The world just had the hottest week on record, according to preliminary data. It follows the hottest June on record, with unprecedented sea surface temperatures and record-low Antarctic sea ice extent. #StateOfClimate 🔗 bit.ly/44BysFX

Looking forward to the start of the #AMOC2023 workshop tomorrow morning! See you in person in Hamburg or online. shorturl.at/eyHZ3

Will the #AMOC collapse by 2025? Here’s what we know from direct observations (since 2004). Image from Srokosz & Bryden (2015) shorturl.at/ryB34 A 🧵

RAPID National Oceanography Centre University of Miami Rosenstiel School Arne Biastoch @BenMoat1 Jon Robson Gerard McCarthy IPCC CEN Uni Hamburg @cenunihh.bsky.social EPOC project Patrick Heimbach Shane Elipot Dr Femke de Jong 🌊 @JohannesKarst Sunke Trace-Kleeberg @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.

Right. A few thoughts on the Ditlevsen^2 paper: 1. These studies are really important to understand the risk and timing of AMOC collapse 2. The relationship between AMOC and sea surface temperatures (SST) is strong but nuanced 3. They know the AMOC isn't the Gulf Stream (1/6)

Vandaag voorin de krant:Volgens Deense onderzoekers komt de machtige oceaanstroming in de Noord-Atlantische Oceaan, die het klimaat over een groot deel van de wereld regelt, mogelijk al binnen enkele decennia abrupt tot stilstand. @NIOZnieuws Dr Femke de Jong 🌊 nrc.nl/nieuws/2023/07…

What’s the difference between the #GulfStream and the #AMOC? Isn’t it just ‘you say potato, I say potahto’? A 🧵 Image from NASA 2009 (shorturl.at/giw78)

In the Atlantic Ocean, there are two main large-scale circulations: the gyres and the overturning. #Gyres go round-and-round. They are a ‘horizontal’ circulation (xy-plane) and are found in multiple oceans.

Ollie Tooth @David_Smeed RAPID The overturning goes up and down. It’s a vertical circulation (seen in the yz-plane), and described in a integrative sense (across x-dir) where the net effect is to ‘tip’ the waters over (= overturning). Only found in the Atlantic. (Ok, the A in #AMOC gives it away.)

Ollie Tooth @David_Smeed RAPID Nick Foukal Where is the #GulfStream in all this? It’s part of both the horizontal and vertical circulations! It contains the western boundary current of the gyre and the northward limb of the #AMOC in the northern subtropics. Image from IPCC FAQ 9.3 shorturl.at/ehLR6

Ollie Tooth @David_Smeed RAPID Nick Foukal Major difference #1: #GulfStream v #AMOC The gyres are nicely described by theory. We can write an equation for them. As long as the wind blows and the earth rotates, a gyre will exist. A #GulfStream is essentially unavoidable. Image from Stommel 1948 (shorturl.at/dfvR0)

Ollie Tooth @David_Smeed RAPID Nick Foukal What about the #AMOC? No simple theory explains its existence! In fact doesn’t *need* to exist at all (cf. the Pacific, or an AMOC ‘shut down’ state). And we can’t write down an equation that describes the flow. Talley et al 2010 (shorturl.at/cOUV0)

Ollie Tooth @David_Smeed RAPID Nick Foukal Major difference #2: Heat transport At 26°N, the #gyre moves little heat. ~0.2 PW (0.2 x 10^15 watts). The #AMOC transports almost all the heat (1.2 PW), even though it only claims a fraction of the #GulfStream. Johns et al. 2011 (shorturl.at/wADKV)

Ollie Tooth @David_Smeed RAPID Nick Foukal Shane Elipot Msadek Rym Jon Robson @BenMoat1 Where does that leave us? (1) - #GulfStream spans Florida to Boston. - #AMOC spans South Africa to Arctic. Southern AMOC review (no Gulf Stream needed) from Chidichimo et al. (2023) shorturl.at/kyFNQ María Paz Chidichimo

Ollie Tooth @David_Smeed RAPID Nick Foukal Shane Elipot Msadek Rym Jon Robson @BenMoat1 María Paz Chidichimo Sabrina Speich @CristinaArumi97 Where does that leave us? (2) - #GulfStream transport is large, and contributes to gyres and overturning. - #AMOC is smaller, but dominates heat transport. Review from Jackson et al. (2022) on AMOC since 1980 shorturl.at/dnFY6

‘Era of global boiling has arrived,’ says UN chief as July set to be hottest month on record theguardian.com/science/2023/j…

Deliberate tracer release experiments (TREs) are needed for MRV of ocean CO₂ removal (CDR). We need to develop the expertise. If you are a Ph.D. student or recent Ph.D. and interested in joining a cruise to the Labrador Sea in Nov/Dec 2023 to assist with a TRE, please email me.