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Wednesday, March 26, 2014

Question of the day at WUWT: Why doesn't CO2 stay near the ground?

Sou | 3:04 AM Go to the first of 16 comments. Add a comment


Seen at wattsupwiththat, a comment by cnxtim, who says:
March 25, 2014 at 6:07 am
I am still waiting to find out hoe CO2 generated at ground level by the burning of fossil fuels, makes it’s way to the upper atmosphere to join other molecules of CO2? , Or was I asleep in class and somehow missed that very important first step in the ‘science’ of AGW?
surely there is a pro CAGW teacher out there who could enlighten me?


I'd say cnxtim has been asleep for a long time.  Ferdinand Engelbeen was the only person to give an answer and he says it quite well. Although I'll add that most CO2 doesn't make it to the upper atmosphere.  Most of it stays in the troposphere. Here is what Ferdinand wrote:
March 25, 2014 at 7:26 am
Not that difficult: if sand grains can be transported for thousands of km from the Gobi desert in Mongolia to Arizona, while sand is about 1,000 times more heavy than air, it is no problem for air to transport CO2 which is only slightly heavier a lot of times around the earth. Further, upwards air flows are available at a lot of places and certainly in the tropics by thunderstorms and other ascending and descending air flows.
It takes some time to mix the releases and uptakes of CO2 into the bulk of the atmosphere: a few days to a few weeks for the same altitude and latitude, a few weeks to a few months for different altitudes and latitudes, and 6 months to 2 years for the transfer from the NH to the SH, as only 10% per year of air is exchanged between the hemispheres.
But in general, CO2 levels are within 2% of full scale from sealevel to 20 km height and beyond. Only near ground on land, there are a lot of local sources and sinks which makes that you can measure any level of CO2, depending of the proximity to these sources and sinks and wind/mixing speed.

One other thing I'll add is that gas molecules move.  They don't just move downwards, they move sideways and up.  And they move quickly.  Here is an extract from an education website, which is probably the class that cnxtim dozed off in.
In gases the particles move rapidly in all directions, frequently colliding with each other and the side of the container. With an increase in temperature, the particles gain kinetic energy and move faster. The actual average speed of the particles depends on their mass as well as the temperature – heavier particles move more slowly than lighter ones at the same temperature. The oxygen and nitrogen molecules in air at normal room temperature are moving rapidly at between 300 to 400 metres per second. 
Unlike collisions between macroscopic objects, collisions between particles are perfectly elastic with no loss of kinetic energy. This is very different to most other collisions where some kinetic energy is transformed into other forms such as heat and sound. It is the perfectly elastic nature of the collisions that enables the gas particles to continue rebounding after each collision with no loss of speed. Particles are still subject to gravity and hit the bottom of a container with greater force than the top, thus giving gases weight. If the vertical motion of gas molecules did not slow under gravity, the atmosphere would have long since escaped from the Earth.

16 comments :

  1. If I could only count the number of times I've had to argue with climate deniers over this simple point.

    I usually mention that maybe they should avoid the coasts and mountain valleys because they are clearly uninhabitable due to heavy concentrations of CO2 that have settled there.

    ReplyDelete
  2. And how about those clouds? Ice crystals, large assemblies of water molecules, surely this should drop like a stone?!

    ReplyDelete
  3. Didn't Wegman make this gaff in front of Congress? What a tool...

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    Replies
    1. Forgive me, but even for Wegman that sounds far-fetched.

      Delete
    2. Sometimes reality is more bizarre than fantasy.
      Try pp.10-12 of the PDF linked in my other comment, and then p.8 to see where all those bad arguments appear. The Wegman Report was wrong on science and statistics. See also FOIA Facts 1 which brought all this up to date ... and got worse.

      Delete
    3. I have an image of the future : a face falling into a palm ... forever.

      Thank you for that pointer, John Mashey, and for all your forensic efforts. Deeply appreciated.

      Delete
  4. Rattus: yes:
    Strange Scholarship,, pp.61-62.
    'DR. WEGMAN. Again, it is the connection between carbon dioxide and temperature increase. Now, Mr. Inslee pointed out that he thinks there is a physical explanation based on a blanket of carbon dioxide in the reflection. Carbon dioxide is heavier than air. Where it sits in the atmospheric profile, I don't know. I am not an atmospheric scientist to know that but presumably if the atmospheric--if the carbon dioxide is close to the surface of the Earth, it is not reflecting a lot of infrared back.'

