Thread by @ncdave4life

@Rocky35418823 @fischerfischy @Anvndarnamn5 @GordonDHG_clim8 @Faktantarkast10 @Michael_D_Crow @JimBowersclimb @SniemN @heinsenberger @ChrisBBacon3 @Willard1951 @TheDisproof @CraigM350 @DenisDaly @ubique60 @Climatehope2 @Jaisans @CDMarshall7 @Data79504085 @glinch72 @Ceist8 @EthonRaptor @Hji45519156 @ammocrypta @RMcgillss @ShaMikaWhoSeeks @paligap17 @JustThi30117912 @AristotleMrs @S_D_Mannix @BointonGiles @MaggieL @Willy1000 @Mark_A_Lunn @AuroriaTwittori @3GHtweets @RushhourP @MartinJBern @gstrandberg1 @ItsTheAtmospher @Jakegsm @EricWil06256732 @DTGvmd @wille99 @PaulDFarrar @KCTaz @Valja46Zhark5 @drochir_thonnuk @DrJamesEHansen 1/10
Actually, Jim, Rocky is about 10% right.

Generally speaking, the so-called (albeit misnamed) "greenhouse effect" occurs when radiatively active gases in the atmosphere (triatomic & higher) absorb outgoing LW IR radiation emitted by the Earth. That warms the atmosphere.

@Rocky35418823 @fischerfischy @Anvndarnamn5 @GordonDHG_clim8 @Faktantarkast10 @Michael_D_Crow @JimBowersclimb @SniemN @heinsenberger @ChrisBBacon3 @Willard1951 @TheDisproof @CraigM350 @DenisDaly @ubique60 @Climatehope2 @Jaisans @CDMarshall7 @Data79504085 @glinch72 @Ceist8 @EthonRaptor @Hji45519156 @ammocrypta @RMcgillss @ShaMikaWhoSeeks @paligap17 @JustThi30117912 @AristotleMrs @S_D_Mannix @BointonGiles @MaggieL @Willy1000 @Mark_A_Lunn @AuroriaTwittori @3GHtweets @RushhourP @MartinJBern @gstrandberg1 @ItsTheAtmospher @Jakegsm @EricWil06256732 @DTGvmd @wille99 @PaulDFarrar @KCTaz @Valja46Zhark5 @drochir_thonnuk @DrJamesEHansen 2/ But CO2 is a special case:
There's so much CO2 already in the air that, at wavelengths where CO2 absorbs most strongly (about 14.2 µm to 15.8 µm), virtually all outgoing LW IR is already absorbed. So you might think adding more would have no effect. But that's not quite right.

@Rocky35418823 @fischerfischy @Anvndarnamn5 @GordonDHG_clim8 @Faktantarkast10 @Michael_D_Crow @JimBowersclimb @SniemN @heinsenberger @ChrisBBacon3 @Willard1951 @TheDisproof @CraigM350 @DenisDaly @ubique60 @Climatehope2 @Jaisans @CDMarshall7 @Data79504085 @glinch72 @Ceist8 @EthonRaptor @Hji45519156 @ammocrypta @RMcgillss @ShaMikaWhoSeeks @paligap17 @JustThi30117912 @AristotleMrs @S_D_Mannix @BointonGiles @MaggieL @Willy1000 @Mark_A_Lunn @AuroriaTwittori @3GHtweets @RushhourP @MartinJBern @gstrandberg1 @ItsTheAtmospher @Jakegsm @EricWil06256732 @DTGvmd @wille99 @PaulDFarrar @KCTaz @Valja46Zhark5 @drochir_thonnuk @DrJamesEHansen 3/ Even in CO2's "15µm" (14.2 - 15.8 µm) absorption band, radiation from Earth does escape to outer space. But it's emitted by CO2 in the air, not by the surface. It comes from altitudes high enough that the atmosphere is so thin that IR photons can escape without being absorbed.

