Thread by @ncdave4life

@Gladfly1 @rdqBlueRidge @TWTThisIsNow @25_cycle @Rose1962bush @SlymasterSteven @ejwwest @Willard1951 @insane_voice @AGWIsHappening @Gordon_DHG @TheDisproof @Stephen90045069 @AristotleMrs @Canadianworker2 @PierreTherrie19 @IceAge2150 @Nockit1 @JohnGiuliano7 @Robert76907841 @1Astroturf @UlaLomu @Moderna5G_666 @MikeDel21893959 @DanielMcDonald4 @mel_wright123 @ScienceBlog3 @MartinJBern @Narvuntien @RidaAller @Tempora23227548 @BL4CKsH33P6 @Climatehope2 @crankyfucker @cjtjgeol @claude_roumain @sapp_erlot @Michael71718318 @CloneDwarf @WinWithScience @Hedendom @Barbarajdurkin @RoyPentland 1/8」The skillfulness of models is dependent on

🗹 1(a). how well the processes which they model are understood, AND

🗹 1(b). how faithfully those processes are simulated in the computer code, AND

🗹 2. whether the results can be repeatedly tested so the models can be refined.

@rdqBlueRidge @TWTThisIsNow @25_cycle @Rose1962bush @SlymasterSteven @ejwwest @Willard1951 @insane_voice @AGWIsHappening @Gordon_DHG @TheDisproof @Stephen90045069 @AristotleMrs @Canadianworker2 @PierreTherrie19 @IceAge2150 @Nockit1 @JohnGiuliano7 @Robert76907841 @1Astroturf @UlaLomu @Moderna5G_666 @MikeDel21893959 @DanielMcDonald4 @mel_wright123 @ScienceBlog3 @MartinJBern @Narvuntien @RidaAller @Tempora23227548 @BL4CKsH33P6 @Climatehope2 @crankyfucker @cjtjgeol @claude_roumain @sapp_erlot @Michael71718318 @CloneDwarf @WinWithScience @Hedendom @Barbarajdurkin @RoyPentland 2/8」If you can check ALL those boxes, you can certainly build a useful computer model.

https://twitter.com/ncdave4life/status/1500879759173165062

threadreaderapp.com/thread/1500873…

@rdqBlueRidge @TWTThisIsNow @25_cycle @Rose1962bush @SlymasterSteven @ejwwest @Willard1951 @insane_voice @AGWIsHappening @Gordon_DHG @TheDisproof @Stephen90045069 @AristotleMrs @Canadianworker2 @PierreTherrie19 @IceAge2150 @Nockit1 @JohnGiuliano7 @Robert76907841 @1Astroturf @UlaLomu @Moderna5G_666 @MikeDel21893959 @DanielMcDonald4 @mel_wright123 @ScienceBlog3 @MartinJBern @Narvuntien @RidaAller @Tempora23227548 @BL4CKsH33P6 @Climatehope2 @crankyfucker @cjtjgeol @claude_roumain @sapp_erlot @Michael71718318 @CloneDwarf @WinWithScience @Hedendom @Barbarajdurkin @RoyPentland 3/8」Current GCMs are obviously untested and untestable, because the predictions they make are for the distant future.

The predictions of early GCMs can be compared against reality, but they failed miserably. I wrote this about the most famous of them:
sealevel.info/hansen1988_ret…

@rdqBlueRidge @TWTThisIsNow @25_cycle @Rose1962bush @SlymasterSteven @ejwwest @Willard1951 @insane_voice @AGWIsHappening @Gordon_DHG @TheDisproof @Stephen90045069 @AristotleMrs @Canadianworker2 @PierreTherrie19 @IceAge2150 @Nockit1 @JohnGiuliano7 @Robert76907841 @1Astroturf @UlaLomu @Moderna5G_666 @MikeDel21893959 @DanielMcDonald4 @mel_wright123 @ScienceBlog3 @MartinJBern @Narvuntien @RidaAller @Tempora23227548 @BL4CKsH33P6 @Climatehope2 @crankyfucker @cjtjgeol @claude_roumain @sapp_erlot @Michael71718318 @CloneDwarf @WinWithScience @Hedendom @Barbarajdurkin @RoyPentland 4/8」Weather models and climate models have one problem in common: we don't understand what we're trying to model. Climate models also have a 2nd problem: their predictions are for so far into the future that they can't be checked. They're 100% untestable.

https://twitter.com/ncdave4life/status/1580763513064419329

@rdqBlueRidge @TWTThisIsNow @25_cycle @Rose1962bush @SlymasterSteven @ejwwest @Willard1951 @insane_voice @AGWIsHappening @Gordon_DHG @TheDisproof @Stephen90045069 @AristotleMrs @Canadianworker2 @PierreTherrie19 @IceAge2150 @Nockit1 @JohnGiuliano7 @Robert76907841 @1Astroturf @UlaLomu @Moderna5G_666 @MikeDel21893959 @DanielMcDonald4 @mel_wright123 @ScienceBlog3 @MartinJBern @Narvuntien @RidaAller @Tempora23227548 @BL4CKsH33P6 @Climatehope2 @crankyfucker @cjtjgeol @claude_roumain @sapp_erlot @Michael71718318 @CloneDwarf @WinWithScience @Hedendom @Barbarajdurkin @RoyPentland 5/8」Everyone ridicules weather forecasts but they've gradually improved. That's only because 10-day forecasts are continually tested against reality.

