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Global Dimming 637

wiredog writes "The Guardian reports on research which shows that the amount of sunlight reaching the Earth's surface has decreased by 10% in 30 years. This has implications for global warming models and, especially, agricultural output."
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Global Dimming

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  • by Cr3d3nd0 ( 517274 ) <Credendo AT gmail DOT com> on Thursday December 18, 2003 @10:03AM (#7753950)
    I would say this is directly linked to our obesity problems

    badum DUM
    • Don't forget breast implants...
    • by pixelpusher220 ( 529617 ) on Thursday December 18, 2003 @10:29AM (#7754248)
      I thought it was a commentary on the last US Presidential election...

      "1000 points of light...and we get the dim one"

    • How old is Darl McBride again? The world does seem to be getting dimmer since he's around.
    • Re:Well of course (Score:5, Interesting)

      by rrkap ( 634128 ) on Thursday December 18, 2003 @11:32AM (#7754894) Homepage

      Although you probably meant this as a joke, it might be. The amount of light people recieve affects lots of physical things. Chronically light deprived people (such as those who work night shifts) are heavier on average than those who don't. Lack of sufficient light also affects alertness and mood, and not only in those who have seasonal affective disorder.

      That being said, I don't think a 10% reduction in light would cause a significant increase in obesity, but it might be an interesting experiment.

      • Re:Well of course (Score:5, Insightful)

        by zCyl ( 14362 ) on Thursday December 18, 2003 @11:54AM (#7755170)
        Although you probably meant this as a joke, it might be. The amount of light people recieve affects lots of physical things.

        In laboratory animals, chronic consumption of preservatives and free glutamate affects the hypothalamus and causes obesity, among a large number of other problems. The amount of this in our food has skyrocketed enormously over the last 50 years. In certain countries, such as the US, we eat nearly toxic levels of these compounds without taking notice.

  • by circletimessquare ( 444983 ) <> on Thursday December 18, 2003 @10:04AM (#7753958) Homepage Journal
    my landlord told me not to touch that dial on the wall, but i couldn't resist

    i'll set it back to the way i found it
  • So instead (Score:2, Interesting)

    by flafish ( 305068 )
    of Global Warming, we have to worry about Global Cooling. Is that why it is 45F out in S. Florida? :-)
    • Re:So instead (Score:5, Insightful)

      by WindBourne ( 631190 ) on Thursday December 18, 2003 @10:06AM (#7753986) Journal
      No. The amount of sunlight reaching earth is still the same. The amount reaching the ground is what is decreasing. It is being absorbed elsewhere or being reflected.
      • by Anonymous Coward
        No. The amount of sunlight reaching earth is still the same. The amount reaching the ground is what is decreasing. It is being absorbed elsewhere or being reflected.

        It's all these damn enviro-hippies and their solar power! They're sucking in all the light that used to hit the ground and keep the earth warm. STOP IT.

      • Re:So instead (Score:5, Informative)

        by Glock27 ( 446276 ) on Thursday December 18, 2003 @10:37AM (#7754337)
        No. The amount of sunlight reaching earth is still the same. The amount reaching the ground is what is decreasing. It is being absorbed elsewhere or being reflected.

        Not quite right either. The amount of sunlight reaching the top of the Earth's atmosphere is still the same. The amount reaching the ground is over 10% less than during the 60's. It is not clear how much of the sunlight is being absorbed and then re-emitted as IR within the atmosphere, and how much is being reflected back into space. Snow and clouds both reflect a lot of energy back out of the atmosphere. You mention reflection, but you don't seem to think it could result in net energy loss.

        What I'm trying to get at is that if some factor (say cloud seeding from aircraft exhaust, a known phenomenon) is causing more cloud cover, it could well be that the total solar energy absorbed by the ground+atmosphere is substantially less than it used to be. The article wasn't clear on this point.

        • Re:So instead (Score:3, Interesting)

          by Becquerel ( 645675 )
          cloud seeding from aircraft exhaust

          This is the exact thought that i had. I remember reading some analysis that said there was a significantly larger temperature range recorded due to the reduction in cloud cover over the US in the days following Sept 11th, as all the planes were grounded. Link []

          It makes sense that on average the increase in cloud would also reduce the solar radiation.Has anyone plotted, global flight hours of jet aircraft against year on year dimming effect? Sounds like a likely answer to m

    • Re:So instead (Score:4, Insightful)

      by Mr. Slippery ( 47854 ) < minus math_god> on Thursday December 18, 2003 @10:25AM (#7754206) Homepage
      of Global Warming, we have to worry about Global Cooling.

      Not necessarily. Venus, hottest planet in the system, is completely covered in clouds. They act as a blanket to keep heat in (cloudy nights are warmer).