@Rocky35418823 @fischerfischy @Anvndarnamn5 @GordonDHG_clim8 @Faktantarkast10 @Michael_D_Crow @JimBowersclimb @SniemN @heinsenberger @ChrisBBacon3 @Willard1951 @TheDisproof @CraigM350 @DenisDaly @ubique60 @Climatehope2 @Jaisans @CDMarshall7 @Data79504085 @glinch72 @Ceist8 @EthonRaptor @Hji45519156 @ammocrypta @RMcgillss @ShaMikaWhoSeeks @paligap17 @JustThi30117912 @AristotleMrs @S_D_Mannix @BointonGiles @MaggieL @Willy1000 @Mark_A_Lunn @AuroriaTwittori @3GHtweets @RushhourP @MartinJBern @gstrandberg1 @ItsTheAtmospher @Jakegsm @EricWil06256732 @DTGvmd @wille99 @PaulDFarrar @KCTaz @Valja46Zhark5 @drochir_thonnuk @DrJamesEHansen 4/ Of course the surface does emit 15µm IR, but it's inevitably absorbed by CO2 in the air. That CO2 also emits 15µm IR, which is absorbed by other CO2 molecules, etc. Those constant exchanges of energy (along with air movement etc) spread the absorbed energy thru the atmosphere.

@Rocky35418823 @fischerfischy @Anvndarnamn5 @GordonDHG_clim8 @Faktantarkast10 @Michael_D_Crow @JimBowersclimb @SniemN @heinsenberger @ChrisBBacon3 @Willard1951 @TheDisproof @CraigM350 @DenisDaly @ubique60 @Climatehope2 @Jaisans @CDMarshall7 @Data79504085 @glinch72 @Ceist8 @EthonRaptor @Hji45519156 @ammocrypta @RMcgillss @ShaMikaWhoSeeks @paligap17 @JustThi30117912 @AristotleMrs @S_D_Mannix @BointonGiles @MaggieL @Willy1000 @Mark_A_Lunn @AuroriaTwittori @3GHtweets @RushhourP @MartinJBern @gstrandberg1 @ItsTheAtmospher @Jakegsm @EricWil06256732 @DTGvmd @wille99 @PaulDFarrar @KCTaz @Valja46Zhark5 @drochir_thonnuk @DrJamesEHansen 5/ But at high altitudes, the air is so thin that a substantial portion of the emitted LW IR photons from CO2 in the air escape it to outer space, without encountering and being absorbed by other CO2 molecules.

@Rocky35418823 @fischerfischy @Anvndarnamn5 @GordonDHG_clim8 @Faktantarkast10 @Michael_D_Crow @JimBowersclimb @SniemN @heinsenberger @ChrisBBacon3 @Willard1951 @TheDisproof @CraigM350 @DenisDaly @ubique60 @Climatehope2 @Jaisans @CDMarshall7 @Data79504085 @glinch72 @Ceist8 @EthonRaptor @Hji45519156 @ammocrypta @RMcgillss @ShaMikaWhoSeeks @paligap17 @JustThi30117912 @AristotleMrs @S_D_Mannix @BointonGiles @MaggieL @Willy1000 @Mark_A_Lunn @AuroriaTwittori @3GHtweets @RushhourP @MartinJBern @gstrandberg1 @ItsTheAtmospher @Jakegsm @EricWil06256732 @DTGvmd @wille99 @PaulDFarrar @KCTaz @Valja46Zhark5 @drochir_thonnuk @DrJamesEHansen 6/ From that comes the concept of "emission height." For a given wavelength, if you look down from orbit with a spectrometer, there's an average altitude for the outgoing LW IR photons you see. We call that the "effective emission height."
(At 10µm w/ no clouds it's the surface!)

@Rocky35418823 @fischerfischy @Anvndarnamn5 @GordonDHG_clim8 @Faktantarkast10 @Michael_D_Crow @JimBowersclimb @SniemN @heinsenberger @ChrisBBacon3 @Willard1951 @TheDisproof @CraigM350 @DenisDaly @ubique60 @Climatehope2 @Jaisans @CDMarshall7 @Data79504085 @glinch72 @Ceist8 @EthonRaptor @Hji45519156 @ammocrypta @RMcgillss @ShaMikaWhoSeeks @paligap17 @JustThi30117912 @AristotleMrs @S_D_Mannix @BointonGiles @MaggieL @Willy1000 @Mark_A_Lunn @AuroriaTwittori @3GHtweets @RushhourP @MartinJBern @gstrandberg1 @ItsTheAtmospher @Jakegsm @EricWil06256732 @DTGvmd @wille99 @PaulDFarrar @KCTaz @Valja46Zhark5 @drochir_thonnuk @DrJamesEHansen 7/ A common explanation for why additional CO2 added to the atmosphere still has a warming effect, even though its 15µm absorption band is "saturated," goes like this:

"By adding CO2 we make radiation to space come from higher, colder air, reducing flow of radiation to space."

