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Science

BBC on Global Dimming 470

Posted by michael from the what-me-worry dept.
linoleo writes "The BBC reports that the amount of solar energy reaching the Earth's surface has declined significantly between the 1950s and the 1990s, apparently due to particulate air pollution. Scientists are worried that this global dimming may be disrupting the pattern of the world's rainfall. Most alarmingly, it may have led us to greatly underestimate the greenhouse effect: with particulate pollution being brought under control, a global temperature rise of 10 degrees Celsius by 2100 could be on the cards, rendering many parts of the world uninhabitable." The lengthy transcript of the show is available.
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BBC on Global Dimming More

BBC on Global Dimming

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  • less is more (Score:2, Insightful)

    by Gherald ( 682277 )
    Let me get this straight... we are getting less sunlight, but the world is getting hotter?

    • Re:less is more (Score:3, Insightful)

      by SithGod ( 810139 )
      Actually, what they're saying is that since we are finally getting pollution under control, the increased amount of sunlight will compound with the current greenhouse effect. At least that's how I read it
    • Let me get this straight... we are getting less sunlight, but the world is getting hotter?

      they fear its getting less rainfall too...

    • Re:less is more (Score:5, Informative)

      by CmdrGravy ( 645153 ) on Friday January 14, 2005 @11:02AM (#11361475) Homepage
      Yes, essentially the program says that we are getting less sunlight and the world is getting hotter.

      They say we are getting less sunlight thanks the visible pollution in the atmosphere which encourages cloud formation in a fashion which reflects more sunlight than clouds formed around natural pollutants such as pollen.

      We are making big steps to clean up the visible pollution and therefore bringing the amount of sunlight back to normal levels.

      However given that the world is still warming up despite the cooling effect of this reduction of sunlight they are supposing this must mean that global warming is in fact a lot more powerful than they first thought since we can still detect noticable warming despite a reduction in sunlight.

      As we clean up more and more of our visible pollution without cleaning up our CO2 pollution we may face a much bigger temperature increase than we were expecting.

      The program was fairly sensastionalist and towards the end went through some highly speculative "we are all going to die" scenarios. I would have liked them to concetrate more on the evidence they have for global dimming and maybe some contrary evidence or any doubts the scientific community may have about the results of the scientists they did show.

    • Re:less is more (Score:3, Interesting)

      by Mr_Dyqik ( 156524 )
      The sunlight is hitting the earth, just not reaching the surface. This has the effect of heating the upper atmosphere, and reducing the power at the earth's surface.

      You may now run some atmospheric modelling code to work out what the hell this will do to the climate.

      An immediate conclusion made in the article is that this effect is masking the current rate of climate change due to CO2, so that as we clean up the atmosphere due to reduced particulate emissions, the greenhouse effect will get worse, even i
    • Yes. The reason is that the amount of energy we're getting from the Sun is the same (more or less).

      According to this model, the percentage of sunlight that actually reaches the surface is getting smaller, while the increasing rest is heating the atmosphere (due to heat buildup on dust particles). That's why the model predicts an increase in temperature.
    • Well, yes, because between us and Sun there is that thing called athmosphere that we shit into and that takes the hit (and the heat).

  • Good for the UK! (Score:5, Funny)

    by caluml ( 551744 ) <slashdot@spamgoe ... minus herbivore> on Friday January 14, 2005 @10:55AM (#11361360) Homepage
    Great - the UK might be a nice place to live by then! You can keep your Med coasts in France, and Spain - arrid deserts, they'll be in 100 years. Invest in Dorset [imagesofdorset.org.uk], I say :)
    • The UK? I WINTER in the UK when I can. Try living in North Dakota. We go to Scotland in March just to get a bit of sunshine and warmth. Bring on the warming trend! It is -20F outside right now, and it gets colder some days.
      • I WINTER in the UK when I can

        Oh you poor deluded soul.

        pay the extra and go somewhere with a lower population density at a closer-to-the-equator kinda latitide. jeez.
        • It was a joke. You have jokes in the UK, right?

          I know you probably don't know where North Dakota is, but just look at map of the US, find the middle of the country, and then just go up to the top. A little bit to the left of those big fresh water lakes we have.

          That area of the planet (Minnesota/North Dakota/South Dakota) actually has the second most variable temperatures in the whole world, behind Sibera.
      • The UK? I WINTER in the UK when I can. Try living in North Dakota. We go to Scotland in March just to get a bit of sunshine and warmth.

