Thread by @ncdave4life

@Willard1951 @NolanCarlton2 @JusticeTrudeau @Climatehope2 @CarrudoDon @priscian @Ceist8 @AristotleMrs @Jaisans @BenKoby1911 @Anvndarnamn5 @fischerfischy @Michael_D_Crow @DenisDaly @Joeyd87745119 @Mark_A_Lunn @Devonian1342 @S_D_Mannix @Veritatem2021 @Data79504085 @Hji45519156 @glinch72 @waxliberty @SuperFoxyLoxy @ChrisBBacon3 @JimBowersclimb @JaapTitulaer @wjack76995 @Rocky35418823 @NobaconEgbert @balls95652097 @JustThi30117912 @SniemN @BointonGiles @ammocrypta @SeekerTheGreat1 @ubique60 @CDMarshall7 @EthonRaptor @RMcgillss @paligap17 @TheDisproof @MaggieL @Willy1000 @AuroriaTwittori @3GHtweets @RushhourP @MartinJBern @gstrandberg1 @BerkeleyEarth 1/11》
Kiehl & Trenberth 1997 attributed 67% of GHG warming to CO2.
journals.ametsoc.org/view/journals/…

@Willard1951 @NolanCarlton2 @JusticeTrudeau @Climatehope2 @CarrudoDon @priscian @Ceist8 @AristotleMrs @Jaisans @BenKoby1911 @Anvndarnamn5 @fischerfischy @Michael_D_Crow @DenisDaly @Joeyd87745119 @Mark_A_Lunn @Devonian1342 @S_D_Mannix @Veritatem2021 @Data79504085 @Hji45519156 @glinch72 @waxliberty @SuperFoxyLoxy @ChrisBBacon3 @JimBowersclimb @JaapTitulaer @wjack76995 @Rocky35418823 @NobaconEgbert @balls95652097 @JustThi30117912 @SniemN @BointonGiles @ammocrypta @SeekerTheGreat1 @ubique60 @CDMarshall7 @EthonRaptor @RMcgillss @paligap17 @TheDisproof @MaggieL @Willy1000 @AuroriaTwittori @3GHtweets @RushhourP @MartinJBern @gstrandberg1 @BerkeleyEarth 2/11》
Myhre 1998 showed about 58% attributed to CO2.
sealevel.info/Myhre1998_Tabl…
agupubs.onlinelibrary.wiley.com/doi/abs/10.102…
sealevel.info/Myhre1998_Tabl…
sealevel.info/Myhre1997_Tabl…
sealevel.info/Myhre1998_Tabl…

@Willard1951 @NolanCarlton2 @JusticeTrudeau @Climatehope2 @CarrudoDon @priscian @Ceist8 @AristotleMrs @Jaisans @BenKoby1911 @Anvndarnamn5 @fischerfischy @Michael_D_Crow @DenisDaly @Joeyd87745119 @Mark_A_Lunn @Devonian1342 @S_D_Mannix @Veritatem2021 @Data79504085 @Hji45519156 @glinch72 @waxliberty @SuperFoxyLoxy @ChrisBBacon3 @JimBowersclimb @JaapTitulaer @wjack76995 @Rocky35418823 @NobaconEgbert @balls95652097 @JustThi30117912 @SniemN @BointonGiles @ammocrypta @SeekerTheGreat1 @ubique60 @CDMarshall7 @EthonRaptor @RMcgillss @paligap17 @TheDisproof @MaggieL @Willy1000 @AuroriaTwittori @3GHtweets @RushhourP @MartinJBern @gstrandberg1 @BerkeleyEarth 3/11》
Note that there're several ways of counting the percentage attribution to CO2, corresponding to various questions you could ask. Each of these questions will yield a somewhat different answer:

