Thread by @ncdave4life

@Willard1951 @Jaisans @AndyJ93519624 @IngersolRobert @FChecker76 @Data79504085 @AristotleMrs @dan613 @JohnDublin10 @TWTThisIsNow @ammocrypta @geoguy_usa104 @Stephen90045069 @NonlinearDarren @Climatehope2 @flyonthewall182 @glinch72 @GregTruman4 @GregCoo85844909 @25_cycle @BrknMan @don85375 @ZSRenn @1tsakeeper @LizHersch1 @KCTaz @JustThi30117912 @gregchoat @Anvndarnamn5 @B_Bolshevik100 @NickMcGinley1 @RobMeekel @cieloyla @EthonRaptor @BradPKeyes @JSegor @Mark_A_Lunn @BridgetHolmstro @jwickers @0Sundance @PeterMayfitz @omahas @TonyBoloni8 @TheDisproof @DanCady @Keeper_86 @Jamz129 @CallMeBlaise1 @ostinado @sciam Stop changing the subject.

Starting with the chilly 1970s is a cherry-pick.

Also, to show 1.2°C of warming you've got to ignore the best quality data and use something like GISTEMP, and end with the 2016 El Nino.

But that's not our topic.
sealevel.info/newsweek_old.h…

@Willard1951 @Jaisans @AndyJ93519624 @IngersolRobert @FChecker76 @Data79504085 @AristotleMrs @dan613 @JohnDublin10 @TWTThisIsNow @ammocrypta @geoguy_usa104 @Stephen90045069 @NonlinearDarren @Climatehope2 @flyonthewall182 @glinch72 @GregTruman4 @GregCoo85844909 @25_cycle @BrknMan @don85375 @ZSRenn @1tsakeeper @LizHersch1 @KCTaz @JustThi30117912 @gregchoat @Anvndarnamn5 @B_Bolshevik100 @NickMcGinley1 @RobMeekel @cieloyla @EthonRaptor @BradPKeyes @JSegor @Mark_A_Lunn @BridgetHolmstro @jwickers @0Sundance @PeterMayfitz @omahas @TonyBoloni8 @TheDisproof @DanCady @Keeper_86 @Jamz129 @CallMeBlaise1 @ostinado @sciam We're talking about the significance of the estimated 0.6 W/m² TOA radiative imbalance, and how little warming "in the pipe" it represents.

(That's why large estimates of ECS ÷ TCR are surely wrong, BTW.)

Also, this...

@Willard1951 @Jaisans @AndyJ93519624 @IngersolRobert @FChecker76 @Data79504085 @AristotleMrs @dan613 @JohnDublin10 @TWTThisIsNow @ammocrypta @geoguy_usa104 @Stephen90045069 @NonlinearDarren @Climatehope2 @flyonthewall182 @glinch72 @GregTruman4 @GregCoo85844909 @25_cycle @BrknMan @don85375 @ZSRenn @1tsakeeper @LizHersch1 @KCTaz @JustThi30117912 @gregchoat @Anvndarnamn5 @B_Bolshevik100 @NickMcGinley1 @RobMeekel @cieloyla @EthonRaptor @BradPKeyes @JSegor @Mark_A_Lunn @BridgetHolmstro @jwickers @0Sundance @PeterMayfitz @omahas @TonyBoloni8 @TheDisproof @DanCady @Keeper_86 @Jamz129 @CallMeBlaise1 @ostinado @sciam 1/12.
"Current" temperature trend depends on the time period you pick & temperature index you use, but the best temperature index (UAH6) shows about 0.6°C in 42 years. At that rate we could get another 1.1°C by 2100. (Yawn.)