@Rocky35418823 @fischerfischy @Anvndarnamn5 @GordonDHG_clim8 @Faktantarkast10 @Michael_D_Crow @JimBowersclimb @SniemN @heinsenberger @ChrisBBacon3 @Willard1951 @TheDisproof @CraigM350 @DenisDaly @ubique60 @Climatehope2 @Jaisans @CDMarshall7 @Data79504085 @glinch72 @Ceist8 @EthonRaptor @Hji45519156 @ammocrypta @RMcgillss @ShaMikaWhoSeeks @paligap17 @JustThi30117912 @AristotleMrs @S_D_Mannix @BointonGiles @MaggieL @Willy1000 @Mark_A_Lunn @AuroriaTwittori @3GHtweets @RushhourP @MartinJBern @gstrandberg1 @ItsTheAtmospher @Jakegsm @EricWil06256732 @DTGvmd @wille99 @PaulDFarrar @KCTaz @Valja46Zhark5 @drochir_thonnuk @DrJamesEHansen 8/ However, that's mostly incorrect. You see, the LW IR effective emission height is not a single number. It varies by wavelength, as explained here by physicist Clive Best:

andthentheresphysics.wordpress.com/2014/03/05/eff…

clivebest.com/blog/wp-conten…

@Rocky35418823 @fischerfischy @Anvndarnamn5 @GordonDHG_clim8 @Faktantarkast10 @Michael_D_Crow @JimBowersclimb @SniemN @heinsenberger @ChrisBBacon3 @Willard1951 @TheDisproof @CraigM350 @DenisDaly @ubique60 @Climatehope2 @Jaisans @CDMarshall7 @Data79504085 @glinch72 @Ceist8 @EthonRaptor @Hji45519156 @ammocrypta @RMcgillss @ShaMikaWhoSeeks @paligap17 @JustThi30117912 @AristotleMrs @S_D_Mannix @BointonGiles @MaggieL @Willy1000 @Mark_A_Lunn @AuroriaTwittori @3GHtweets @RushhourP @MartinJBern @gstrandberg1 @ItsTheAtmospher @Jakegsm @EricWil06256732 @DTGvmd @wille99 @PaulDFarrar @KCTaz @Valja46Zhark5 @drochir_thonnuk @DrJamesEHansen 9/ It is true that effective emission height for CO2's 15µm band rises as the CO2 concentration increases. However, that "higher air" is NOT necessarily "colder air." You see, over most of the 15µm band the effective emission height is near the tropopause.
sealevel.info/VerticalStruct…

@Rocky35418823 @fischerfischy @Anvndarnamn5 @GordonDHG_clim8 @Faktantarkast10 @Michael_D_Crow @JimBowersclimb @SniemN @heinsenberger @ChrisBBacon3 @Willard1951 @TheDisproof @CraigM350 @DenisDaly @ubique60 @Climatehope2 @Jaisans @CDMarshall7 @Data79504085 @glinch72 @Ceist8 @EthonRaptor @Hji45519156 @ammocrypta @RMcgillss @ShaMikaWhoSeeks @paligap17 @JustThi30117912 @AristotleMrs @S_D_Mannix @BointonGiles @MaggieL @Willy1000 @Mark_A_Lunn @AuroriaTwittori @3GHtweets @RushhourP @MartinJBern @gstrandberg1 @ItsTheAtmospher @Jakegsm @EricWil06256732 @DTGvmd @wille99 @PaulDFarrar @KCTaz @Valja46Zhark5 @drochir_thonnuk @DrJamesEHansen 10/10
At the tropopause, an increase in altitude does NOT cause a decrease in temperature.

The result of that fact is that most of CO2's warming effect is a result of weakly absorbed "fringe" wavelengths, where the effective emission height is lower.