    • by swordboy ( 472941 ) on Thursday December 18, 2003 @10:37AM (#7754336) Journal
      Every day, we get enough sunlight to power 27 years worth of the world's energy needs []. Now, I thought about the implications of that. Obviously, we couldn't absorb/store the entire amount, but if we could put a dent in it, we'd have some global cooling. That is what this article is about.

      On a similar note, the US could obtain all energy from the sun if it were to install a 200 mile square solar installation (assuming 15 percent efficiency... easily doable today). I say, put a dime of tax on each gallon of gas and use this money to subsidize solar generation - one of the only energy producers out there with net positive energy (more energy produced in the cell's lifetime than it takes to produce the cell itself). Hydro, wind and solar... I can't wait for the day.

      On yet another related note, I'm in the process of building a solar/NiMH PC. I'm simply going to use store-bought NiMH rechargables to store excess daytime solar input. It certainly won't be cost effective but it'll be pretty high on the geek factor.
      • by FJ ( 18034 ) on Thursday December 18, 2003 @11:15AM (#7754722)
        There is no such thing as a free lunch.

        Where do you want to dump the highly toxic chemicals that would be the result of the 200 square mile solar installation? Where are you going to put it that wouldn't make environmentalists, homeowners, or farmers go crazy and is still safe from natural disasters?

        Wind is nice and clean, but it takes a lot of windmills to generate enough power to replace a power plant. Windmill farms are regarded as many to be ugly so people don't want them around their houses.

        Hydro sounds like a great idea, but many people have a bias against hydrogen because of past mistakes with it. We can handle it much safer now, but it is still more dangerous than gasoline.

        Also remember that the bigger you make something, the more difficult is to maintain. Snow, ice, earthquakes, tornados, and hurricanes can cause havoc on large equipment.

        Everyone knows the nasty side effects of using oil & coal energy.

        Don't get me wrong, I (like you) am looking forward to the day when I can throw away all gasoline powered devices, but we are not quite there yet. Hopefully it will be very soon.
        • [hydrogen] ... is still more dangerous than gasoline.

          I don't believe this statement is factual. Source, please.

        • by js7a ( 579872 ) * < minus punct> on Thursday December 18, 2003 @04:08PM (#7757576) Homepage Journal
          Wind is nice and clean, but it takes a lot of windmills to generate enough power to replace a power plant. Windmill farms are regarded as many to be ugly so people don't want them around their houses.

          Actually, the entire electricity requirements of the United States could be served by wind turbines with a combined land-use footprint of only 14,000 acres, including enough grid redundancy to provide 99.5% uptime through long grid transmission to areas experiencing calm winds. (The remaining 0.5% backup could be hydro or whatever.) That area is only twice the size of the Stanford campus, and as large as the amount of Oak forest that California loses each year.

          Some people consider turbines ugly at first glance, but more people want wind turbines in their neighborhood than want mercury-spewing coal smokestacks in their state.

          Wind power is the fastest growning renewable industry [] and is expected to be the dominant form of power production in less than 30 years [].

          Please see the Windpower FAQ [] for more information.

      • by Skim123 ( 3322 )
        It's been a while since high school physics, but isn't there a loss in the energy when transmitting electricty over long distances? That is, it wouldn't be plausible to build one huge-ass power plant in the middle of the US and have it serve as a power source for all of North America. If this assumption is correct then it's quite clear why we can't just appropriate the bottom half of New Mexico for one giant solar cell.
    • Re:So instead (Score:4, Informative)

      by cev ( 572524 ) on Thursday December 18, 2003 @12:32PM (#7755502)

      I AM an optical scientist, so I'll fill in a few gaps that are not covered in the article, and are often misrepresented. The phenomenology of propagation through the atmosphere is very different for longwave infrared, visible (& shortwave infrared), and ultraviolet (UV). That is why it is possible to have global warming with decreasing sunlight, and increasing UV.

      NOTE: when I say 'atmosphere,' I mean the part where most of the air is, i.e., just the stratosphere and troposphere. Don't be a snot about the "exosphere".

      1. Most of the energy reaching the earth from the sun is in the visible and near IR wavelengths. The atmosphere is nearly transparent to these wavelengths, so a lot of the sun's energy reaches the surface of the earth. Scattering from particulates (e.g. pollution, volcanic material, water particles, etc.) is the primary loss mechanism for sunlight. Most of these particulates are close to the ground, or well-distributed through the atmosphere. Therefore, nearly all of the sunlight gets close to the earth.