woodfortrees.org/plot/uah6/mean…

But…

@Willard1951 @Jaisans @AndyJ93519624 @IngersolRobert @FChecker76 @Data79504085 @AristotleMrs @dan613 @JohnDublin10 @TWTThisIsNow @ammocrypta @geoguy_usa104 @Stephen90045069 @NonlinearDarren @Climatehope2 @flyonthewall182 @glinch72 @GregTruman4 @GregCoo85844909 @25_cycle @BrknMan @don85375 @ZSRenn @1tsakeeper @LizHersch1 @KCTaz @JustThi30117912 @gregchoat @Anvndarnamn5 @B_Bolshevik100 @NickMcGinley1 @RobMeekel @cieloyla @EthonRaptor @BradPKeyes @JSegor @Mark_A_Lunn @BridgetHolmstro @jwickers @0Sundance @PeterMayfitz @omahas @TonyBoloni8 @TheDisproof @DanCady @Keeper_86 @Jamz129 @CallMeBlaise1 @ostinado @sciam 2/12.
Of course the last 1°C of warming we got was clearly beneficial. So the prospect of another 1.1°C isn't scary. In the American breadbasket states, farmers can compensate for that much warming by planting about one week earlier.

@Willard1951 @Jaisans @AndyJ93519624 @IngersolRobert @FChecker76 @Data79504085 @AristotleMrs @dan613 @JohnDublin10 @TWTThisIsNow @ammocrypta @geoguy_usa104 @Stephen90045069 @NonlinearDarren @Climatehope2 @flyonthewall182 @glinch72 @GregTruman4 @GregCoo85844909 @25_cycle @BrknMan @don85375 @ZSRenn @1tsakeeper @LizHersch1 @KCTaz @JustThi30117912 @gregchoat @Anvndarnamn5 @B_Bolshevik100 @NickMcGinley1 @RobMeekel @cieloyla @EthonRaptor @BradPKeyes @JSegor @Mark_A_Lunn @BridgetHolmstro @jwickers @0Sundance @PeterMayfitz @omahas @TonyBoloni8 @TheDisproof @DanCady @Keeper_86 @Jamz129 @CallMeBlaise1 @ostinado @sciam 3/12.
But that rate of warming certainly won't continue. Even if you assume it's all been anthropogenic, a continuation of that rate of warming would require a continuing linear increase in anthropogenic radiative forcing.

@Willard1951 @Jaisans @AndyJ93519624 @IngersolRobert @FChecker76 @Data79504085 @AristotleMrs @dan613 @JohnDublin10 @TWTThisIsNow @ammocrypta @geoguy_usa104 @Stephen90045069 @NonlinearDarren @Climatehope2 @flyonthewall182 @glinch72 @GregTruman4 @GregCoo85844909 @25_cycle @BrknMan @don85375 @ZSRenn @1tsakeeper @LizHersch1 @KCTaz @JustThi30117912 @gregchoat @Anvndarnamn5 @B_Bolshevik100 @NickMcGinley1 @RobMeekel @cieloyla @EthonRaptor @BradPKeyes @JSegor @Mark_A_Lunn @BridgetHolmstro @jwickers @0Sundance @PeterMayfitz @omahas @TonyBoloni8 @TheDisproof @DanCady @Keeper_86 @Jamz129 @CallMeBlaise1 @ostinado @sciam 4/12.
Because CO2's forcing is logarithmically diminishing, a continuing linear increase in the forcing from CO2 would require a modestly accelerating increase in rate of CO2 level rise.

@Willard1951 @Jaisans @AndyJ93519624 @IngersolRobert @FChecker76 @Data79504085 @AristotleMrs @dan613 @JohnDublin10 @TWTThisIsNow @ammocrypta @geoguy_usa104 @Stephen90045069 @NonlinearDarren @Climatehope2 @flyonthewall182 @glinch72 @GregTruman4 @GregCoo85844909 @25_cycle @BrknMan @don85375 @ZSRenn @1tsakeeper @LizHersch1 @KCTaz @JustThi30117912 @gregchoat @Anvndarnamn5 @B_Bolshevik100 @NickMcGinley1 @RobMeekel @cieloyla @EthonRaptor @BradPKeyes @JSegor @Mark_A_Lunn @BridgetHolmstro @jwickers @0Sundance @PeterMayfitz @omahas @TonyBoloni8 @TheDisproof @DanCady @Keeper_86 @Jamz129 @CallMeBlaise1 @ostinado @sciam 5/12.
But, even more importantly, even to get a linear increase in CO2 level would require a drastic acceleration in emissions, because of the powerful negative CO2 feedbacks which remove CO2 at an accelerating pace as the level rises.