        Ha ha ha..... bwa ha ha ha! (Falls off chair laughing)

        This has *got* to be a joke. I've lived in Scotland all of my life, and I still think the weather from October to April or so sucks.

        And temperature isn't everything; even though the coldest days in winter tend to be those with clear blue skies (no insulation), there is also no rain at those times, no permeating d
    • As an inhabitant of coastal UK (Blackpool, Lancs) it may or may not get warmer but I'm a little concerned about the predicted rise in sea levels. Dorset may be fine, well, some of it, but you might want to think twice before investing in Norfolk, Suffolk, Lincolnshire, large chunks of Essex, London......
      • Rising sea levels are a problem for poor countries. Just half the funding to the NHS (which is the most wasteful organisation in the history of humanity) and we've got over fifty billion pounds per annum to spend on sea defences. Fifty billion a year will pay for a lot of sea walls, especially if we concentrate them around areas with a high population density.
    • Great - the UK might be a nice place to live by then!

      ... but what will happen to the indigenous people of the British Isles? I heard they combust if exposed to sunlight for more than 4 hours.
      • ... but what will happen to the indigenous people of the British Isles?

        Most of them they moved to Wales and Scotland when the French invaded to avoid being slaugtered.

        • Hey, those weren't the idiginous population. They were the Celtic invaders from eastern Europe.
        • ...Anglo Saxons, not French (originally Danes).

          The Scots (originally Irish, but by now Scotch) were at this time inhabiting Ireland, having driven the Irish (Picts) out of Scotland; while the Picts (originally Scots) were now Irish...
    • I think they ended up concluding that once the greenland ice cap had melted and the methane deposits trapped under the oceans had been released that the UK would have a North African desert climate during the summer with huge dust storms and catastrophic rain and flooding during the winter.

      North Africa however would suffer a 10 degree increase in temperature and become totally unihabitable.

  • So as long as... (Score:4, Insightful)

    by Vardan ( 172720 ) on Friday January 14, 2005 @10:58AM (#11361413)
    we keep the level of particulate matter in the the atmosphere up, we don't have to worry about the greenhouse effect![/sarcasm]

    Really, this article jumps to far too many conclusions with far too little data.

    "...a global temperature rise of 10 degrees Celsius by 2100 could be on the cards."

    And with exactly the same certainty as this statement expresses, if I dance around in a circle every Thursday night, an average rainfall increase of 17 inches could be in the cards!

    • You should read the whole transcript (or watch the program), rather than pulling a sentence out of the summary and scoffing at it.

      Plenty of data was presented to support the primary conclusions in the program. In particular decades worth of solid measurements demonstrating the drop in insolation, and satellite data showing pretty convincingly that this drop is due to increased reflection of sunlight.

      The program was pointing out that this "global dimming" is a demonstrably real effect and needs to be studi

  • Fear Fear Fear (Score:5, Informative)

    by Dominatus ( 796241 ) on Friday January 14, 2005 @10:59AM (#11361422)
    Global temperature has risen, fallen, and risen since 1880, even though carbon dioxide levels have steadily risen. In fact, for 30 years between 1940 and 1970 the temperature dropped all that it had gained in the past 50 years. Overall in the past 120 years global temperature has risen 1 degree celsius.

    One brings into question the level of accuracy from third world countries in the early 1900's. When one looks at the average temperature in America it tells a different story. From 1880 to 1920 temperatures dropped 0.5 degrees celsius. From 1920 to 1934 temperatures rose 0.9 degree celsius. From 1934 to 1976 temperatures dropped 0.8 degrees celsius. From 1976 to present temperatures have risen 0.7 degrees celsius, for a net total of 0.3 degrees celsius in 124 years.

    • Re:Fear Fear Fear (Score:3, Insightful)

      by Twanfox ( 185252 )
      There are many factors that go into creating the temperature of the planet. Reflectivity of the atmosphere, distance to the sun, atmospheric composition, etc. The greenhouse effect from CO2 is predictable and provable. Just because we have had global temperatures fluxuating does not disprove that CO2 is an atmospheric insulator and traps solar energy. Unless this CO2 is being drawn back out of the atmosphere (by plantlife, by carbon deposition, water absorption, or whatever else it can do), continually ramp
    • From 1880 to 1920 temperatures dropped 0.5 degrees celsius. From 1920 to 1934 temperatures rose 0.9 degree celsius. From 1934 to 1976 temperatures dropped 0.8 degrees celsius. From 1976 to present temperatures have risen 0.7 degrees celsius, for a net total of 0.3 degrees celsius in 124 years

