This link demonstrates that the no feedback radiative sensitivity (i.e. no clouds!) for CO2 is 1.2 K/2xCO2.

He furthermore demonstrates in the link you give that the feedback factor is approximately 1, which implies no significant water vapour amplification and no cloud, latent heat or convection reduction.

You also musn't compare partial pressures of greenhouse gases directly. You must compare the spectroscopic infrared absorption: 300 ppm CO2 absorbs more infrared than 20 promille H2O (64% RH)

http://www.cactus2000.de/uk/unit/masshum.shtml

 well yes, but I don't have the book. It's similar to "the answer is in the library"

Please copy the definition of absorption absorbance and absorptivity, (because in my definition eg absorptivity is a molar property) , or explain what's wrong with the wiki definition of the Lambert-Beer law, because this law is the key to the debate.

As long as we don't even agree on the scientific definitions, a debate is fruitless.

When radiation is incident on the earth's surface, some fraction is reflected and the remainder is absorbed. The fraction absorbed we call the absorptivity while the fraction reflected is the reflectivity.

Transmission spectroscopy terminology used by chemists can be different. For myself absorptivity is short for molar absorptivity which is the α term in Beer's law A = α l c

A = absorbance = log₁₀ (I₀/I_l)

l = path length

c = concentration of the absorbing species

α = absorption coefficient or molar absorptivity or molar extinction coefficient

I₀ = initial light intensity

I_l = light intensity at l

Transmittance, T, is I_l/I_o

Absorption in spectroscopy is the conversion of the energy of radiation to heat or chemical energy.

The measured molar absorption coefficient is a function primarily of wavelength and spectrometer resolution. The shape of an absorption line of a molecular gas can be affected by pressure (pressure broadening) and temperature (doppler broadening) so the molar absorption coefficient over a short enough wavelength range (small compared to the line width) could and does change with pressure and temperature.

Kirchhoff's law defines emissivity as equal to absorptivity for a given wavelength and viewing angle. Kirchhoff's law only applies when the condition of Local Thermodynamic Equilibrium (LTE) is met. Meaning that molecules exchange energy by collision much more frequently than by interaction with the radiation field. Kirchhoff's law doesn't apply at very low pressure (very high altitude) where the collision frequency is low

Madmartigan, My number, is 1.3 K for doubling of CO2 (290 to 580 ppmv) and my source is Nur Shaviv.

Hans, Madmartigan is Nasif. Why the name change? I didn't recognize the writing style either.

Jan,
According to Grant Petty (Op. Cit. ,pp 98,99) , for real objects surface absorptivity is a function of wavelength and angle of incidence.

In general a and r depend on the wavelength λ. A surface that is highly reflective at one wavelength (r ~ 1) may be highly absorbing at another (r ~ 0). For example, grass and other vegetation appears green because it reflects green, yellow, and blue wavelengths more strongly than red or orange....

In addition, both of these quantities usually depend on the direction Ω [don't have the right character, it should have a ^ on top. It's the unit vector representing the direction of propagation.] = (θ,φ) of the incident radiation. For example, in Chapter 4 we saw that the reflectivity (in the visible band) of a smooth water surface varies from a rather small value of 2% at normal incidence (θ = 0) to nearly 100% at grazing angles (θ → 90^o).

Of course, some surfaces don't show much change over broad ranges of wavelength and angle of incidence.

I already discovered that

But this doesn't apply to a gas, or does it?

hans
But this doesn't apply to a gas, or does it?

indeed, but the wavelenght is 15 micron.