@Willard1951 @NolanCarlton2 @JusticeTrudeau @Climatehope2 @CarrudoDon @priscian @Ceist8 @AristotleMrs @Jaisans @BenKoby1911 @Anvndarnamn5 @fischerfischy @Michael_D_Crow @DenisDaly @Joeyd87745119 @Mark_A_Lunn @Devonian1342 @S_D_Mannix @Veritatem2021 @Data79504085 @Hji45519156 @glinch72 @waxliberty @SuperFoxyLoxy @ChrisBBacon3 @JimBowersclimb @JaapTitulaer @wjack76995 @Rocky35418823 @NobaconEgbert @balls95652097 @JustThi30117912 @SniemN @BointonGiles @ammocrypta @SeekerTheGreat1 @ubique60 @CDMarshall7 @EthonRaptor @RMcgillss @paligap17 @TheDisproof @MaggieL @Willy1000 @AuroriaTwittori @3GHtweets @RushhourP @MartinJBern @gstrandberg1 @BerkeleyEarth 4/11》
Q1: If GHG's ERF since the dawn of the industrial age increased by X, then how much LESS, as a % of X, would it have increased if the CO2 level had remained unchanged, and only the OTHER noncondensing GHGs had increased?

@Willard1951 @NolanCarlton2 @JusticeTrudeau @Climatehope2 @CarrudoDon @priscian @Ceist8 @AristotleMrs @Jaisans @BenKoby1911 @Anvndarnamn5 @fischerfischy @Michael_D_Crow @DenisDaly @Joeyd87745119 @Mark_A_Lunn @Devonian1342 @S_D_Mannix @Veritatem2021 @Data79504085 @Hji45519156 @glinch72 @waxliberty @SuperFoxyLoxy @ChrisBBacon3 @JimBowersclimb @JaapTitulaer @wjack76995 @Rocky35418823 @NobaconEgbert @balls95652097 @JustThi30117912 @SniemN @BointonGiles @ammocrypta @SeekerTheGreat1 @ubique60 @CDMarshall7 @EthonRaptor @RMcgillss @paligap17 @TheDisproof @MaggieL @Willy1000 @AuroriaTwittori @3GHtweets @RushhourP @MartinJBern @gstrandberg1 @BerkeleyEarth 5/11》
Q2: If GHG's ERF since the dawn of the industrial age increased by X, then how much would it have increased, as a % of X, if ONLY the CO2 level had changed, and the other noncondensing GHGs had not changed in their concentrations?

@Willard1951 @NolanCarlton2 @JusticeTrudeau @Climatehope2 @CarrudoDon @priscian @Ceist8 @AristotleMrs @Jaisans @BenKoby1911 @Anvndarnamn5 @fischerfischy @Michael_D_Crow @DenisDaly @Joeyd87745119 @Mark_A_Lunn @Devonian1342 @S_D_Mannix @Veritatem2021 @Data79504085 @Hji45519156 @glinch72 @waxliberty @SuperFoxyLoxy @ChrisBBacon3 @JimBowersclimb @JaapTitulaer @wjack76995 @Rocky35418823 @NobaconEgbert @balls95652097 @JustThi30117912 @SniemN @BointonGiles @ammocrypta @SeekerTheGreat1 @ubique60 @CDMarshall7 @EthonRaptor @RMcgillss @paligap17 @TheDisproof @MaggieL @Willy1000 @AuroriaTwittori @3GHtweets @RushhourP @MartinJBern @gstrandberg1 @BerkeleyEarth 6/11》
Because of overlap between the absorption spectra of the various GHGs, the answer to Q1 is a lower percentage than the answer to Q2. (You could also use the average of those two answers.)

@Willard1951 @NolanCarlton2 @JusticeTrudeau @Climatehope2 @CarrudoDon @priscian @Ceist8 @AristotleMrs @Jaisans @BenKoby1911 @Anvndarnamn5 @fischerfischy @Michael_D_Crow @DenisDaly @Joeyd87745119 @Mark_A_Lunn @Devonian1342 @S_D_Mannix @Veritatem2021 @Data79504085 @Hji45519156 @glinch72 @waxliberty @SuperFoxyLoxy @ChrisBBacon3 @JimBowersclimb @JaapTitulaer @wjack76995 @Rocky35418823 @NobaconEgbert @balls95652097 @JustThi30117912 @SniemN @BointonGiles @ammocrypta @SeekerTheGreat1 @ubique60 @CDMarshall7 @EthonRaptor @RMcgillss @paligap17 @TheDisproof @MaggieL @Willy1000 @AuroriaTwittori @3GHtweets @RushhourP @MartinJBern @gstrandberg1 @BerkeleyEarth 7/11》
Q3 & Q4: You could ask the same questions as Q1 & Q2, respectively, but let "X" be total anthropogenic ERF (including aerosol/particulate effects), rather than just GHG ERF.