      2. Dangerously short wavelengths (cosmic rays, x-rays, gamma rays, hard UV) are scattered and absorbed at the cusp of earth's atmosphere. Almost none reaches even the lower atmosphere. Soft UV is predominantly absorbed by ozone. The atmosphere itself scatters short wavelengths very well (thus, blue sky).

      3. Excepting a few 'windows', the atmosphere is opaque to longwave infrared light. Earth emits long-wave IR light due to its low temperature. Longwave IR light from is absorbed in the atmosphere, preventing the earth from cooling itself. This is the 'greenhouse effect.' Since the atmosphere is so opaque to longwave-IR, the greenhouse 'panes' are pretty much at the edge of the atmosphere.

      4. The article presents research which raises the possiblity that increased pollution (possibly) is causing more solar energy to be absorbed in the lower atmosphere. Global warming is still possible since the lower atmposphere is still 'inside' the greenhouse, so the extra abosrbed energy is still contributing to heating. UV light is being absorbed by the particulates as well, but not enough to offset the damage done to the ozone layer.

      6. Do I believe the article? A little bit. The main point is that a previously crazy idea was corroberated very well by a second, independent measurement (evaporation). Two improper experiments are much less likely than one. Still, 10% seems pretty big.


  • Well I guess this means the prices of sunglasses will go up so invest in raybans now

  • by JPelorat ( 5320 )
    Since agricultural output has already multipled and skyrocketed over the years thanks to technology and IPM, this isn't necessarily a burning crisis..
  • by Malc ( 1751 ) on Thursday December 18, 2003 @10:07AM (#7754001)
    This makes me wonder about the drive towards a hydrogen-powered economy. All that water vapour coming out of car exhaust pipes, etc. Probably a better form of pollution from a health perspective, but will it also result in limiting sun light or producing clouds that trap heat?
    • by djh101010 ( 656795 ) on Thursday December 18, 2003 @10:14AM (#7754076) Homepage Journal
      How do you expect you'll be getting your hydrogen, exactly? Hydrogen is a _storage mechanism_, not a fuel. You have to put energy into the chemical reaction to get Hydrogen - it's not something you can mine. The same (or more) emissions would be created in a hydrogen-fueled infrastructure, just that that CO2 would be produced at the hydrogen production facility, rather than at the point of use.
      • You're right. I was mixing thoughts on local and global effects. Globally things could be worse. Locally though, hydrogen powered cars will reduce some of the concentrated pollution in our cities and around big roads. I would really appreciate not having to breathe the crap from cars that we currently get whenever I step out the door. It won't mitigate our dependence on foreign oil though, nor this debate on global warming and pollution in general. I think we still need to move towards energy conserva
      • What? Sure, we can mine for Hydrogen. We will mine the public treasuries for subsidies to make lots and lots of Hydrogen. Within 30 years, the rurals will be slaving away to afford the land taxes to pay for the urbanites having H-powered cars so they can zippidy doo dah down their brightly lit streets (which will have to be brightly lit, due to less sunlight, you dig?).
      • by fireboy1919 ( 257783 ) <(gro.llehseerf) (ta) (pytsur)> on Thursday December 18, 2003 @12:27PM (#7755446) Homepage Journal
        You're right about the storage mechanism thing, but wrong about the emissions thing.

        Automobiles are one of the more dirty ways of converting fossil fuel energy into usable energy, specifically because really good filters, and very high temperature combustion are not desirable (for both portability and usefulness reasons).

        However, if this is done at a plant, these issues go away. The burning process will be much cleaner.
    • but will it also result in limiting sun light or producing clouds that trap heat?

      I would think that lots of clouds would block sunlight and make the earth cooler. Isn't that the idea behind nuclear winter?
      • I think I read a long time ago that the different types of clouds affect the atmosphere in different ways. Some reflect/block the sunlight causing cooling, but some trap heat beneath them.
  • Air polution (Score:2, Insightful)

    by liquidpele ( 663430 )

    "The few experts who have studied the effect believe it's down to air pollution."

    As if the acid rain and cancer wasn't enough...
    Can we PLEASE move to a friendly energy source now?
    Not trying to go all political, but looks like we are stuck with fossel fuels [] for a while...
  • by Anonymous Coward on Thursday December 18, 2003 @10:08AM (#7754005)
    I always felt that the world was a brighter place when I was a kid, now I have proof!
  • Full Text (Score:5, Informative)

    by jhouserizer ( 616566 ) * on Thursday December 18, 2003 @10:10AM (#7754026) Homepage
    Goodbye sunshine

    Each year less light reaches the surface of the Earth. No one is sure what's causing 'global dimming' - or what it means for the future. In fact most scientists have never heard of it. By David Adam

    Thursday December 18, 2003
    The Guardian

    In 1985, a geography researcher called Atsumu Ohmura at the Swiss Federal Institute of Technology got the shock of his life. As part of his studies into climate and atmospheric radiation, Ohmura was checking levels of sunlight recorded around Europe when he made an astonishing discovery. It was too dark. Compared to similar measurements recorded by his predecessors in the 1960s, Ohmura's results suggested that levels of solar radiation striking the Earth's surface had declined by more than 10% in three decades. Sunshine, it seemed, was on the way out.