    A week or so later, he tried to back out of that p..62.


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    Replies
    1. I am not an atmospheric scientist but doesn't the world gliding altitude record stand at something like 45,000 feet? Last time I checked, gliders were heavier than CO2 molecules.

      Delete
  5. The question is not that stupid, what is stupid is to think that climate scientists have overlooked something this obvious and aggressively ask: "surely there is a pro CAGW teacher out there who could enlighten me?"

    The description of the education website is for a gas in a container. Then diffusion is the mixing force. In the atmosphere turbulence is much stronger as diffusion.

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    Replies
    1. Victor, your statement presupposes that turbulences are sufficiently understood to make such a definitive assertion.

      Sorry, I couldn't help it. I was channelling Eric for a moment. It just goes to show how silly the arguments that deniers make. They seem to think that just because they don't understand the physical processes of the planet, that no one else does. CO2 is well mixed all the way up to 100km, and for someone like Wegman not to know that, is disgraceful. He did say that he wasn't a atmospheric scientist, so how on earth could he debunk the work of Mann. It's no wonder that he copied and pasted so much for his 'paper'

      It seems that deniers are getting stupider, and then to top it off, to try and make themselves look smarter, they troll blogs with the most stupid and inane comments, hoping that their stupidity will somehow be transferred to other people.

      Delete
    2. I agree that no question is stupid - if it is asked with a genuine spirit of enquiry and desire to understand that is admirable. As you say it is the aggressive nature of the enquiry that is the give away that there is not a real desire to understand.

      It is a bit odd to only ask for a "pro CAGW teacher" for enlightenment. (Is there such a creature?). I think that is an unintentional tell that you cannot look for sensible answers from the denier community.

      Delete
    3. "it is the aggressive nature of the enquiry that is the give away that there is not a real desire to understand."

      that, plus not listening to the answers

      Delete
  6. Heh, I commented on this in the last month or so (was it here or and Prof Bunny's?) and reminisced about the Tim Curtin days:

    http://scienceblogs.com/deltoid/2008/03/22/remember-eg-becks-dodgy/comment-page-2/#comments

    It's worth wading through the posts to see just what a numpty Curtin was...

    The thing is, if anyone actually wanted to educate themselves before opening their mouths to change feet they could easily find pages such as these:

    http://www.newton.dep.anl.gov/askasci/chem03/chem03325.htm

    http://physics.stackexchange.com/questions/34733/why-does-air-remain-a-mixture

    that give some general background, and just as easily find some research on exactly this subject:

    www.caves.org/pub/journal/PDF/v71/cave-71-01-100.pdf‎

    lss.fnal.gov/archive/2005/conf/fermilab-conf-05-635-ad.pdf

    And there's no excuse for not knowing about it - the matter was researched almost a hundred years ago:

    www.jbc.org/content/73/2/379.full.pdf‎

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  7. If the atmosphere did stratify according to molecular mass, there would be a tiny thin layer of CO2 at the bottom (I'm ignoring some trace gases) so there would be no trees because there would be nothing for them to use in photosynthesis at their height. Above the CO2 layer would be a thicker layer of argon, then a more substantial layer of oxygen in which animals would have to live, along with fungi. Above the oxygen layer is the thickest layer, nitrogen, and finally water vapour on top.

    Luckily reality isn't like that. And some of these people feel competent to comment on complex science and they can't master basics.

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  8. Remember meteorologist Joe Bastardi? He also got it wrong.

    Joe Bastardi "Implications of co2 specific gravity heavier than air (1.5 to 1) it cant possibly cause trapping hot spot at 400mb in GHE" facebook, Jan 13, 2012

    Joe Bastardi: "CO2 can not cause global warming. I'll tell you why. It doesn't mix well with the atmosphere, for one. For two, its specific gravity is 1 1/2 times that of the rest of the atmosphere. It heats and cools much quicker. It's radiative processes are much different. So it cannot - literally cannot cause global warming." Said on Fox Business and quoted by ThinkiProgress, also on March 11, 2012. "Bastardi doubles down on his anti-science BS in the comments."

    ReplyDelete
  9. The mixing ratio of tetrafluoromethane, CF4, (even heavier than CO2) is altitude-independent through the troposphere and stratosphere. This has been well known for a generation. This figure from NOAA is worth showing to the incognoscenti.

    http://www.esrl.noaa.gov/csd/assessments/ozone/1998/faq1.html

    ReplyDelete

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