      Well, now perhaps we have an explanation for all this. During the cooling years, there could have been in increase in particulate pollution (e.g. 1880-1920, burning of more coal; 1934-1976 increased industrialisation)

      • Given the range of change, assuming his numbers are correct, that .3 degrees could be easily swallowed by another drop, etc. Depends on what part of the cycle we're in. Don't get me wrong, I believe that global warming is a problem. I don't think its the cataclysmic end of the world that its being portrayed as. At least not yet. Unfortunately, it takes sensationalism to get people to do anything.
      • The general trend in america is NOT upwards, it's flat. Had I been less generous and not started from 1880 I could make this statement:

        Since the 1930's there has been NO increase in temperature in America. None. In fact, it was hotter in the 1930's than it is now, though very slightly.
        • Oops, correction, I was looking at 4 year old data for that one. The temperature is *slightly* hotter now than it was in the 1930's, but not by much:

          http://www.giss.nasa.gov/data/update/gistemp/gra ph s/Fig.D.gif

          There's temperature in America since 1880.
      • Sorry for another post, but one more thing.

        http://www.csmonitor.com/2004/0318/csmimg/p17a.g if

        Those are temps in antartica for the past tons of years. As you can see, Our current phase is actually *less* hot than it "should" be if the trend were to continue the way it has been. And the temperature Goes up and down between 10 degrees celsius and people didn't perish :)

    • Re:Fear Fear Fear (Score:2, Informative)

      by matrem ( 806375 )
      Global temperature has risen from 1900 to 1940. Between 1940 and 1970 it did not rise or fall, from 1970 onwards it has risen. See this [uea.ac.uk] if you want to see it for yourself.

    • Re:Fear Fear Fear (Score:3, Insightful)

      by barawn ( 25691 )

      Global temperature has risen, fallen, and risen since 1880, even though carbon dioxide levels have steadily risen.

      There's no doubt that CO2 levels have risen. There's also no doubt that they're far above what they've ever been over thousands of years (ice core data).

      Who cares what the temperature data says? We know we can't arbitrarily raise the CO2 levels in the atmosphere ad infinitum. Putting off reducing CO2 emissions is just procrastination (and dangerous, for economic reasons, but ignoring that...
    • Why dont you stick a label to "Global-warming":
      "Global warmimg is a theory, not a fact."

      Instead of having people believe its all a fear monger game.
  • lets all screw up our environment.. we may as well speed it up .. start using more coal and gas based turn off all clean nuclear power stations (yes they are clean until the end product is required). and then we can go and increase the capacity of our engines 10 fold.. no worries.. lets all be selfish and not give a shit!!!..
    • Too true, y'all. accelerating global warming will bring for th'apocalypse, and therefore the second coming, and in its wake Jeeeezuz's 1000 year utopian reign on earth.

      Who am I channeling?

  • Earlier /. Global Dimming articles (Score:4, Informative)

    by GillBates0 ( 664202 ) on Friday January 14, 2005 @11:00AM (#11361443) Homepage Journal
    More on Global Dimming [slashdot.org] May 13

    Global Dimming [slashdot.org] Dec 18

    Hint to editors: I obtained the links by doing a Slashdot search for dimming [slashdot.org]. Also checked that a Google site:slashdot.org search [google.com] also turned up results.

  • Environmentalist Claims Sky Is Falling! (Score:2, Funny)

    by Anonymous Coward
    News at 11.

    Seriously folks, non-doomsday research doesn't get as much funding as doomsday research.

  • WooHoo! (Score:3, Funny)

    by Lumpy ( 12016 ) on Friday January 14, 2005 @11:00AM (#11361447) Homepage
    I knew buying all that land in the frozen north would pay off!

    all those people will be flocking to the tropical shores of wonderful Lake erie!

  • Output Increasing (Score:5, Interesting)

    by Wyatt Earp ( 1029 ) on Friday January 14, 2005 @11:01AM (#11361469)
    And at the same time the amount of energy put out by the Sun is increasing.
    http://www.space.com/scienceastronomy /sun_output_0 30320.html

    http://www.hypography.com/article.cfm?id=32945
  • With al the pollution, floods, drought, storms, global warming, global ice-age, asteroid impacts, spiders,... what is the safest place on earth to live?
    No serious, I live somewhere in western europe near the cost. But since I am only in my early 20's, I can still move somewhere else.
    So where would you move to, or how high above or below sea level would you move?
    All these fear mongering stories are nice and scary, but damit, provide them with a map with the affected areas.
    • I was thinking about Knoxville, Tennessee..USA. Downtown Knoxville is 936 feet above sea level, it is considered (by me) to be on the other side of the Appalachian Mountains, from the Atlantic. A drive from the Atlantic to Knoxville is around 10 hours and the area is littered with mountainous small caves. Plus there is a river that runs through the middle.

