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Science

The Sky Is Rising 42

Posted by michael from the look-out-above dept.
Makarand writes "The height of the tropopause, the boundary layer between the troposphere and stratosphere and the roof of the Earth's lower atmosphere, has risen by an average of around 650 feet globally over the last 22 years according to this article in the San Francisco Chronicle. Greenhouse gases trap infrared radiation and warm the troposphere. The resulting tropospheric expansion is moving the tropopause upward. Also, the ozone depleted stratosphere is losing its ability to absorb sunlight causing it to cool and contract pulling the tropopause upward."
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The Sky Is Rising More

The Sky Is Rising

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  • OMG, we'll all be exploded instead of smashed!
  • I can just imagine Chicken Little running around with a little yo-yo going "THE SKY IS RISING! THE SKY IS RISING!" :P
  • Wouldn't this also have an effect on hail, lightning and snow flakes? If these items are affected by travel within the storm, wouldn't a larger area of vertical travel cause hail to be more likely, lightning to be stronger (more convection space) and snow flakes to be larger?

    All our weather happens in the tropopause yes, but doesn't it extend down into the troposphere where it hits the earth making the troposphere that much larger?

    Also, if the tropopause is rising, does that mean the stratosphere is shrinking or rising? Is the whole atmosphere being pushed out? Is the jet stream rising with it?

    Suppose this could mean higher expenses for air carriers, as they would need to climb to higher altitudes to get to the calmer stratosphere?
    • I'm not sure as fare as lightning, however for hail, rain, and snow, because of the way physics works they reach their terminal velocity fairly quickly and therefore won't "speed up" by the time they reach the land.
      Snow shouldn't be larger because of the way clouds work and how at a certain developmental stage it will reach a weight that allows it to escape and fall.
      However as fair as the air carriers comment goes, I do agree with you, and I fear for the ever increasing airfare...
      it's time for amtrak to lower it's fares :)
    • All our weather happens in the tropopause yes,

      No.

      Is the whole atmosphere being pushed out?

      The outer atmosphere rises and falls in tune with the day night cycle and the 11 year solar cycle.

  • Of course (Score:4, Insightful)

    by SpaceLifeForm ( 228190 ) on Wednesday January 22, 2003 @09:47AM (#5134956)
    This is to be expected. Imagine the atmosphere as a balloon. If you heat it, it will expand. And not only that, but it's surface area will stretch and become thinner. Now imagine that the surface area of the balloon is the earth's ozone. There is only so much to spread around, and it becomes thinner and thinner. In the case of the balloon, it will pop of course, in the case of the atmosphere, it will re-organize itself in whatever state the laws of phsyics decide it should be organized. I.E, the ozone "hole". My point here is that the ozone "hole" can exist not just because of CFCs, but also because of Global Warming.

    • Re:Of course (Score:3, Insightful)

      by Alsee ( 515537 )
      it's surface area will stretch and become thinner.

      We are talking about something like a quarter-mile increase on a sphere with a radius of about 4000 miles. The "stretch factor" on the surface area and thickness is 0.0001.

      There are some interesting and complicated effects going on, but a thinning of the ozone layer due to stretching isn't one of them.

      -

      • Re:Of course (Score:3, Informative)

        by B.D.Mills ( 18626 )
        We are talking about something like a quarter-mile increase on a sphere with a radius of about 4000 miles. The "stretch factor" on the surface area and thickness is 0.0001.

        Your figures are incorrect because the earth isn't stretching along with the atmosphere.

        The approximate shape of the troposphere *isn't* a sphere. It's shape is more like a solid of revolution formed by a thin annulus being rotated about its centre. (I don't know the name of this shape. But think of what shape an eggshell is if there was no egg inside it.) The troposphere is about 15-20 miles thick so an increase in thickness of 650 feet is more like a 1% increase. That's still small, but bigger than you thought.
        • Your figures are incorrect...

          My figures are correct.

          You got a different answer because you what measured was something other than what I measured.

          I said "There are some interesting and complicated effects going on, but a thinning of the ozone layer due to stretching isn't one of them.

