Golfstroom zou al in 2025 in kunnen storten

Pyt van der Galiën

Gisteren schreven we dat de Golfstroom op afzienbare termijn de geest zou kunnen geven. Het gaat in feite om de Atlantic meridional overturning circulation (AMOC). Golfstroom en AMOC zijn verwant, maar niet identiek. De gevolgen zijn overigens nog steeds catastrofaal. Uitleg hier bij Nature. Hopelijk heb je goed opgelet bij wiskunde. Een minder technische samenvatting kun je vinden bij Duurzaam Nieuws. Lees je liever een Twitterdraadje? Ook daar kunnen we in voorzien. Met dank aan de onvolprezen Threadreader app.

Dr Eleanor Frajka-Williams Profile picture
@EleanorFrajka
15h • 11 tweets • 6 min read Twitter logo Read on Twitter
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Will the #AMOC collapse by 2025? Here’s what we know from direct observations (since 2004).
Image from Srokosz & Bryden (2015)
A 🧵 https://t.co/mzTLMObRRrshorturl.at/ryB34
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The #AMOC is highly variable. More variable than scientists expected when the observations was started. @RAPID_AMOC @NOCnews @MiamiRosenstiel https://t.co/KjBGWcIr2wrapid.ac.uk/data.php
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@RAPID_AMOC @NOCnews @MiamiRosenstiel Atmospheric variability can ‘imprint’ on the #AMOC strength. We expected that cooling would matter, but finding out that wind also matters didn’t fit our classical view of the AMOC as a slowly varying circulation.

Jackson et al. (2022) sums it up https://t.co/LZhpNwKKogshorturl.at/dnFY6
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@RAPID_AMOC @NOCnews @MiamiRosenstiel @kieloben @BenMoat1 @JonIRobson The #AMOC can temporarily reverse. In 2009/10, and again later, the northward heat flux of the AMOC stopped and even reversed. Temporarily! (These reversals were due to changing winds.)

@ger_the_sea et al. 2012 https://t.co/dcgVkQAk6sshorturl.at/adgiM
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@RAPID_AMOC @NOCnews @MiamiRosenstiel @kieloben @BenMoat1 @JonIRobson @ger_the_sea Metrics for the strength of the #AMOC at different latitudes give different numbers.

On the one hand, this is unsurprising. The AMOC is a complex system of currents. But it does complicate the picture when talking about a collapse.
https://t.co/mIoVuFL8CBshorturl.at/tFW49
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@RAPID_AMOC @NOCnews @MiamiRosenstiel @kieloben @BenMoat1 @JonIRobson @ger_the_sea The latest study () is based on a statistical analysis of SST fingerprints not #AMOC measurements (remember, only available since 2004). It cites increases in variability as indicating that the system is moving towards a tipping point. https://t.co/asFLXo7jbrshorturl.at/fqyO8
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@RAPID_AMOC @NOCnews @MiamiRosenstiel @kieloben @BenMoat1 @JonIRobson @ger_the_sea Statistical tools can be helpful, but run the risk of over-simplifying relationships in the climate system (i.e., how the #AMOC responds to freshwater, or the net effect of small-scale eddies on large-scale circulation).

Johnson et al. 2019 () https://t.co/70cBxKIb9jshorturl.at/qMW28
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@RAPID_AMOC @NOCnews @MiamiRosenstiel @kieloben @BenMoat1 @JonIRobson @ger_the_sea More complex models don’t necessarily represent those relationships either. On account of models missing key processes, the @IPCC_CH AR6 report reduced confidence to 50% that the #AMOC won’t collapse by 2100.

IPCC AR6 WG1 Chap9 Executive summary (2021)Image

@RAPID_AMOC @NOCnews @MiamiRosenstiel @kieloben @BenMoat1 @JonIRobson @ger_the_sea @IPCC_CH Scientists gathered in @CENunihh to discuss the state of #AMOC research and observations. From the observational (rather than proxy) record, a majority agreed that we don’t yet know how the AMOC will respond to future anthropogenic change.

#AMOC2023 https://t.co/pImBt28LXfshorturl.at/adewO
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@RAPID_AMOC @NOCnews @MiamiRosenstiel @kieloben @BenMoat1 @JonIRobson @ger_the_sea @IPCC_CH @CENunihh @EpocProject @PatrickHeimbach @ShaneKahn @fmkdejong @JohannesKarst @sunke_tk @np_holliday @David_Smeed Summary report in progress. Sneak peak:
– A need to reconcile missing key processes
– New approaches for basin-scale #AMOC understanding
– Compound impacts of AMOC with carbon and cryosphere
– Articulation of societal impacts

Maybe education too. AMOC is not the Gulf Stream.Image

@RAPID_AMOC @NOCnews @MiamiRosenstiel @kieloben @BenMoat1 @JonIRobson @ger_the_sea @IPCC_CH @CENunihh @EpocProject @PatrickHeimbach @ShaneKahn @fmkdejong @JohannesKarst @sunke_tk @np_holliday @David_Smeed See also @EpocProject where we dive deeper into #AMOC proxies, high resolution coupled modelling for missing key processes, and latitude-spanning (34°S to Arctic) approaches and new sensors for carbon/AMOC transports. @HorizonEurope https://t.co/F4VQmoavFhepoc-eu.org
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Uitgelichte afbeelding: CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=542924
Pyt van der Galiën