  • Always so negative (Score:3, Funny)

    by Inkieminstrel ( 812132 ) on Friday January 14, 2005 @11:03AM (#11361493) Homepage
    You guys are always so negative. With a global temperature rise of 10 degrees, think of all the places that would become inhabitable... like Canada.

  • The article wanders a bit: it starts by talking about the dramatic increase in particulate matter in the atmosphere, i.e. very small bits of carbon and ash given off as a result of combustion.

    But then the article ends with this:

    That means a temperature rise of 10 degrees Celsius by 2100 could be on the cards, giving the UK a climate like that of North Africa, and rendering many parts of the world uninhabitable.

    That is unless we act urgently to curb our emissions of greenhouse gases.

    That's a goo
    • The problem is that we are already rapidly cutting particulate emissions (as part of buring oil more cleanly than before, due to oil prices as much as environmentalism), so global dimming should ease soon. The greenhouse effect won't ease though (even clean burning butane releases CO2), so the temperature rises observed so far will accelerate, even if the atmospheric CO2 levels stay the same.
    • The premise is this:

      We have global dimming, caused by particulate pollution, the world is getting less light than it used to.
      Despite this, we have global warming, caused by greenhouse gases, the world is getting hotter.

      Therefore, if we clean up the particulate pollution without tackling the greenhouse gas problem, then the global warming could become more pronounced because of the increased sunlight reaching us.

      I didn't RTFA but I did WTFP (Watch the program).
  • ...you already think it's uninhabitable.
  • Global dimming is just one factor. You have the greenhouse gas- CO2, methane-; The sun changes its brightness output a tenth or two a percent in cycles; the earth's orbit varies a bit; weather and ocean currents change, and so on. The Cassandras see runaway warming or ice ages at every turn. Real scientists say to continue studying to better understand it.

  • Kent Brockman reporting (Score:4, Funny)

    by Kohath ( 38547 ) on Friday January 14, 2005 @11:07AM (#11361554)
    Kent: Hordes of panicky people seem to be evacuating the town for some unknown reason. Professor, without knowing precisely what the danger is, would you say it's time for our viewers to crack each other's heads open and feast on the goo inside?

    Professor: Mmm, yes I would, Kent.

    http://www.snpp.com/episodes/1F09.html
  • See the Slashdot story [slashdot.org] from 2003.
  • welcome our new global warming overlords.

    It's frickin cold up here in Canada during winter.

    A few more degrees, and the Champlain Sea might be reborn, and give me a nice beachfront property on the edge of the soon to be renamed "Ottawa Valley".
    • To all the fellow northerners who say "hi-ho!" I say this: it may be that way but I guess it is a tad more complicated than that. See - if you get a flu and lie in your bed with high temperature you don't heal it by taking an ultra-cold shower or walking outside in the snow in your shorts only. Earth nature is an amazingly balanced and complex thing and "one-step-forward" thinking may not work as we expect.
      • Earth nature is an amazingly balanced and complex thing

        Not supported by the evidence. If nature were so amazingly balanced, the planet would be a wasteland by now. Too many natural changes have occured in the past that would have wiped out all life on the planet.

        The conclusion warranted by the actual evidence is that the biosphere is extremely robust and adaptive.
  • So, actually, they are asking us to keep polluting, to keep global warming and global dimming balanced ?

    this sounds like a bad cartoon ... Two powers in delicate balance
  • So, who else read this and immediately considered the fact that this is the basic plot of Fallen Angels [baen.com] by Larry Niven, Jerry Pournelle & Michael Flynn? Pollution is actually holding the climate in a more "human friendly" mode, and the Earth enters a minimum - basically a short ice age - which all the eco-nuts thinks is a good thing, since it's "natural"... despite glaciers grinding away at major cities.

    Incidently, that link goes directly to the first chapter - it is one of Baen's first experiments wi

  • photographic memory (Score:4, Interesting)

    by Blitzenn ( 554788 ) on Friday January 14, 2005 @11:17AM (#11361689) Homepage Journal
    This would certainly explain something that has bothered me for some time. I am cursed with a memory that remembors images with clarity I wish I didn't have. I have noticed that images from my childhood, (admittedly decades old now), seem to be 'brighter' than those I have of recent times. It's not a 'hazy' difference as you would expect. It is that the images seem 'brighter' to me. If I revisit the same location, it's not the same, even on a bright sunny day.