    The finding went against all scientific thinking. By the mid-80s there was undeniable evidence that our planet was getting hotter, so the idea of reduced solar radiation - the Earth's only external source of heat - just didn't fit. And a massive 10% shift in only 30 years? Ohmura himself had a hard time accepting it. "I was shocked. The difference was so big that I just could not believe it," he says. Neither could anyone else. When Ohmura eventually published his discovery in 1989 the science world was distinctly unimpressed. "It was ignored," he says.

    It turns out that Ohmura was the first to document a dramatic effect that scientists are now calling "global dimming". Records show that over the past 50 years the average amount of sunlight reaching the ground has gone down by almost 3% a decade. It's too small an effect to see with the naked eye, but it has implications for everything from climate change to solar power and even the future sustainability of plant photosynthesis. In fact, global dimming seems to be so important that you're probably wondering why you've never heard of it before. Well don't worry, you're in good company. Many climate experts haven't heard of it either, the media has not picked up on it, and it doesn't even appear in the reports of the Intergovernmental Panel on Climate Change (IPCC).

    "It's an extraordinary thing that for some reason this hasn't penetrated even into the thinking of the people looking at global climate change," says Graham Farquhar, a climate scientist at the Australian National University in Canberra. "It's actually quite a big deal and I think you'll see a lot more people referring to it."

    That's not to say that the effect has gone unnoticed. Although Ohmura was the first to report global dimming, he wasn't alone. In fact, the scientific record now shows several other research papers published during the 1990s on the subject, all finding that light levels were falling significantly. Among them they reported that sunshine in Ireland was on the wane, that both the Arctic and the Antarctic were getting darker and that light in Japan, the supposed land of the rising sun, was actually falling. Most startling of all was the discovery that levels of solar radiation reaching parts of the former Soviet Union had gone down almost 20% between 1960 and 1987.

    The problem is that most of the climate scientists who saw the reports simply didn't believe them. "It's an uncomfortable one," says Gerald Stanhill, who published many of these early papers and coined the phrase global dimming. "The first reaction has always been that the effect is much too big, I don't believe it and if it's true then why has nobody reported it before."

    That began to change in 2001, when Stanhill and his colleague Shabtai Cohen at the Volcani Centre in Bet Dagan, Israel collected all the available evidence together and proved that, on average, records showed that the amount of solar radiation reaching the Earth's surface had gone down by between 0.23 and 0.32% each year from 1958 to 1992.

    This forced more scientists to sit up and take notice, though some still refused to accept the change was real, and instead blamed it on inacc

  • by plumby ( 179557 ) on Thursday December 18, 2003 @10:12AM (#7754053)
    So the pollution that pumps out of power stations is making it too dark to switch to solar power. How convenient.
  • by Shivetya ( 243324 ) on Thursday December 18, 2003 @10:13AM (#7754071) Homepage Journal
    There is no accurate model of the environment. Worse, its obvious a few of these guys have a serious attitude problem.

    What it comes down to is, whose policies are most in favor with the scientific community will get results from that community supporting their position. Screw the fact they don't have all the facts, it doesn't prevent either camp from making claims.

    Its Global Warming this pas 15 years, before then it was Global Cooling.

    Environmentalism is much more about ideaology than realism.
    • by Savage-Rabbit ( 308260 ) on Thursday December 18, 2003 @11:11AM (#7754680)
      Environmentalism is much more about ideaology than realism.

      From my point of view it is about:
      • Leaving my house and not having to be greeted by the nausiating smell of burnt gasoline.
      • Living in a place where everytning is not covered with thin black layer of soot from car exhausts.
      • Being able to see the mountain on the other side of the bay that is currently obscured by a thick curtain of smog.
      • Being able to eat the fish I catch in one of the local rivers without risking my health.
      • .....the list goes on.

      Those seem pretty practical demands to me.
      • by amcguinn ( 549297 ) on Thursday December 18, 2003 @11:44AM (#7755054) Homepage Journal
        Indeed. That is what environmentalism used to be about. Real, obvious problems that you could point to and do something about.

        Unfortunately, real environmental problems are usually created locally*. Fixing them means taking the economic hit locally -- losing factory jobs in your own city, reducing the fertilizer-driven crop yield on your own farm, having a smaller engine in your own car, whatever.