          You measured a 0.01 change in the troposphere, but the ozone layer is not in the troposphere. Any thinning of the ozone layer due to a stretching effect would be approximately 0.0001.

          -

    • Not so simple (Score:3, Informative)

      by siskbc ( 598067 )
      That's a good analogy, but the atmosphere is a good bit more complex than that. First, the atmosphere doesn't 'pop' like a baloon would - if anything it would keep getting thinner. Second, with more surface area where the ozone layer is shifted to, more ozone will be produced, which should counteract the effect.

      But ultimately, the ozone hole occurs at the south pole for two specific reasons: First, the poles get a lot less radiation that the rest of the earth, hence less ozone production there. Second, the air currents over antarctica serve to trap the CFC's and ozone there DURING WINTER, allowing the CFC's to devour the ozone without it being able to re-mix with the rest of the atmosphere.

      Note that this year the ozone hole actually shrank and split in half, due to a change in the weather patterns over antarctica. So I would be extremely hesitant to use a baloon analogy to explain the ozone hole - atmospheric chemistry is so hideously complicated.

  • oh the humanity! (Score:4, Funny)

    by mcmonkey ( 96054 ) on Wednesday January 22, 2003 @10:15AM (#5135157) Homepage
    "Greenhouse gases, including carbon dioxide from the burning of fossil fuels, trap infrared radiation, warming the atmosphere. Santer and his associates believe that as the warming accelerates, the troposphere expands, just as a balloon warms and expands when it drifts from a cool room into a warmer one. Tropospheric expansion nudges the tropopause upward."

    A more likely explanation, this is all a result of white people doing that "raise the roof" move.

  • Before everyone shouts global warming... (Score:3, Insightful)

    by Omkar ( 618823 ) on Wednesday January 22, 2003 @11:00AM (#5135546) Homepage Journal
    try to remember we're just coming out of a frickin' ice age. The earth's temperature fluctuates, and not necessarily because of humans.
    • It's been shown that at least some of the change is due to human activity, and we can't wave our hands and make that just go away.

    • The earth's temperature fluctuates, and not necessarily because of humans.
      People's heartrate fluctuates, and not necessarily because of caffeiene. However, if I just downed a triple espresso, and my pulse is now at 150bpm, it's a pretty good hypothesis that the drug is responsible, and common sense that if I don't want further increases I should cut back.
    • we're just coming out of a frickin' ice age

      Do you have a reference for that? Last I heard we were overdue for an ice age by some tens of thousands of years.

    • try to remember we're just coming out of a frickin' ice age.

      No, no, no... You got it wrong. We're just going into a new ice age. Global warming causes influx of excessive fresh water into the oceans (melting ice). Excessive fresh water in the Atlantic causes the Gulf stream to stop. With no Gulf stream to bring warmer waters to Europe, Europe freezes.

      I suggest practicing winter sports if you're living in Europe. My plan is to relocate somewhere further south. :-)
  • So this is why the clouds are red sometimes: It's the red shift on the light from the clouds, resulting from the expanding sky!

    And sometimes the sky is red because it reflects the light from the tomatina festival [latomatina.com].
    • So this is why the clouds are red sometimes: It's the red shift on the light from the clouds, resulting from the expanding sky!

      LMOA! Good one :)

      A velocity of 650 feet per 22 years gives redshift:
      Z = 1.00000000000000095.

      Note: Don't try to use a relativistic redshift formula unless you have special software. Even 128 bit floats will bomb. The velocity is just too close to zero.

      -
    • And sometimes the sky is red because it reflects the light from the tomatina festival.

      Getting a bit off topic here, but the underside of clouds can actually give a sign about what is underneath them. If you are on pack ice or snow covered land, look for clouds with a very dark, almost black, underside. You might find open water, snow-free land or forests in that direction.
      Regarding tomatia, the tomatoes might contribute to a reddish hue in the clouds above the city, but I doubt that they would make a measurable difference:-)
  • Hmm.. wonder how much effect this could have on satellites in low earth orbit.

    From what I've read they already experience enough drag from the extreme edge of the atmosphere that there orbit needs boosting every so often (eg. the ISS).