How good do you think weather models would be if their forecasts were untestable?

That's exactly the situation with GCMs.

@rdqBlueRidge @TWTThisIsNow @25_cycle @Rose1962bush @SlymasterSteven @ejwwest @Willard1951 @insane_voice @AGWIsHappening @Gordon_DHG @TheDisproof @Stephen90045069 @AristotleMrs @Canadianworker2 @PierreTherrie19 @IceAge2150 @Nockit1 @JohnGiuliano7 @Robert76907841 @1Astroturf @UlaLomu @Moderna5G_666 @MikeDel21893959 @DanielMcDonald4 @mel_wright123 @ScienceBlog3 @MartinJBern @Narvuntien @RidaAller @Tempora23227548 @BL4CKsH33P6 @Climatehope2 @crankyfucker @cjtjgeol @claude_roumain @sapp_erlot @Michael71718318 @CloneDwarf @WinWithScience @Hedendom @Barbarajdurkin @RoyPentland 6/8」The problem is that for GCMs the validation process takes, at minimum, several decades.

By then the model is long obsolete (and the source code is probably lost).

https://twitter.com/ncdave4life/status/1592340091124736001

@rdqBlueRidge @TWTThisIsNow @25_cycle @Rose1962bush @SlymasterSteven @ejwwest @Willard1951 @insane_voice @AGWIsHappening @Gordon_DHG @TheDisproof @Stephen90045069 @AristotleMrs @Canadianworker2 @PierreTherrie19 @IceAge2150 @Nockit1 @JohnGiuliano7 @Robert76907841 @1Astroturf @UlaLomu @Moderna5G_666 @MikeDel21893959 @DanielMcDonald4 @mel_wright123 @ScienceBlog3 @MartinJBern @Narvuntien @RidaAller @Tempora23227548 @BL4CKsH33P6 @Climatehope2 @crankyfucker @cjtjgeol @claude_roumain @sapp_erlot @Michael71718318 @CloneDwarf @WinWithScience @Hedendom @Barbarajdurkin @RoyPentland 7/8」Ten-day weather models are tested every ten days, and for multiple locations.

Climate models, making predictions for 30-50 years in the future, can be tested every 30-50 years.

That's less effective, to put it mildly.

https://twitter.com/ncdave4life/status/1498542512297889796

@rdqBlueRidge @TWTThisIsNow @25_cycle @Rose1962bush @SlymasterSteven @ejwwest @Willard1951 @insane_voice @AGWIsHappening @Gordon_DHG @TheDisproof @Stephen90045069 @AristotleMrs @Canadianworker2 @PierreTherrie19 @IceAge2150 @Nockit1 @JohnGiuliano7 @Robert76907841 @1Astroturf @UlaLomu @Moderna5G_666 @MikeDel21893959 @DanielMcDonald4 @mel_wright123 @ScienceBlog3 @MartinJBern @Narvuntien @RidaAller @Tempora23227548 @BL4CKsH33P6 @Climatehope2 @crankyfucker @cjtjgeol @claude_roumain @sapp_erlot @Michael71718318 @CloneDwarf @WinWithScience @Hedendom @Barbarajdurkin @RoyPentland 8/8」Ask anyone in the weather biz how good they think weather models would be if they'd NEVER been tested AT ALL, and NEVER corrected when they made inaccurate forecasts. That's the problem with climate models: they're untestable.
wattsupwiththat.com/2020/06/30/the…

sealevel.info/models_wuwt_30…

@rdqBlueRidge @TWTThisIsNow @25_cycle @Rose1962bush @SlymasterSteven @ejwwest @Willard1951 @insane_voice @AGWIsHappening @Gordon_DHG @TheDisproof @Stephen90045069 @AristotleMrs @Canadianworker2 @PierreTherrie19 @IceAge2150 @Nockit1 @JohnGiuliano7 @Robert76907841 @1Astroturf @UlaLomu @Moderna5G_666 @MikeDel21893959 @DanielMcDonald4 @mel_wright123 @ScienceBlog3 @MartinJBern @Narvuntien @RidaAller @Tempora23227548 @BL4CKsH33P6 @Climatehope2 @crankyfucker @cjtjgeol @claude_roumain @sapp_erlot @Michael71718318 @CloneDwarf @WinWithScience @Hedendom @Barbarajdurkin @RoyPentland @ThreadReaderApp @Rattibha @threaddotblue unroll