        It's much better to deal with global environmental issues, which are, by definition, somebody else's fault. "It's not me, it's those darned Amazonian loggers! I can't do anything by myself, the world's governments need to get together and make everyone do things differently."

        [* important exception: rivers. Rivers carry and in some cases even concentrate pollution from large distances upstream]

  • by fuck_this_shit ( 727749 ) on Thursday December 18, 2003 @10:14AM (#7754074)
    We can thus conclude that we know nothing. Weather patterns haven't been recorded for a long enough time to make any valid long time prediction of such things as global warming or freezing. Once they manage to consistently predict tomorrows weather successfully they may go onwards and claim they have a clue how the weather will be 100 years from now. For those screaming "Kyoto!" etc: yes, reducing pollution is good and should be something to strive for for every somewhat intelligent human being, but I wouldn't draw a conclusion about global warming from what was presented yet.
  • weird (Score:5, Interesting)

    by ikoleverhate ( 607286 ) on Thursday December 18, 2003 @10:14AM (#7754081)
    Quite weird - there was an elderly farmer saying much the same thing this morning on my bus to work.

    I'm pretty sure he wasn't a guardian reader, it's just something he'd noticed over the years.

    At the time, I thought he was talking crazy talk...
    • Re:weird (Score:3, Interesting)

      by arivanov ( 12034 )
      I have noticed that as well. In the early eighties I needed to use suncream in the summer and had a few cases of vicious sunburns when I did not. Nowdays I no longer need it unless I go as far south as the tropics. Another thing I have noticed is that unfortunately all these studies do not give you a distribution across the visible, near UV and near IR spectrum. They are a sum of all. If there was distribution data the actual reason would have been much easier to pinpoint. For example a flat decrease/incr
      • Re:weird (Score:3, Interesting)

        by lobsterGun ( 415085 )
        You're probably just spending less time in the sun and not remembering it. One of the lines in the article mentioned that the sunny times are just as bright and warm as before; It 's the cloudy times that are darker. ...or I could be remembering it wrong.
    • Re:weird (Score:4, Funny)

      by LaCosaNostradamus ( 630659 ) <[LaCosaNostradamus] [at] []> on Thursday December 18, 2003 @12:04PM (#7755257) Journal
      Eldery farmers are just kooks. Everyone know that. (They even believe in owning firearms .. I mean, that's just crazy!) They don't have degrees, and all they do is mess around in the dirt (which can just get some wetbacks to do anyway). What the hell do they know? After all, it's not like the Human animal can watch something change for decades and come to a conclusion on the basis of that. Nope, not at all.

      It's better overall to have scientists shaking their heads, saying things like "if it's this significant, then it would have been reported before". After all, it's not possible to have something reported the first time. Nope, not at all. These scientist guys really know their stuff.
  • by G4from128k ( 686170 ) on Thursday December 18, 2003 @10:16AM (#7754112)
    I suspect that some of this global dimming is due to pollution from sulfates (coal), jet contrails, and dust from wind-borne erosion. Sulfate and particulate pollution provides nice nucleation sites for cloud formation. These pollution-created artificial clouds probably reduce global warming (the article mentions this effect and a correlated decrease in cloudiness and increase in temperatures in the 1990s).

    The scary part comes if we reduce these forms of pollution, reduce cloudiness, and thus accelerate global warming. Whether we like it or not, humanity is changing the climate -- as attractive as it seems, preservation is impossible. At this point, it might be better to think about climate engineering -- deciding how we want to change the climate rather than holding on to the false hope that we can avoid changing the climate.
    • by HeghmoH ( 13204 ) on Thursday December 18, 2003 @10:40AM (#7754365) Homepage Journal
      The thing people always seem to forget is that climate stasis is impossible even if humans had never existed. This stuff changes with or without us. We may or may not be affecting the process, but no matter what, we can't make it stay the way it is forever.
    • by Damek ( 515688 ) <adam&damek,org> on Thursday December 18, 2003 @10:51AM (#7754477) Homepage
      I'm no climate scientist, or climate engineer, but it seems to me that dark |= cold. A greenhouse can be dark but hot. The gasses keep in the heat, yet keep out the light. Venus springs to mind.

      So I wouldn't see this as a benefit. I would think reducing pollution would increase light reaching the ground, but also help decrease how much heat is retained in the atmosphere.

      I'm probably wrong, I suppose.
      • I'm no climate scientist, or climate engineer, but it seems to me that dark |= cold. A greenhouse can be dark but hot. The gasses keep in the heat, yet keep out the light. Venus springs to mind.