    Could this mean more boosts are needed? (decreasing the life of the satellite, or in the case of the ISS - making it more expensive to keep up there).

    Maybe the first time global warming has caused an effect outside of the planet. :)
  • Most of us have a rough idea what the troposphere and stratosphere are, but I missed the border crossing sign at the tropopause last plane trip I took.

    What is the definition by which they measure its height? The article doesn't say.

    • The tropopause is the boundary level, between the troposphere and stratosphere, at which temperature no longer falls as you rise in altitude.

      As you move beyond the tropopause, into the stratosphere, atmospheric temperature will rise because the stratosphere contains more ozone. Ozone absorbs a significant portion of the UV light from the sun, adding energy to warm the atmosphere. Because atmosphere at these altitudes is much less dense, it doesn't take nearly as much energy to make changes in temperature. Because temperature rises with altitude, the stratospheric air is stable, with little vertical mixing.
  • It's interesting. Back in the days when I was obsessed with Sim Earth, I remember watching carefully how mass extinctions started. They weren't caused by any immediate disaster like a comet impact or volcano. Most extinctions started when the oxygen level of the planet started diving just a little bit. That set in motion a feedback loop of some kind that drove the oxygen in the atmosphere to zero fairly quickly, leaving nothing alive but trees and some sea animals. It was a difficult process to recognize, and even harder to stop.
  • I don't mind a taller breathable atmosphere (will this ease the plight of those who go to high altitudes?) but skin cancer is no joke. I wonder if anybody's run the numbers on how much extra ozone is required to statistically eliminate one skin cancer case? Furthermore, how much would it cost to launch ozone generators (solar/fuel cell powered) into the stratosphere to just replenish the stuff.

    Now there would be a worthy effort for a green group to take up. Too bad the mostly seem to be to busy protesting to actually solve problems.
    • The pressure will remain the same (on average). The ideal gas law: PV=nRT. T going up causes V to go up, P remains the same (as it is related to the weight of the air column over the area where the pressure is being measured). So the breathable atmosphere won't be taller.

      The amount of energy needed to create enough ozone would make it prohibitively expensive. Luckily the offending ozone-destroying molecules have been largely phased out and the ozone layer will start to recover within our lifetime.

    • I might have jumped the gun. The pressure would remain the same at sea level but there would be a redistribution in atmosperic density vs. altitude. On a mountain, with some of the atmosphere having moved from below one's feet to over one's head, the pressure would be higher, but not enough to notice.
    • I wonder if anybody's run the numbers on how much extra ozone is required to statistically eliminate one skin cancer case?

      None... just takes people with common sense and SPF 30.

  • Increasing CO2 also causes stratospheric cooling! (Score:1, Informative)

    by Anonymous Coward
    The header is correct in stating that ozone depletion leads to stratospheric cooling (i.e., through less absorption of UV).


    However, the stratosphere also radiatively cools for enhanced CO2 levels.


    As described in the 'Scientific Assessment of Ozone Depletion: 1998' by the World Meteorological Organization, "an increase in greenhouse gas concentration enhances the thermal infrared emissivity of a layer in the stratosphere; hence, if the radiation absorbed by this layer remains fixed and other factors remain the same, then, to achieve equilibrium, the same amount of energy has to be emitted at a lower temperature and the layer cools."

  • What science is this based on? (Score:3, Informative)

    by twfry ( 266215 ) on Wednesday January 22, 2003 @01:47PM (#5136906)
    Also, the ozone depleted stratosphere is losing its ability to absorb sunlight causing it to cool and contract pulling the tropopause upward


    Um, the tempurature of the air above another layer of air does not contract or pull air below it up or down. The stratosphere's weight would be the same causing the same amount of force to be exerted on the tropopause. The tropopause's height is only effected by 1) its own temperature and 2) the compression force of whats above it.

  • Regardless of whatever conclusions are derived from weather calculations I believe they are fundamentally flawed. Based on past performances and predictions, we don't have a clue about what is going on.

    On a somewhat related matter, I used to date a Weather Chick and she was as unpredictable as the weather but she had piss-flaps as big as saddlebags!

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