"We are witnessing a true reversal of ocean circulation in the Southern Hemisphere—something we’ve never seen before,” explains Antonio Turiel, ICM-CSIC researcher and co-author of the study. “While the world is debating the potential collapse of the AMOC in the North Atlantic, we’re seeing that the SMOC is not just weakening, but has reversed. This could have unprecedented global climate impacts.”
Nope.
I had to look up that last part, as it seemed counter-intuitive, but apparently deep ocean water bottoms out at 4 degrees C.
4° is as dense as water gets. After that it starts expanding as it turns into ice. Which is how ice floats. It’s one of those miracles of nature. If ice sank things would be very different.
Can you expand on that or ELI5?
If the crystalline structure of water did not expand from it’s liquid phase (thus lowering it’s density) when it freezes, then ice would not float. Ice would sink trapping everything below it. It’s theorized that this little fact means life likely couldn’t exist if ice didn’t behave this way.
Right, but I still wouldn’t call water that is 4 degrees C as warm. How is deep water warm?
I’m not going to claim to fully understand the nuances, but the sea ice will melt at about -2C and glacial melt will deposit ~1C water into the system. If the deep water is steady at 3C or 4C, sending it up could accelerate melting of both.
Thank you… I’m an idiot and wasn’t thinking about the Southern Ocean as in ‘The’ Southern Ocean… instead I was thinking about it in terms of the oceans in the south (as in, not necessarily glacial). But yes, now I get it and understand. It probably would have helped if I had opened the link to start with.
That was my physics teacher.
“So materials shrink as they get colder.”
“Ma’am, doesn’t ice expand?”
“We don’t talk about that.”
Ice doesn’t expand. Ice as a solid shrinks when getting colder. H2O expands during phase transformation from liquid to solid.