        Scientists have been debating this one quite a bit -- whether cloud's reflection of the sun light creates more cooling than the cloud's night-time heat-trapping abilities. The suspension of airtravel around 9-11 gave scientists a chance to study this []. They found that the absence of contrails created pronounced h
    • by Waffle Iron ( 339739 ) on Thursday December 18, 2003 @11:32AM (#7754896)
      These pollution-created artificial clouds probably reduce global warming (the article mentions this effect and a correlated decrease in cloudiness and increase in temperatures in the 1990s).

      The Venusians apparently made the same assumption about their climate, unfortunately.

  • I wonder if this is similar to a greenhouse. This would explain both the dimming AND the global warming. The glass from a greenhouse (comparable to the atmospheric gasses) undoubtably blocks some of the sunlight getting to the plants/surface. Yet we all know it's a bit warmer in the greenhouse than in the surrounding area outside.

    If this analogy is correct, we really do have a lot to fear. Not only will we continue to have global warming but it seems as if the humidity level of the planet may rise too. O
  • It's an extraordinary thing that for some reason this hasn't penetrated even into the thinking of the people looking at global climate change," says Graham Farquhar, a climate scientist at the Australian National University in Canberra.

    So the bigger problem here is that it's getting increasingly harder for information to penetrate the thick skulls of humans. Looks to me like the number of thickheads is growing at a rate faster than 3% a decade, more like 300%

  • "Lifes short and hard, like a body building elf, so save the planet and kill yourself."

    or perhaps a better quote from Futurama.

    "I'm glad global warming never happened. It did, but nuclear winter canceled it out."

  • Animatrix (Score:4, Funny)

    by boatboy ( 549643 ) on Thursday December 18, 2003 @10:31AM (#7754272) Homepage
    Didn't you people see Animatrix? We HAD to do this to prevent the robot takeover, but it will only cause them to come after us for batteries.
  • Rock On!!! (Score:5, Funny)

    by fuzzybunny ( 112938 ) on Thursday December 18, 2003 @10:37AM (#7754332) Homepage Journal
    So, if I get this right, global dimming and global warming are compatible, possibly complementary phenomena. This would mean that the world is getting warmer & darker.

    Now, I'm not a scientist, but this sort of implies to me that things will get more humid as well. So, we're setting up for living in a big ole' sauna. So, let's look at the ups and downs:

    Good: We'll all have great skin for starts.

    Bad: Lots of very fat men walking around in flip-flops with small towels around their waists.

    Good: Girls will wear less clothing to cope with the heat & humidity--we'll have a population of nice-skinned chicks dressed like the love-slaves from planet Triton. Misquoting Mary Carey []: "Global warming? Never heard of it, but I guess we'll all have to wear less". Woo!

    Bad: Killer hangovers, massive ring around the collar.
    • Re:Rock On!!! (Score:5, Interesting)

      by pavon ( 30274 ) on Thursday December 18, 2003 @11:17AM (#7754740)
      Good: We'll all have great skin for starts.

      Actually, the article mentioned that it was visable and infrared light that was being blocked by an excess of clouds, not ultraviolet. Add to this the fact that our magnetic feild is becoming less polarized, in the process of flipping. As it does so there will be a bunch of little poles (places where the magnetic feild points into the earth not parrallel to it), guiding in additional radiation (and aroras, yay!). So if anything we will have more problems with bad skin not less.

      Also, as the earth has warmed we have seen an the wet places getting more precipitation and the dry places getting less. And the article said the dimming was not constant, just that we have had more clouds and the clouds obviously block light, but the deserts, with no precipitation will have fewer clouds and thus less dimming.

      My prediction: the world will be divided into radsuit wearing deserts desert dwellers, and mutant frog men, who live in swamps.
  • by occamboy ( 583175 ) on Thursday December 18, 2003 @10:39AM (#7754350)
    Some datapoints:

    1. In general, studies of this type are very difficult to do. One has to take into account:

    • the non-continuity of the measurements (they're not measuring everywhere, they are probably tending to measure near cities; cities cause definite local effects over time, but they are only a small percentage of Earth's surface area.
    • astonishingly few "scientists" actually understand how to use instrumentation. (Yeah, flame me - but it's true - I've done a lot of teaching and mentoring in this area). One of the problems of our age is that we all have access to sophisticated equipment, but few actually know what the results mean.
    2. It occurs to me that if the Earth's atmosphere were soaking up all of that energy, astronemers (one group that actually does know how to use instrumentation) would have noticed spectral changes years ago. But we haven't heard from them. (They could be part of a vast right-wing conspiracy to prop up the Bush and Cheney crew, I suppose, and are just not telling us.)

