Comments 1 to 7:

1. Swayseeker at 00:58 AM on 3 February, 2019

   Regarding your "forcings and feedaback" section, with polar air cooling down large areas of the USA there is a huge net gain in radiation heat transfer to cold surfaces. The cold surfaces are radiating far less and, if the strength of solar energy is the same, then the overall radiation gain by these cold surfaces can be 50% higher (say they gain 200 W/m^2 at 20 deg C, then they could be gaining 300W/m^2 at 0 deg C). Earth would lose its highest percentage of heat via the 8 to 14 micron atmospheric window with surface temperatures of 79 deg C. At 0 deg C we are losing the battle when it comes to overall radiation heat transfer (huge overall gain).

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2. nigelj at 05:20 AM on 3 February, 2019

   "At 0 deg C we are losing the battle when it comes to overall radiation heat transfer (huge overall gain)."

   I don't see this. Only a few places are experiencing unusually cold temperatures right now. On the whole the earth is warming and winters are becoming milder so there would be no enhanced global level heat gain from solar energy. Or maybe I have missinterpreted the comment. Don't claim any expertise in it.

   I think you get enhanced solar heat gain more from decreased albedo as the arctic melts, glaciers retreat, more water vapour absorbing solar energy directly, etc and this is a big part of the projected warming.

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3. blaisct at 04:32 AM on 4 February, 2019

   As this is your first post, Skeptical Science respectfully reminds you to please follow our comments policy. Thank You!

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4. blaisct at 04:34 AM on 4 February, 2019

   I may be off base on my logic – please respond. Let me throw another law in to the works: Beer- Lambert (Absorption of light in a substance is a product of the distance, concentration, and absorption coefficient). Using published CO2 absorption coefficient of 20.2 m^2/mole (at 15um) the distance at which 99%+ of this wave length is absorbed at 400ppm CO2 is 16m. If the concentration is doubled (800ppm) the 99% distance lessens to about 8m. Since the energy (temperature in a fixed volume) is proportional to the light absorbed the air below 8m would be hotter in the 800ppm air. But this effect would only last as long as the air did not mix. But it is a gas and it will mix. Since the energy absorbed is the same at 400ppm or 800ppm the temperature of the mixed gas will be the same. The temperature (energy) comes from the radiation not the gas. The other 2 wave lengths of CO2 have slightly different coefficients but will result in the same mixed effect.
   For any gas in the atmosphere there is a concentration at a specific wave length where all the light is absorbed before it escapes from the atmosphere. Gases with concentration above this escape concentration will not absorb more light (energy) if their concentration is increased (saturated gas). Gases with concentration below this escape concentration will absorb more light (up to the saturated concentration). CO2 and water are examples of saturated gases. Methane and SO2 most likely are unsaturated. Therefore CO2 and water cannot be any part of the observed gw. They are just good greenhouse gases that absorb all their wave length of light in the lower atmosphere. Only a change in the light they can absorb will cause a temperature change. Albedo can make the light they can absorb change.
   A simple look at albedo’s contribution to gw: Using IPCC’s correlation of global temperature rise of 0.5’C/watt/m^2. The entire temperature rise from 1870 to present is 0.8’C, the IPCC says this is equivalent to 1.6 watt/m^2. Using solar radiation reaching the earth of 960 watt/m^2. Doing a simple proportion shows that only a 0.17% change in total earths albedo since 1870 would be needed to account for all the temperature change (about 0.7% if just land mass albedo). On an annual bases we would need a detection method that could see 0.005%/year change in albedo. What’s the possibility that man has added enough roads, roof tops, parking lots, and burned enough rain forests to account for a 0.7% change since 1870? Statistical correlation show about a 2’C higher temperature in urban measurements since 1900. Albedo is a powerful variable in climate change. It is what causes all our weather, evaporates water and moves almost all weather systems for west to east.