@Willard1951 @NolanCarlton2 @JusticeTrudeau @Climatehope2 @CarrudoDon @priscian @Ceist8 @AristotleMrs @Jaisans @BenKoby1911 @Anvndarnamn5 @fischerfischy @Michael_D_Crow @DenisDaly @Joeyd87745119 @Mark_A_Lunn @Devonian1342 @S_D_Mannix @Veritatem2021 @Data79504085 @Hji45519156 @glinch72 @waxliberty @SuperFoxyLoxy @ChrisBBacon3 @JimBowersclimb @JaapTitulaer @wjack76995 @Rocky35418823 @NobaconEgbert @balls95652097 @JustThi30117912 @SniemN @BointonGiles @ammocrypta @SeekerTheGreat1 @ubique60 @CDMarshall7 @EthonRaptor @RMcgillss @paligap17 @TheDisproof @MaggieL @Willy1000 @AuroriaTwittori @3GHtweets @RushhourP @MartinJBern @gstrandberg1 @BerkeleyEarth 8/11》
Because anthropogenic aerosol/particulate forcing is highly uncertain, but probably negative since the dawn of the industrial age, the percentages you'd calculate this way (Q3 & Q4) are generally higher but much more uncertain than the answers to Q1 & Q2.

@Willard1951 @NolanCarlton2 @JusticeTrudeau @Climatehope2 @CarrudoDon @priscian @Ceist8 @AristotleMrs @Jaisans @BenKoby1911 @Anvndarnamn5 @fischerfischy @Michael_D_Crow @DenisDaly @Joeyd87745119 @Mark_A_Lunn @Devonian1342 @S_D_Mannix @Veritatem2021 @Data79504085 @Hji45519156 @glinch72 @waxliberty @SuperFoxyLoxy @ChrisBBacon3 @JimBowersclimb @JaapTitulaer @wjack76995 @Rocky35418823 @NobaconEgbert @balls95652097 @JustThi30117912 @SniemN @BointonGiles @ammocrypta @SeekerTheGreat1 @ubique60 @CDMarshall7 @EthonRaptor @RMcgillss @paligap17 @TheDisproof @MaggieL @Willy1000 @AuroriaTwittori @3GHtweets @RushhourP @MartinJBern @gstrandberg1 @BerkeleyEarth 9/11》
What's more, the various anthropogenic forcings have not changed in a fixed ratio, so the percentage of a change in radiative forcing attributable to CO2 varies considerably depending on what time period you consider.

@Willard1951 @NolanCarlton2 @JusticeTrudeau @Climatehope2 @CarrudoDon @priscian @Ceist8 @AristotleMrs @Jaisans @BenKoby1911 @Anvndarnamn5 @fischerfischy @Michael_D_Crow @DenisDaly @Joeyd87745119 @Mark_A_Lunn @Devonian1342 @S_D_Mannix @Veritatem2021 @Data79504085 @Hji45519156 @glinch72 @waxliberty @SuperFoxyLoxy @ChrisBBacon3 @JimBowersclimb @JaapTitulaer @wjack76995 @Rocky35418823 @NobaconEgbert @balls95652097 @JustThi30117912 @SniemN @BointonGiles @ammocrypta @SeekerTheGreat1 @ubique60 @CDMarshall7 @EthonRaptor @RMcgillss @paligap17 @TheDisproof @MaggieL @Willy1000 @AuroriaTwittori @3GHtweets @RushhourP @MartinJBern @gstrandberg1 @BerkeleyEarth 10/11》
For recent years, air pollution abatement has probably made aerosol/particulate forcing positive instead of negative. That is, some of the recent slight observed global warming is due to cleaner air, rather than GHGs.

uni-leipzig.de/en/newsdetail/…

topteknews.net/international-…