[ExI] Diminishing influence of increasing carbon dioxide on temperature

[Mirco Romanato]

Il 11/08/2014 15:02, Anders Sandberg ha scritto:
> spike<spike66 at att.net> , 10/8/2014 11:35 PM:
>
>     I need to dig around in my green notebooks and see if I can find
>     those calcs; I think it was from about 6 to 8 yrs ago.  At the time
>     I looked at the negative feedback balancing the increased
>     absorption: the radiation to space using the Stefan-Boltzmann
>     equation.  I concluded that the reason CO2 has never caused a
>     runaway greenhouse effect is that it cannot.  Even if CO2 retains
>     **all** the energy in its absorption band, that T^4 term still
>     overpowers everything else.
>
>
> I think this is right; it is the water vapor feedback that is needed
> for a runaway greenhouse.
>
> Raymond T. Pierrehumbert's excellent "Principles of Planetary Climate"
> has a nice treatment of the Ingersoll-Kobayashi limit (basically, with
> enough water vapor the stable fixed point disappears). I think he
> discussed a "pure" CO2 greenhouse too, but in that case there is no
> sudden jump to overheating.
>
> In any case, the reason there has not been any overheating so far might
> have been that Earth in the past was closer to the outer range of the
> life zone than we previously believed. Although the combined
> geological-biological-climatological system can be rather unpredictable;
> see some of the papers at http://www.pik-potsdam.de/~bloh/evol/

Did anyone took note of the Methane Clathrate effect on climate?
Higher temperature melt more ice, sea water rise, pressure on the bottom 
of ocean increase and the quantity of Methane Clathrate increase (it 
increase for increasing pressure or lowering temperature) and the 
methane in the atmosphere decrease decreasing the greenhouse effect.

Increasing water vapor increase the greenhouse effect but increase cloud 
light reflection before it reach Earth surface.

Now, if the real problem is increasing water vapor, what should we do?
Reduce Carbon emissions?

Mirco