global dimming and warming

Warming and Climate Change: causes, consequences, analysis ... Debate on CO2 and other greenhouse gas.
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loop
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by loop » 01/02/08, 23:22

Bonsoir

I think we must relativize the influence of clouds, at least those of low levels

Natural cloud cover has always existed and is the consequence of the evaporation of water
I do not think we can mix the effect and the cause
Everything is a story of balance
To simplify: strong heat gives strong evaporation thus cloud cover which will tend to cool the atmosphere and therefore less evaporation etc .....

On the other hand, since we are talking about obscuration, it is a human influence, which is not neutral because it breaks the equilibrium described above, just like the warming linked to the greenhouse effect.

Here again the observation shows that globally, the blue sky becomes rare and it is not neutral because the formed screen is located at the top of the atmosphere, unlike the low layer clouds which absorb at the lower level

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Leo Maximus
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by Leo Maximus » 02/02/08, 11:01

loop wrote:Bonsoir
I think we must relativize the influence of clouds, at least those of low levels
Natural cloud cover has always existed and is the consequence of the evaporation of water
I do not think we can mix the effect and the cause
Everything is a story of balance
To simplify: strong heat gives strong evaporation thus cloud cover which will tend to cool the atmosphere and therefore less evaporation etc .....
On the other hand, since we are talking about obscuration, it is a human influence, which is not neutral because it breaks the equilibrium described above, just like the warming linked to the greenhouse effect.
Here again the observation shows that globally, the blue sky becomes rare and it is not neutral because the formed screen is located at the top of the atmosphere, unlike the low layer clouds which absorb at the lower level
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And volcanic eruptions play no role then? I thought earth observation satellites had shown the opposite.
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Remundo
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by Remundo » 02/02/08, 11:14

Hi Looping,

The difference is that there is cloud and cloud ...

A volcanic cloud carries low reflective dust with high absorbency at almost all wavelengths. Soot particles, black, behave almost like a black body: isotropic asborption followed by isotropic re-emission.

A cloud of water is more reflective and absorbs only certain wavelengths in the infrared re-emitted by the earth.

In short, radiative balances are very complex, with closures and feedbacks that we do not really know how to estimate the intensity, or even the mechanisms ...

One thing is clear however, the burning of fossil fuels contributes to global warming by 2 effects:
- CO2 emission which is a greenhouse gas
- soot / dust modifying the atmospheric absorption, and tending to increase it. This phenomenon can be very local (volcanic eruption, polluted city ...), but not globally at the scale of the Earth, although if we continue to dirty ...

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Cuicui
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by Cuicui » 27/11/08, 00:31

If it continues, our solar collectors will eventually be ineffective ... But this reduces global warming. Is there a relationship with contrails-chemtrails?
http://www.dailymotion.com/related/x350 ... art-1_news
http://www.dailymotion.com/related/x351 ... art-2_news
http://www.dailymotion.com/related/x34x ... art-3_news
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