    I know it probably seems ludicrous to most people. I don't talk about things like that normally, because people just dismiss you as nuts, but it's real to me. I am curious, are there any others out there with long term photo memories that exhibit the same thing as I see?
  • Can anyone explain why light causes more heating if it reaches the surface than if it's absorbed in the atmosphere? I would have thought that the energy released would be the same either way, so why would more light reaching the surface cause an increase in temperature?

    • descriptive nouns (Score:3, Informative)

      by zogger ( 617870 )
      depending on all the factors, more of the heat is lost to colder "space" in one situation as opposed to another. We get heat from three sources, internally from the planet itself, man made burning and normal large scale surface burning (lightning strikes to forest for example), and solar radiation. The atmosphere acts as an insulating blanket and keeps it more moderate than not, but it's not a *perfect* insulator, and tiny variables cause profound changes. In one situation with the increase in greenhouse ga
  • > with particulate pollution being brought under control, a global temperature rise of 10 degrees Celsius by 2100 could be on the cards, rendering many parts of the world uninhabitable

    So... so... the environmentally concerned scientists are saying...
    WE NEED MORE POLLUTION?!

    My head hurts.
  • Less sunlight is reaching the earth, yet the earth is going to get 18 degrees Fahrenheit hotter in the next 95 years?

  • global warming? No, global climate change.... (Score:5, Interesting)

    by iamnot ( 849732 ) on Friday January 14, 2005 @11:34AM (#11361924)
    As a student of global climate change (the warming part has long since been dropped), a few scientific facts need to be added.

    #1 - Global climate change means exactly that - it will get warmer in some places, colder in others. And while idyllic thoughts of long summers around Great Bear Lake might spark a real estate boom, there will be a few downsides to the change. Disease vectors love warm weather, which means that pesky malaria (so, caused by bad air after all!) will become a feature of northern summers.

    #2 - The problem of increased warming due to pollution reduction is well known. These are relatively large particles being talked about, the ones that reflect sunlight back out (like after a volcano) - this does not include the smaller particles that have a much larger "green house" effect. Thus as we reduce large particulate pollution, the speed of warming will indeed increase.

    #3 - The "wait and study it so we know what is happending" arguement. This arguement has many supporters, including those who love discount rates. The fact is, once a glacier begins to melt (ahem, Greenland), there will be no way to stop it. Mind you, it might take a few hundred to a few thousand years... so maybe 2k'ers get the last laugh?
  • a global temperature rise of 10 degrees Celsius by 2100 could be on the cards, rendering many parts of the world uninhabitable.

    and other parts prime for days at the beach! My property values in NJ are going to go up!!!

  • larger drops in solar output seem questionable (Score:4, Insightful)

    by khallow ( 566160 ) on Friday January 14, 2005 @12:09PM (#11362409)
    If there was really a global 22% drop in solar output even over so many years, I think we'd notice the drop in agricultural output. Many food plants (apparently, peppers and tomatoes [sciam.com]) are highly dependent on solar output to the point you would expect a proportional drop in agricultural output from those plants.

    IMHO even over 50 years, we should be able to spot trends of that order of magnitude in our food crops.

  • From "concerned" to "worried" (Score:3, Insightful)

    by TeachingMachines ( 519187 ) on Friday January 14, 2005 @03:01PM (#11365303) Homepage Journal
    At this point, whatever we did to curb our emissions, it would be too late. Ten thousand billion tons of methane, a greenhouse gas eight times stronger than carbon dioxide, would be released into the atmosphere. The Earth's climate would be spinning out of control, heading towards temperatures unseen in four billion years.

    This article is probably the one that will turn people from "concerned" to "worried." We are talking about making the planet uninhabitable. On any continent. It's amazing that people are talking about this as "pop science garbage." How comforting it is to take such a position, because otherwise you'd actually have to be worried about this issue.

  • NEWS FLASH (Score:4, Funny)

    by PriceIke ( 751512 ) on Friday January 14, 2005 @04:00PM (#11366079)

    BBC EXCLUSIVE: Scientists have acquired evidence that the Earth will be absorbed by the Sun in approximately 7.7 billion years.

    "No one will survive this catastrophe," claims experts. "All life on planet Earth will be extinguished. If we don't take action now, this atrocity will claim every living man, woman and child on this planet."

    Environmentalists are asking for trillions of dollars for research grants and book advances with which to shriek about the coming apocalypse.

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