    3. I haven't done the calculations (has anybody?) but it also occurs to me that if Earth's atmosphere were soaking up all of that energy, there'd be some SERIOUS global warming occuring.

    4. In the article, the "discoverer" of our newest Earth-dooming catastrophe seems to indicate that he was amazed to have found this issue in the mid-80's when "there was undeniable evidence that our planet was getting hotter". As some of us will recall, the dominant paradigm in the mid-80's was global cooling. Global cooling in the '80s was as obvious and well-proven as global warming is today. And, actually, diminishing sunlight reaching the Earth would be consistent with global warming (see point 3).

    • Some counterpoints:

      2) Astronomers tools have been improving and changing alot over the time period in question, and as a result their measurements may not be consistant enough going back for them to compare and notice the trend, especially if they aren't looking for it.

      3) It's not necessarily just absorbed by the atmosphere, it could be reflected back into space by increased cloud cover.

      4) In the long run it could be consistant with either warming or cooling, depending on the mechanism that is reducing t
    • by pavon ( 30274 ) on Thursday December 18, 2003 @11:26AM (#7754829)
      3. I haven't done the calculations (has anybody?) but it also occurs to me that if Earth's atmosphere were soaking up all of that energy, there'd be some SERIOUS global warming occuring.

      IANAAP*, IAAIC**. But why would energy being soaked up by the atmosphere lead to a warmer planet than being soaked up by the ground which then heats the atmosphere? If anything it would just change the temperature gradient, not the mean temperature, making the surface temperature colder, no?

      * I am not an atmospheric physicist
      **I am an ignorant clod
      • The premise of nuclear winter is that the atmosphere absorbs all incoming solar radiation. The surface and the atmosphre then reach a radiative equilibrium through long wave emission. The equilibrium temperature of the surface is then the same as the planet's (as a whole) measured emission temperature from space. That is, 255 K. Average surface temp today is ~288 K. Increase atmospheric absorbption leads to decreased surface temps.
  • by mengel ( 13619 ) <`mengel' `at' `'> on Thursday December 18, 2003 @10:50AM (#7754456) Homepage Journal
    ... this [] article which pointed out that in 2001 from Sept 11-14 when all the airplanes were grounded, there was a measurable increase in Diurnal Temperature Range (i.e. how much the temperature changes day to night).

    So I blame jet airplane contrails.

  • by LarsWestergren ( 9033 ) on Thursday December 18, 2003 @11:00AM (#7754547) Homepage Journal
    "This new evidence proves global warming is bunk because now we know the scientists don't know everything."

    To me this makes just as much sense as rejecting biology as soon as scientists discover a new species. "See! The proves the bible was right!"

  • Not enough data (Score:5, Interesting)

    by jason0000042 ( 656126 ) on Thursday December 18, 2003 @11:07AM (#7754632) Homepage
    The scientists making these observations are trying to make conclusions based on about four decades worth of research. It seems probable to me that global atmospheric trends take millennia to unfold. From the 60's till now probably accounts for a couple of data points out of the hundred or more needed to actually spot a trend.

    Also, it seems that the assumption has been made that the sun produces constant output. I don't think we can make this assumption. The sun, as a system, is way bigger than our atmosphere. Until we have thousands of years worth of data, observed from outside the atmosphere, we can't prove that solar radiation is a constant. In fact, since solar flares temporarily increase solar output, you could postulate that thousand year trends in flare frequency and magnitude could affect the overall output of the sun.

    So, while global dimming may or may not affect us in the short term (on the scale of centuries) and pollution is still bad (again very long term effects are unrecorded, but it's obviously very bad in the short term (again measured in centuries) and it is ugly), I'm still not all that concerned that the world is going to ice over or boil away any time soon.

    • Re:Not enough data (Score:3, Informative)

      by barakn ( 641218 )
      Until we have thousands of years worth of data, observed from outside the atmosphere, we can't prove that solar radiation is a constant.

      It's not constant [], and so it only took several decades to prove it.

  • by e_lehman ( 143896 ) on Thursday December 18, 2003 @11:09AM (#7754654)

    The important point here is: we are altering the planetary system, but can not predict the effects.

    There is no doubt that we are changing the planetary system. If nothing else, CO2 concentrations are rising dramatically and human activity is definitely the culprit. And global temperatures are definitely rising []. Humans may or may not be the culprit, but a back-of-the-envelope calculation suggests that more CO2 should cause higher temps.

    The problem is that we can't predict the effects of these changes. It isn't like there's a global thermostat that we can turn up or down a half-degree by altering our industrial output. Rather, it is like throwing random chemicals into a bowl in a closed room, hoping you don't create toxic fumes. You might, you might not, but you don't know one way or the other, and you can't get out in any case.

