May 13, 2004 @01:03PM (#9141936) Homepage Journal
    The folks in Pittsburgh during industrialization are familiar with the loss of sunlight. So were those in London and Manchester in England during industrialization there. The "English Disease", or rickets, resulted from low levels of vitamin D production due to a lack of sunlight attributable in part to (1) long working hours out of the sun and (2) particulate pollution from burning coal.

    An interesting book that deals, in part, with that is Coal: A Human History [amazon.com]. Also available here [google.com] or from your local library.

    GF.

  • fun fact (Score:4, Informative)

    by kisak ( 524062 ) on Thursday May 13, 2004 @02:17PM (#9142853) Homepage Journal
    The US contains 4 % of the total world population and is behind 25 % of the world's total green house gases production.

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