@Willard1951 @Jaisans @AndyJ93519624 @IngersolRobert @FChecker76 @Data79504085 @AristotleMrs @dan613 @JohnDublin10 @TWTThisIsNow @ammocrypta @geoguy_usa104 @Stephen90045069 @NonlinearDarren @Climatehope2 @flyonthewall182 @glinch72 @GregTruman4 @GregCoo85844909 @25_cycle @BrknMan @don85375 @ZSRenn @1tsakeeper @LizHersch1 @KCTaz @JustThi30117912 @gregchoat @Anvndarnamn5 @B_Bolshevik100 @NickMcGinley1 @RobMeekel @cieloyla @EthonRaptor @BradPKeyes @JSegor @Mark_A_Lunn @BridgetHolmstro @jwickers @0Sundance @PeterMayfitz @omahas @TonyBoloni8 @TheDisproof @DanCady @Keeper_86 @Jamz129 @CallMeBlaise1 @ostinado @sciam 6/12.
Fossil fuel resource constraints & negative CO2 feedbacks ensure CO2 level increases can't continue to accelerate for 79 yrs, nor anything close.
researchgate.net/publication/30…

@Willard1951 @Jaisans @AndyJ93519624 @IngersolRobert @FChecker76 @Data79504085 @AristotleMrs @dan613 @JohnDublin10 @TWTThisIsNow @ammocrypta @geoguy_usa104 @Stephen90045069 @NonlinearDarren @Climatehope2 @flyonthewall182 @glinch72 @GregTruman4 @GregCoo85844909 @25_cycle @BrknMan @don85375 @ZSRenn @1tsakeeper @LizHersch1 @KCTaz @JustThi30117912 @gregchoat @Anvndarnamn5 @B_Bolshevik100 @NickMcGinley1 @RobMeekel @cieloyla @EthonRaptor @BradPKeyes @JSegor @Mark_A_Lunn @BridgetHolmstro @jwickers @0Sundance @PeterMayfitz @omahas @TonyBoloni8 @TheDisproof @DanCady @Keeper_86 @Jamz129 @CallMeBlaise1 @ostinado @sciam 7/12.
That means we should much LESS warming than "another 1.1°C by 2100."

Let's see how much less.

CO2 level was 337 ppmv in 1979. Over the next 42 years it rose to 415 ppmv. That's 30% of a doubling.
google.com/search?q=log2%…

@Willard1951 @Jaisans @AndyJ93519624 @IngersolRobert @FChecker76 @Data79504085 @AristotleMrs @dan613 @JohnDublin10 @TWTThisIsNow @ammocrypta @geoguy_usa104 @Stephen90045069 @NonlinearDarren @Climatehope2 @flyonthewall182 @glinch72 @GregTruman4 @GregCoo85844909 @25_cycle @BrknMan @don85375 @ZSRenn @1tsakeeper @LizHersch1 @KCTaz @JustThi30117912 @gregchoat @Anvndarnamn5 @B_Bolshevik100 @NickMcGinley1 @RobMeekel @cieloyla @EthonRaptor @BradPKeyes @JSegor @Mark_A_Lunn @BridgetHolmstro @jwickers @0Sundance @PeterMayfitz @omahas @TonyBoloni8 @TheDisproof @DanCady @Keeper_86 @Jamz129 @CallMeBlaise1 @ostinado @sciam 8/12.
UAH shows ≈0.6°C of warming over that 42 years.
woodfortrees.org/plot/uah6/mean…

At first glance, 0.6°C from 30% of a doubling suggests 2°C per doubling.

But about 1/3 of the warming was from other factors: other GHGs, particulate/aerosol pollution abatement, etc.

@Willard1951 @Jaisans @AndyJ93519624 @IngersolRobert @FChecker76 @Data79504085 @AristotleMrs @dan613 @JohnDublin10 @TWTThisIsNow @ammocrypta @geoguy_usa104 @Stephen90045069 @NonlinearDarren @Climatehope2 @flyonthewall182 @glinch72 @GregTruman4 @GregCoo85844909 @25_cycle @BrknMan @don85375 @ZSRenn @1tsakeeper @LizHersch1 @KCTaz @JustThi30117912 @gregchoat @Anvndarnamn5 @B_Bolshevik100 @NickMcGinley1 @RobMeekel @cieloyla @EthonRaptor @BradPKeyes @JSegor @Mark_A_Lunn @BridgetHolmstro @jwickers @0Sundance @PeterMayfitz @omahas @TonyBoloni8 @TheDisproof @DanCady @Keeper_86 @Jamz129 @CallMeBlaise1 @ostinado @sciam 9/12.
That suggests a "practical climate sensitivity" (between TCR and ECS) of about 2/3 of 2°C = 1.33°C/doubling.

