[ExI] Greenhouse Gas
atymes at gmail.com
Thu May 9 04:53:38 UTC 2013
The total amount of heat coming in & going out
dwarfs the total amount blocked by CO2. In the
blanket analogy, imagine if each blanket was
incredibly thin, say 1/100th or less of an
ordinary blanket. Doubling the blankets, moth
eaten or not, will make a substantial difference.
Further, the bed underneath slightly changes
color in places in response to the temperature.
E.g., white ice melts into darker, more
absorptive things. Feedback effects like this,
especially when energy normally distributed
across the entire Earth gets localized (such
as into a tornado), account for much of the
On Wed, May 8, 2013 at 9:42 PM, Kelly Anderson <kellycoinguy at gmail.com>wrote:
> Could someone please comment on this analysis? It seems to make sense to
> me, and that kind of worries me. I keep thinking this is settled to some
> extent in my head.... I want to believe science is not totally screwed over
> by politics, I want to believe...
> The misnamed “greenhouse” effect of greenhouse gasses like CO2 is based on
> the fact that they are not truly colorless. They have a “tint,” though we
> can’t see it, because it’s in a part of the light spectrum that our eyes
> don’t detect. GHGs are transparent in the visible part of the light
> spectrum, but they absorb (block) parts of the IR spectrum.
> Adding such gasses to the atmosphere has a warming effect on the lower
> atmosphere, because the light arriving at the earth from the sun is much
> “bluer” (shorter average wavelength) than the light emitted from the earth.
> Because the earth is relatively cool, the light emitted from the earth is
> mostly IR. So anything in the atmosphere that blocks IR but is transparent
> to visible and UV will have a warming effect, because it lets in most of
> the arriving solar radiation (that warms the earth), but blocks a much
> larger percentage of the departing radiation (that cools the earth).
> Even though CO2 levels are measured in parts-per-million, there’s
> nevertheless already so much CO2 in the atmosphere that it blocks nearly
> all of the IR that it can possibly block. So adding more CO2 doesn’t have
> much effect on temperature. For CO2′s main absorption bands, we’re way, way
> past the CO2 levels at which the IR is all absorbed. Only for very narrow
> ranges of wavelengths at the fringes of those absorption bands, where CO2
> is a very weak absorber, can adding more CO2 appreciably increase the
> amount of IR blocked.
> However, adding even a small amount of a different GHG (such as one of the
> CFCs or HCFCs) can have a much larger warming effect, by blocking a part of
> the IR spectrum for which the atmosphere would otherwise be transparent.
> That’s why you may read that CFCs like Freon-12 are thousands of times more
> potent as GHGs than CO2. It’s not that there’s anything fundamentally
> special about Freon-12, it’s just that there’s so few Freon-12 molecules in
> the atmosphere that some of their absorption bands aren’t already blocked.
> Here’s an analogy. Consider moth-eaten blankets to be like GHGs, and
> different positions one the blankets correspond to different parts of the
> IR spectrum. The blankets have big holes in some places, but nice, dense
> wool fabric in others.
> Different patterns of holes in the blankets are like different GHGs. They
> pass some parts of the IR spectrum, and block others. So “CO2″ blankets
> have one pattern of holes, “CH4″ blankets have a different pattern of
> holes, “CFC-12″ blankets have yet another pattern of holes, etc.
> Now, envision an obsessively compulsive neat-freak piling on moth-eaten
> blankets to try to keep warm in a chilly night. He exactly straightens and
> lines up each blanket on the bed.
> If he piles on a dozen identical “CO2″ blankets, with the holes all lining
> up exactly, he won’t be much warmer than if he had only one or two “CO2″
> blankets. But if he adds a “CH4″ blanket, with many of its moth-holes in
> different places, then he’ll be a lot warmer, because some of the CO2
> blanket’s holes will be blocked by the CH4 blanket, and vice-versa. And if
> he adds a “CFC-12″ blanket, with some of its holes in different places than
> the holes in the CO2 and CH4 blankets, he’ll be warmer yet.
> Right now, we’ve got about 10 or 20 CO2 blankets piled on. Adding another
> 5 or 10 or 20 CO2 blankets will keep us a tiny bit warmer at the frayed
> edges of the holes, but it won’t make near as much difference as adding
> some other kind of blanket.
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