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5. nigelj at 06:23 AM on 4 February, 2019

   blaisct @4

   With respect your understanding of the principles isn't correct. Therefore whether the logic is right or wrong is irrelevant.

   The Beer Lambert Law is the linear relationship between absorbance and concentration of an "absorbing species". Not all gases absorb equally. Gases like oxygen molecule only absorb UV and break down in the very upper atmosphere above 80kms, and lower down its CO2 which absorbs long wave  energy, and this is causing global warming near the surface which is what is relevant to us.

   eesc.columbia.edu/courses/ees/climate/lectures/radiation_hays/

   Shortwave radiation from the sun heats surface features. It explains some warming over the early part of last century, but not enough to set in motion some feedback effect causing hugely reduced albedo.

   Regarding human caused changes in albedo since 1900. This doesn't explain global warming either. Urbanisation reduces albedo, but less than 1% of the world is urbanised. Deforestation increases albedo! So things essentially cancel out. Refer article below for a fuller review of the albedo issues:

   www.skepticalscience.com/earth-albedo-effect.htm

   Therefore greenhouse warming is the prime cause of global warming since the 1980's, and this in turn leads to reduced albedo in terms of reduced ice cover, and so some warming from SWR.

   You say: "Albedo is a powerful variable in climate change. It is what causes all our weather, evaporates water and moves almost all weather systems for west to east."

   I don't think so. I have only done some university geography, so not a climate scientist, but I was taught weather was caused by redistribution of heat from equator to poles etcetera, water evaporated if it was above zero degrees so is just basically due to the sun or greenhouse changes, and the flow of weather systems west to east was the coriolis effect and pressue differences. I guess the textbooks are all wrong and you are right (sarc). Or was your comment deliberate satire?

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6. MA Rodger at 07:20 AM on 4 February, 2019

   blaisct @4,
   You present a strange argument.
   I think your molecular cross-section of CO2 is far too low for 15 microns, your photon path-length too long, and it is not so simple as this because of line boradening at higher pressures.
   That aside, the photon path length will indeed halve with a doubling of CO2 concentration (and ignoring that temperature is not fully defined by radiative effects), there will be a temperature gradient mechanism (warming the upper atmosphere) due to CO2 at the lower warmer atmosphere being able to shoot more photons (transmit more energy) up than the cooler higher atmospher cane shoot back down. But thus mechanism will be balanced by convection to maintain the lapse rate. Mixing is very minor (as is convection) in the atmosphere outside major storms.
   The energy absorbed will rise with a doubling of CO2 as will the ability to shoot away photons. The temperature will rise as the population of photon-not-shot-away will be higher, adding energy to the air about and this balanced by increasing photon shooting in all directions - the extra absorption of photons under double CO2 has then to be balanced by increased temperature to allow these extra photons to be shot away.
   The "other 2 wavelengths of CO2" (presumably wave-bands) are not major IR absorbers within today's atmosphere.
   The ability to shoot photons into space is dependent on the concentration in the atmosphere-above allowing gaps to exist. Any increase in CO2 concentrations will close these gaps so increase absorption, increasing the height at which photons can escape. This height-rise means lower temperatures at which photons are shot into space (this while the point of escape is still within the troposphere) and so being cooler, less photons will be shot into space at that wavelength, reducing this global energy flux. This is the major mechanism of CO2 warming across the 15 micron waveband. The higher the concentrations of CO2, the shorter the photon path length and the denser the absorbing events and the higher the escape altitude.
   Given you seem to them proceed assuming "CO2 and water cannot be any part of the observed gw" which is simply wrong, I don't think it woud be helpful to point out any further mistaken logic.

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7. Art Vandelay at 17:26 PM on 4 February, 2019

   nigelj@5, a bit OT, but just coming out of another record breaking January here in eastern Australia, it seems to be largely driven by a lack of cloud cover over the tropical north of the continent. Clouds are obviously a component of global albedo, but regardless of whether global albedo is increasing or decreasing it's possble that there are long term trends with regional specificity.      

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