We'll come back to that figure in a bit.

@Willard1951 @Jaisans @AndyJ93519624 @IngersolRobert @FChecker76 @Data79504085 @AristotleMrs @dan613 @JohnDublin10 @TWTThisIsNow @ammocrypta @geoguy_usa104 @Stephen90045069 @NonlinearDarren @Climatehope2 @flyonthewall182 @glinch72 @GregTruman4 @GregCoo85844909 @25_cycle @BrknMan @don85375 @ZSRenn @1tsakeeper @LizHersch1 @KCTaz @JustThi30117912 @gregchoat @Anvndarnamn5 @B_Bolshevik100 @NickMcGinley1 @RobMeekel @cieloyla @EthonRaptor @BradPKeyes @JSegor @Mark_A_Lunn @BridgetHolmstro @jwickers @0Sundance @PeterMayfitz @omahas @TonyBoloni8 @TheDisproof @DanCady @Keeper_86 @Jamz129 @CallMeBlaise1 @ostinado @sciam 10/12.
Some people think CO2 emissions peaked in 2019. (I don't.)

But even if emissions increase 20%, and stay at that increased rate for the next few centuries, the negative feedbacks ensure that CO2 level will plateau at only ≈550 ppmv.

That's only 41% of a doubling.

@Willard1951 @Jaisans @AndyJ93519624 @IngersolRobert @FChecker76 @Data79504085 @AristotleMrs @dan613 @JohnDublin10 @TWTThisIsNow @ammocrypta @geoguy_usa104 @Stephen90045069 @NonlinearDarren @Climatehope2 @flyonthewall182 @glinch72 @GregTruman4 @GregCoo85844909 @25_cycle @BrknMan @don85375 @ZSRenn @1tsakeeper @LizHersch1 @KCTaz @JustThi30117912 @gregchoat @Anvndarnamn5 @B_Bolshevik100 @NickMcGinley1 @RobMeekel @cieloyla @EthonRaptor @BradPKeyes @JSegor @Mark_A_Lunn @BridgetHolmstro @jwickers @0Sundance @PeterMayfitz @omahas @TonyBoloni8 @TheDisproof @DanCady @Keeper_86 @Jamz129 @CallMeBlaise1 @ostinado @sciam 11/12.
41% of 1.33°C = 0.55°C of additional eventual warming over coming centuries, from indefinitely continuing CO2 emissions at a rate 20% greater than present.

Even if you think UAH is 30% low, it'd still be only 0.72°C of additional eventual warming over coming centuries.

@Willard1951 @Jaisans @AndyJ93519624 @IngersolRobert @FChecker76 @Data79504085 @AristotleMrs @dan613 @JohnDublin10 @TWTThisIsNow @ammocrypta @geoguy_usa104 @Stephen90045069 @NonlinearDarren @Climatehope2 @flyonthewall182 @glinch72 @GregTruman4 @GregCoo85844909 @25_cycle @BrknMan @don85375 @ZSRenn @1tsakeeper @LizHersch1 @KCTaz @JustThi30117912 @gregchoat @Anvndarnamn5 @B_Bolshevik100 @NickMcGinley1 @RobMeekel @cieloyla @EthonRaptor @BradPKeyes @JSegor @Mark_A_Lunn @BridgetHolmstro @jwickers @0Sundance @PeterMayfitz @omahas @TonyBoloni8 @TheDisproof @DanCady @Keeper_86 @Jamz129 @CallMeBlaise1 12/12.
To that you have to add or subtract other factors that affect temperatures, like other GHGs. But, even so, it is plain that the possible additional warming from continuing CO2 emissions is modest and benign.

@rattibha @threadreaderapp unroll / compile it, please.