    I spent several months looking into climate models and concluded that they're complete bunk. We can't predict the weather a week out, but people use the very same techniques to "predict" the climate a century out. Consider this: if you believe in a human activity-climate link, then in order to predict climate, you have to predict human activity. So predicting the behavior of the entire world economy is just one small source of the uncertainty in these models! They're garbage! Computer climate models just create a false sense of predictability about climate change.

    So this leaves us in a scary place. Here we are on earth. If we screw it up, we have nowhere else to go. We're making changes, but we don't know the effects. Since we don't understand the planetary system, we can't necessarily undo the effects. It's like remodeling an aircraft in flight.

  • by richone ( 21384 ) <rich@robot t h o u g h t s .com> on Thursday December 18, 2003 @11:13AM (#7754699) Homepage
    If we make it easier for the stupid people to survive, then of course Global Dimming will occur.
  • by chrysrobyn ( 106763 ) * on Thursday December 18, 2003 @12:04PM (#7755261)
    The few experts who have studied the effect believe it's down to air pollution. Tiny particles of soot or chemical compounds like sulphates reflect sunlight and they also promote the formation of bigger, longer lasting clouds. "The cloudy times are getting darker," says Cohen, at the Volcani Centre. "If it's cloudy then it's darker, but when it's sunny things haven't changed much."

    Please note here, much of this 10% is being reflected. There are people in this thread pointing out how untrue the observations must be because if 10% of the sun's energy was being absorbed by the atmosphere, the Earth would be getting a heck of a lot warmer than it is. Instead, the Earth should be getting 10% brigher from the moon or anywhere else in space. Particulates are reflecting and clouds are forming (which look very bright to me when I fly over them).

    I've been wondering about this. Would global warming end up creating enough clouds to reflect enough energy from the sun that it balances itself out after a few decades? Or will global warming cause an imbalance in the sun's reflected energy after a few decades that causes a swing on the cold side? How much does the CO2 green house effect compare to the particulate / cloud reflector effect?

  • by MacGod ( 320762 ) on Thursday December 18, 2003 @12:08PM (#7755293)

    I wonder if this will have any sort of noticeable effect on Seasonal Affective Disorder []. It has been shown that people feel more depressed with less exposure to the sun (this disorder is especially common in winter).

    It's funny, everyone talks about how people seem sadder and grumpier "these days". I wonder if there could be an actual link to this "global dimming".

  • by md65536 ( 670240 ) on Thursday December 18, 2003 @02:41PM (#7756710)
    Some of the quotes in the article indicate some pretty narrow thinking.

    First, less light == cooling down? "If that was the case then we'd all be freezing to death."
    There isn't less radiation coming from the sun, just less reaching the earth's surface ("there has been a general increase in overall solar radiation over the past 150 years"). This means it's probably being absorbed in the atmosphere, probably being converted to heat. By preventing that sunlight from being converted to non-heat energy (photosynthesis, evaporation), this might be heating up the atmosphere even more. I don't know where this heat goes, but it *might* be possible that less surface light means increased global warming. I guess the real questions regarding surface light and temperature is: How does a decrease in surface light affect the amount of energy that escapes the earth?, and Are we storing energy and remaining cool, or letting more energy be converted to heat?

    Second, "I don't think that aerosols by themselves would be able to produce this amount of global dimming." Aerosols "by themselves" might not filter that much light, but pollution does lead to "bigger, longer lasting clouds." It sounds like the "global dimming" just means less direct sunlight, not necessarily dimmer direct sunlight.

  • by meehawl ( 73285 ) <meehawl,spam&gmail,com> on Thursday December 18, 2003 @04:25PM (#7757750) Homepage Journal
    It's interesting to note that Earth's closest twin planet in terms of position and size is Venus, where a runaway Greenhouse Effect keeps surface temperatures around Venusian a toasty 480C (894F) but the entire planet is mired in a perpetual twilight gloom (verified by the Russian landers []) due to the extraordinarily thick atmosphere (around 9000 kPa or around 90 times Earth's atmospheric pressure). Venus's oceans long ago boiled away in this runaway Greenhouse Effect []. The oceanographic runaway Greenhouse Effect begins to occur over large bodies of water at around 27C (80F) []. Even ignoring current human-directed climate change, the increasing solar output of the Sun as it moves along a typical Main Sequence stellar evolutionary path [] means that sooner or later the Earth's oceans will also vaporise and temperatures soar quickly to Venusian levels. Strange days indeed lie ahead of us...

Any sufficiently advanced bug is indistinguishable from a feature. -- Rich Kulawiec